Source: TEXAS A&M UNIVERSITY submitted to
VEGETABLE CROPPING SYSTEM MANAGEMENT IN RELATION TO ENVIRONMENTAL STRESSES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
REVISED
Funding Source
Reporting Frequency
Annual
Accession No.
0156441
Grant No.
(N/A)
Project No.
TEX08098
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Dec 4, 2009
Project End Date
Dec 3, 2014
Grant Year
(N/A)
Project Director
Leskovar, D. I.
Recipient Organization
TEXAS A&M UNIVERSITY
750 AGRONOMY RD STE 2701
COLLEGE STATION,TX 77843-0001
Performing Department
Uvalde-TAMU Agr Res & Ext Cntr
Non Technical Summary
In the last decade, vegetable crop production in Texas has been subjected to increasing environmental constraints, particularly drought and water limitations, causing extreme impact in the rural economies. Climatic models indicate that drought will become increasingly common in the future. For example, 2009 was the worst drought in 50 years, with record-high temperatures and record-low rainfall in south/central regions of Texas causing $3.6 billion losses in crop and livestock production. Therefore, understanding plant and crop responses to drought, high temperature, wind, and nutrient balance is critical to develop sustainable cropping systems and tolerant genotypes to maintain or improve crop productivity and increase product quality. In Texas in 2008, major vegetable crops for fresh market and processing were grown under conventional systems across 74,400 acres (not including potatoes), with a total value of $276 million for fresh market and processed types and an economic impact of about $1 billion. In terms of value, the major crops for Texas are watermelon, onion, cabbage, and chile/jalapeno pepper and spinach. In the Wintergarden region, predominant spring crops are watermelon, cantaloupe, cucumber, pepper, green bean, and potato, while fall-winter crops are onion, cabbage, spinach, carrot, broccoli, cauliflower and more recently romaine lettuce. Other small scale specialty crops grown commercially, or on experimental basis, are tomato, eggplant, habanero pepper, cilantro, turnip, collards, kale, mustard, herbs and more recently artichoke. This project will address environmental constraints during seedling establishment, crop development and maturity. It will also focus on adaptation of new cultivars known to possess high yield potential and high levels of phytochemicals. Emphasis will be on the morphological and physiological characterization of root/shoot responses in order to better understand plant acclimation. This understanding is a pre-requisite to develop improved production strategies under those limited environments.
Animal Health Component
45%
Research Effort Categories
Basic
45%
Applied
45%
Developmental
10%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1111499102030%
2021499102015%
2031499102030%
2041499102025%
Goals / Objectives
1. Elucidate plant stress tolerance mechanisms and develop seedling conditioning treatments to improve transplant quality and stand establishment. 2. Determine physiological responses, root/shoot growth, water use efficiency, yield and product quality in response to water conservation practices and improved cropping systems. 3. Identify genetic, pre-harvest factors and environmental variability for traits related to phytochemicals, product quality and yield. 4. Evaluate, develop and implement sustainable crop strategies for selected high-income crops with adaptation to southwest Texas environments. We expect that higher yields and production efficiency resulting from the application of integrated strategies and in combination with adapted cultivars will enhance profitability over the long term. The economic benefits for producers and shippers will be measured by increased product market value and marketable yields. Social benefits include increased availability of locally-produced healthy vegetable products for consumers. Environmental benefits include progression towards sustainable vegetable production systems, with reduced negative impacts on soil quality, water and beneficial organisms. Furthermore, by implementing crop strategies for key high value crops (e.g. artichokes, specialty peppers) we expect to help revitalize local economies and also reduce the high production and transportation costs (carbon footprints) of these vegetables from the West and Eastern states to Central U.S. markets.
Project Methods
Field, greenhouse and laboratory experiments will be conducted primarily at the Texas AgriLife Research Center at Uvalde with complementary studies in Weslaco, Amarillo and College Station (Vegetable and Fruit Improvement Center, Borlaug Center). Implementation of improved cropping systems will be conducted in growers' fields located in diverse eco-regions of Texas including the Wintergarden, Rio Grande Valley and the High Plains. Objective 1. Abscisic acid and ethylene (both promoters and inhibitors) will be evaluated on growth and physiology of vegetable seedlings (such as pepper, tomato and watermelon) exposed to short and long cycles of desiccation, in order to improve transplant stress tolerance. To develop seedling conditioning treatments aimed at improving transplant quality, ABA will be evaluated on growth modulation during early stages of seedling development. Additionally, methods of foliar ABA application based on timing and frequency will be screened to control mature vegetable transplants in a greenhouse for improved growth and survival. Objective 2. Soil moisture levels will be monitored with Echo probes at various depths depending on the crop. Root growth and development will be monitored at critical stages using a Minirhizotron system. Soil moisture data in conjunction with evapotranspiration data (ET) will be used to establish irrigation rates. Irrigation scheduling will be triggered by those parameters in conjunction with canopy temperature measured by infrared thermometers. We will collect data on soil quality, root growth, canopy development, yield and product quality under control and deficit irrigation regimes. Physiological measurements include leaf photosynthesis, stomatal conductance, water potential, relative water content, electrolyte leakage, and canopy temperature. Objective 3. Onion, spinach, artichoke, carrots, melon and pepper genotypes will be evaluated under several pre-harvest strategies with emphasis on limited irrigation, low N inputs, plant growth regulators and variable plant populations aimed at machine harvesting. Soil moisture, growth, yield and sensory quality parameters will be measured by standard methods. Flavonoids, carotenoids, and vitamin C will be measured by HPLC. Soil and plant nitrate-N and ammonium-N will be measured by a colorimetric discrete analyzer. Objective 4. Screening, development and commercial implementation of new pepper, onion, melon and artichoke TAMU germplasm will continue. We will focus on traits that show promise such as high temperature tolerance, high fruit set, balanced shoot/root growth, desired plant architecture for machine harvesting, and adaptability for water-restricted regions. In artichoke, an emerging crop in Texas, we will characterize genotypes variability to water deficit utilizing morphological descriptors, physiological responses and molecular markers.

Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: Abscisic acid (ABA) treatments based on spray volume and concentrations were evaluated to optimize the application rate in jalapeno pepper (Capsicum annuum L., cv. Colima) and triploid watermelon (Citrullus lanatus,cv. Majestic) under greenhouse conditions. Similarly, timing and rate of applications of two new cytokinin formulations were evaluated for its effect on growth and yield of bell pepper under field conditions. Artichoke and specialty melons are novel crops with high economic potential for small and commercial producers in southern U.S. In artichoke we evaluated crop strategies that included planting configurations, plasticulture, and cultivars differing in maturity. In melons, deficit irrigation is an important strategy for sustaining productivity in water limiting regions affected by prolonged droughts. Three melon cultivars, Mission (Cantaloupe; reticulatus), Da Vinci (Tuscan; reticulatus) and Super Nectar (Honeydew; inodorus) were evaluated at two irrigation regimes with a sub surface drip system under black plastic mulch at 100% and 50% crop evapotranspiration (ETc) rates. Melon genotype by environment (GxE) trials were also conducted to determine the stability of fruit yield and component traits for nine genotypes including four commercial hybrids which were planted at three Texas locations: College Station, Uvalde and Weslaco. Several invited and volunteer poster and oral papers were presented in regional, state, national and international horticultural conferences. Presentations focused on the following areas: transplant stress and drought tolerance, stand establishment systems, crop strategies for melons and artichoke, phytonutrients in vegetable crops, deficit irrigation, and genotype-environment interactions for pepper and melon. Results were also disseminated through radio and newspaper media at local, regional, state and national channels. PARTICIPANTS: Individuals: Kevin Crosby, Marco Palma, Kilsun Yoo, John Jifon, Bhimu Patil, Haejeen Bang, David Forbes, Susan Cooper, Raul Cabrera, Mario Pagnotta, Juan A. Franco, Dirk Hays. Partner Organization and Collaborators: Texas Water Resources Institute, Irrigation Technology Center, Southwest Texas Junior College, Vegetable and Fruit Improvement Center, Valent BioSciences, Texas Department of Agriculture, Winter Garden Produce, Speedling Inc., Michael Ortiz at Brownsville, Becker Vineyards at Stonewall. TARGET AUDIENCES: Vegetable grower popular press, small and large commercial growers, seed industry, irrigation suppliers, transplant nurseries and consumers. Commodity groups, water Agencies, Texas Department of Agriculture. Extension and research faculty participating in the Rio Grande Basin Initiative and Food for Health programs. Members of the Seed and Stand Establishment working groups (ASHS and ISHS), Members of the Artichoke working group (ISHS), Members of the Vegetable Section at ISHS, and the American Society of Plant Growth Regulators. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The transplant size response to ABA application in pepper was proportional to the application rate. ABA is an effective treatment to control transplant size, but it should not exceed 0.47 mg per plant for jalapeno pepper or 0.18 mg for triploid watermelon to avoid detrimental effects on plant appearance and post-planting growth. Field applications of two cytokinin formulations were ineffective in promoting growth, yield and quality of bell pepper under field conditions. Irrigation water is becoming increasingly limited in southwest Texas. The results of artichoke studies indicate that one line per bed with plastic mulch and subsurface drip is recommended as an annual system of production based on increased yield, head size and about 20% water savings as compared to baresoil system. In specialty melons, root length density increased significantly at 50% ETc (by 120%) in cv. Mission, decreased (19%) in Da Vinci and remained unchanged in Super Nectar. Deficit irrigation saved 36% in water application in cvs. Mission and Da Vinci, without significant reduction in marketable yield. These cultivars also exhibited some drought tolerance and improved photosynthetic rate, thus they are better choices for water-limited regions than the inodorus type. Genotypic evaluation in multi-environments is essential to better understand the nature and magnitude of genotype by environment interactions for any desirable trait. From the nine melon genotypes evaluated in three locations, Mission was the most stable and average performing genotype for marketable yield across all environments, while the Uvalde location was the most ideal environment for selecting cultivars adapted to south-central Texas. Irrigation studies conducted in spinach over three seasons, suggest that 75% ETc could be considered as an efficient irrigation strategy during drought seasons without causing significant yield reduction.

Publications

  • Sharma, S.P., Leskovar, D.I., Crosby, K.M. and Volder, A. (2012). Deficit irrigation effects on gas exchange, root growth, and fruit yield of melons. Abstracts of Annual Conference of the ASHS, July 31-Aug. 3, 2012. HortScience: 47 (9) (Supplement): S309.
  • Sharma, S.P., Leskovar, D.I., Crosby, K.M. and Ibrahim, A. (2012). Biplot analysis of GxE interactions for fruit yield and component traits in melons (Cucumis melo L.). Abstracts of Annual Conference of the ASHS, July 31-Aug. 3, 2012. HortScience: 47 (9) (Supplement): S185.
  • Sharma, S.P., Leskovar, D.I., Crosby, K.M. and Volder, A. (2012). Water uptake, yield and fruit quality of specialty melons (Cumcumis melo L.) under deficit irrigation.In: Abstracts of Annual Meeting of the SR-ASHS, February 4-6, 2012. HortScience: 47 (9) (Supplement): S8
  • Crosby, K., Leskovar, D. and Jifon, J. (2012). Screening peppers for resistance to leafminer (Liriomyza spp.). 2012 National Pepper Conference, Naples, FL.
  • Crosby, K., Gonzalez, J., Leskovar, D.I. and Isakeit, T. (2012). Characterization and deployment of recessive resistance to Phytophthora capsici in Capsicum annuum. Abstracts of Annual Conference of the ASHS, July 31-Aug. 3, 2012. HortScience: 47 (9) (Supplement): S186
  • Leskovar, D.I., Xu, C. and Agehara, S. (2012). Planting configuration and mulch affect growth and yield of globe artichoke. Abstracts of Annual Conference of the ASHS, July 31-Aug. 3, 2012. HortScience: 47 (9) (Supplement): S172.
  • Agehara, S. and Leskovar, D.I. (2012). Impact of ABA applications on growth and yield of watermelon transplants. Abstracts of Annual Conference of the SR-ASHS, Feb. 3-6, 2012. HortScience: 47 (9) (Supplement): S51.
  • Agehara, S. and Leskovar, D.I. (2012a). Abscisic acid-induced chlorosis is leaf age dependent and can occur independently of ethylene in Arabidopsis. Hortscience 47(9):S311 (abstr.).
  • Agehara, S. and Leskovar, D.I. (2012b). Optimizing abscisic acid foliar application for size control of pepper and watermelon transplants. Hortscience 47(9):S35 (abstr.).
  • Agehara, S. and Leskovar, D.I. (2012). Abscisic acid controls growth of jalapeno pepper transplants. 6th International Symposium on Seed, Transplant and Stand Establishment of Horticultural Crops (Brazillia-DF, Brazil) Abst.#88.
  • Leskovar, D.I., Xu, C., Agehara, S., Sharma, S.P. and Hensarling, C. (2012). Deficit irrigation and planting system for spinach in southwest Texas. 2012. International Spinach Conference, San Antonio, Texas.
  • Lee, E., Yoo, K., Leskovar, D. and Patil, B. (2012). Development of an automated method for Folin-Ciocalteu total phenolic assay in artichoke extracts. Journal of Food Science, 0846.R1.
  • Agehara, S. and Leskovar, D.I. (2012). Characterizing concentration effects of exogenous abscisic acid on gas exchange, water relations, and growth of muskmelon seedlings during water stress and rehydration. Journal of the American Society for Horticultural Science 137(6):400-410.
  • Butcher, J.D., Crosby, K.M., Yoo, K.S., Patil, B.S., Ibrahim, A.M.H., Leskovar, D.I., and Jifon, J.L. (2012). Environmental and genotypic variation of capsaicinoid and flavonoid concentrations in Habanero (Capsicum chinense) peppers. HortScience 47(5): 574-579.
  • Leskovar, D., Agehara, S., Yoo, K. and Pascual-Seva, N. (2012). Crop coefficient-based deficit irrigation and planting density for onion: growth, yield and bulb quality. HortScience 47(1):31-37.
  • Kahn, B. and Leskovar, D. (2012). Cropping systems. In: Russo, V. (ed) Peppers: Botany, production and uses. CABI. pp. 137-149.
  • Leskovar, D. and Kahn, B. (2012). Stand establishment. In: Russo, V. (ed) Peppers: Botany, production and uses. CABI. pp. 112-124.
  • Jifon, J., Lester, G., Stewart, M., Crosby, K., Leskovar, D.I. and Patil, B.S. (2012). Fertilizer use and functional quality of fruits and vegetables. In Fertilizing Crops to Improve Human Health: A Scientific Review, IFA-IPNI, 191-214.
  • Sharma, S.P., Leskovar, D.I., Crosby, K.M. and Volder, A. (2012). Water uptake, yield and fruit quality of specialty melons (Cumcumis melo L.) under deficit irrigation. In: Abstracts of Annual Meeting of the SR-ASHS, February 4-6, 2012. HortScience: 47 (9) (Supplement): S8.


Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: We are investigating three plant growth regulators to improve transplant quality, growth, fruit quality and yield of vegetable species. Applications of abscisic acid (ABA) were evaluated on jalapeno pepper and triploid watermelon transplants for their effect on size control, field survival and yield. ABA was also applied as a means to control growth of mature watermelon transplants (5 to 8 weeks old). As a follow up experiment from last year 1-MCP applied 7 and 14 days after flowering was evaluated for its potential to increase fruit set and marketable yield in cantaloupe and honeydew melons grown under drip irrigation and plastic mulch system. Similarly, 6-BA, a cytokinin-type growth regulator was evaluated for its effectiveness as foliar applications on yield and fruit quality of bell pepper and four specialty melons. A new study was established to identify melon genotypes possessing vigorous root system, high productivity and with higher level of B-carotene, ascorbic acid and sugars under varying environments. Nine yellow fleshed melon (Cucumis melo L.) genotypes from the Cantalupensis and Inodorus group were evaluated for quality and yield traits at three locations in Texas. In addition, a cantaloupe and two specialty melon cultivars were evaluated under deficit irrigation for root growth, yield and quality traits. We continue research on globe artichoke production strategies based on planting configuration (single or double lines), mulching (plasticulture or bare soil) and cultivar (early: Imperial Star or late: Green Globe). We also continue screening advanced hot pepper and melon genotypes for yield, concentrated fruit set, pest resistance and improved quality traits. Several invited and volunteer oral and poster papers were presented in regional, national and international horticultural conferences. They described research on plant growth regulator applications for vegetable crops, stand establishment, artichoke crop strategies, deficit irrigation effects on yield, quality and phytonutirents, and genotype x environment interactions for melon traits. Results were also disseminated through news media (radio interviews, websites and popular press). PARTICIPANTS: Individuals: Kevin Crosby, Kilsun Yoo, John Jifon, Bhimu Patil, Haejeen Bang, David Forbes, Susan Cooper, Tom Cothren, Juan Fernandez, Juan A. Franco. Partner Organization and Collaborators: Texas Water Resources Institute, Vegetable and Fruit Improvement Center, Valent BioSciences, AgroFresh, Texas Department of Agriculture, Winter Garden Produce, Speedling Inc. at Alamo, TX; Michael Ortiz at Brownsville, Becker Vineyards at Stonewall. TARGET AUDIENCES: Vegetable grower popular press, small and large commercial growers, seed industry, irrigation suppliers, transplant nurseries and consumers. Texas Department of Agriculture. Extension and research colleagues participating in the Rio Grande Basin Initiative and Food for Health programs. Members of the Seed and Stand Establishment working groups (ASHS and ISHS), Members of the Artichoke working group (ISHS), Members of the Vegetable Section at ISHS, and the American Society of Plant Growth Regulators. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Although ABA did not affect plant height, it reduced shoot dry weight by 16 to 23%. In both jalapeno pepper and triploid watermelon, these differences diminished gradually after transplanting and no yield differences were observed. These results suggest that ABA foliar application is effective to control size of vegetable transplants and its growth inhibiting effects are only transient. The effectiveness of ABA is strongly dependent on species and transplant age. In another experiment on triploid watermelon, foliar application of ABA was more effective on improving growth and yield when applied to 5-week old transplants as compared to untreated plants. Overall, applications of 1-MCP during flowering were not effective in increasing fruit set and yield of muskmelon when tested in two field plantings during spring. Similarly 1-MCP did not affect fruit set and yield when tested in five different specialty melon cultivars. 6-BA was effective to improve early yield in bell pepper mainly by increasing fruit number per plant. Conversely, 6-BA did not improve yield or fruit size on any of the four specialty melons tested. In cantaloupe and Tuscan-type melons, the use of 50% ETc irrigation applied through drip under after plants were fully established saved considerable amount of irrigation water (36%) without significant loss in fruit yield and quality. However, the honeydew melon (Inodorus group) was more sensitive to deficit irrigation, even though water uptake was higher at deeper soil layers. In artichokes, the single line system under mulch increased yield and earliness as compared to double-lines and bare soil system for both cultivars. We are currently partnering with a grower in south Texas who is producing 30 acres of artichokes. Producing fresh, locally grown, and high quality artichoke heads may provide an opportunity to expand rural economies. From the pepper breeding and vegetable physiology collaborative program we jointly released 15 disclosures for jalapeno inbred lines and 3 habanero lines.

Publications

  • Shinohara, T., Agehara, S., Yoo, K. and D.I. Leskovar. 2011. Irrigation and nitrogen management of artichoke: yield, head quality, and phenolic content . HortScience 46(3):377-386.
  • Wang, T., Sistrunk, L.A., Leskovar, D.I. and B.G. Cobb. 2011. Characteristics of storage reserves of triploid watermelon seeds: association of starch and mean germination rate. Seed Science and Technology 39, 318-326.
  • Jifon, J., Lester, G., Stewart, M., Crosby, K. and D. I. Leskovar. 2011. Fertilizer use and functional quality of fruits and vegetables (in press, IFA-IPNI Fertilizer Use and Human Health).
  • Leskovar, D.I., Agehara, S., Jifon, J., Crosby, K., Rush, C. and S. Goreta-Ban. 2011. Foliar ABA sprays controlled growth and improved survival and desiccation tolerance of vegetable transplants. Acta Horticulturae, 898, 237-244.
  • Crosby, K., Butcher, J., Yoo, K. and D.I. Leskovar. 2011. Caro Tex 312 An F1 hybrid, high yielding, multiple disease resistant orange habanero pepper cultivar. ASHS Annual Conference. p.49 (Abstr.)
  • Leskovar, D.I. and S. Agehara. 2011. Impact of 1-MCP spray during flowering on fruit set and yield of cantaloupe. ASHS Annual Conference. p. 86 (Abstr.)
  • Agehara, S. and D.I. Leskovar. 2011. Abscisic acid controls size of pepper and watermelon transplants. ASHS Annual Conference. p.105 (Abstr.)
  • Crosby, K., Jifon, J., and D. Leskovar. 2011. Evaluation of new experimental tomato hybrids from the Texas A&M Vegetable Improvement Center. HortSci 46(9): S25.
  • Butcher, J.D., Crosby, K.M., Leskovar, D.I., Jifon, J., Yoo, K.S., and B. Patil. 2011. Quantifying ascorbic acid, flavonoid, and capsaicin levels in different peppers (Capsicum annuum) grown in two different Texas locations. HortSci 46(9): S23.
  • Leskovar, D.I., Shinohara, T., Agehara, S., Cooper, S., Yoo, K.S. and B. Patil. 2011. Crop strategies for globe artichoke in Texas. 71th Annual Meeting of the Southern Region of the American Society for Horticultural Sciences, Corpus Christi.
  • Leskovar, D.I., Agehara, S., Jifon, J. and K. Crosby. 2011. Applications of ABA for vegetable transplants: physiological conditioning, development and survival. 38th Annual Meeting of the Plant Growth Regulation Society of America, Chicago.
  • Agehara, S. and D.I. Leskovar. 2011. Exogenous abscisic acid as a size control agent for pepper and watermelon transplants. 38th Annual Meeting of the Plant Growth Regulation Society of America, Chicago.
  • Leskovar, D.I. and S. Agehara. 2011. 1-MCP spray for cantaloupe: fruit set and yield. 38th Annual Meeting of the Plant Growth Regulation Society of America, Chicago.
  • Jifon, J.L., Leskovar, D.I., Crosby, K.M., and J. Enciso. 2011. Stand establishment and water productivity of grafted watermelons: effects of planting density and deficit irrigation. HortSci. 46(9): S61.
  • Leskovar, D., and S. Agehara. 2011. Improving transplant quality and stand establishment of vegetable transplants under abiotic stresses. Multistate W2168 Meeting, July 7, Ames, Iowa State University.
  • Agehara, S. and D. Leskovar. 2011. Effectiveness of exogenous abscisic acid to alleviate water stress in muskmelon transplants is concentration dependent. Department of Horticultural Sciences 2nd place poster competition. Texas A&M University.


Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: Hormonal (abscisic acid, ABA) treatments were evaluated as a means to mitigate drought stress in jalapeno and bell pepper types under greenhouse and field conditions. 1-MCP (an inhibitor of ethylene) was studied as a potential tool to increase fruit set in cucurbit crops under field conditions. We are investigating deficit irrigation strategies for cool season crops (spinach and onion) and planting systems strategies (mulching and plant configurations) for yield, quality and water use efficiency of globe artichokes. Spinach is well known for its high lutein and β-carotene content and onions for its thiosulfides and flavonoid compounds. Artichoke is a novel crop with high economic potential for small producers. Advance pepper and melon genotypes were screened for yield, pest resistance and quality traits and are being considered for seed increase for large field testing in commercial fields. The goal is to develop sustainable production strategies that can be implemented into commercial settings in Texas. In addition, we expect to diversify vegetable production with new products that have the potential to increase income for producers and industry, while providing consumers attractive products with high flavor, taste, and antioxidant potential. Five project updates and several invited and volunteer oral papers were presented in national and international horticultural conferences. They described our work on transplant shock and drought tolerance, stand establishment, crop strategies for artichoke, phytonutrients, deficit irrigation, and genotype-environment interactions for pepper and melon. Results were also disseminated through news media (radio interviews and websites), through local, state, regional and nationwide channels. The project on transplant shock and deficit irrigation for onions appeared in 63 online News outlets. PARTICIPANTS: Individuals: Kevin Crosby, Kilsun Yoo, John Jifon, Bhimu Patil, Genhua Niu, Diane Rowland, Brian Kahn, Haejeen Bang, David Forbes, Susan Cooper, Tom Cothren, Juan Fernandez, and Mario Pagnotta. Partner Organization and Collaborators: Texas Water Resources Institute, Vegetable and Fruit Improvement Center, Valent BioSciences, AgroFresh, NIFA, Winter Garden Produce, Jimmy Crawford, Brandon Laffere, Speedling Inc. at Alamo, TX and Sun City, FL. TARGET AUDIENCES: Small and large commercial vegetable growers, seed industry, transplant nurseries and consumers. Commodity groups, spinach producer board, water groups, Texas Department of Agriculture. Extension and research colleagues participating in the Rio Grande Basin Initiative and Food for Health programs. Members of the Seed and Stand Establishment working gropus (ASHS and ISHS), and the American Society of Plant Growth Regulators. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Spraying ABA one week before transplanting improved drought tolerance characteristics (compact size with high root to shoot ratio) in jalapeno transplants. Field applications of ABA on bell pepper resulted in slow growth, delayed fruit set, and yield reductions under both optimum and deficit irrigation. Treatment with ABA before water stress was effective in maintaining water relations and promoting post-stress recovery of melon transplants. In artichokes, the single line planting system produced more number of heads per plant and at least 60% higher marketable yield than the double line system. Overall plasticulture enhanced earliness of artichoke bud formation by 1-2 weeks, and increased yield by 4-32% depending on cultivar. The results from the onion study suggest that growers could adjust planting densities and implement water conserving practices to target high-price bulb sizes without reducing flavor or nutritional components. We estimate 2,500 acre-feet of water could be saved by utilizing 75% ETc irrigation rate. Small commercial fields were established with growers in Brownsville and Carrizo Springs. In melons, we initiated a study to determine the stability and mean performance of various melon genotypes for fruit yield, β-carotene, vitamin C and sugar content over three different environments (Uvalde, Weslaco and College Station). From the pepper breeding and production physiology program we jointly released 12 disclosures. Those included 1 cayenne, 7 jalapenos, and 4 serrano pepper types.

Publications

  • Leskovar, D. and M. Bari. 2010. Il carciofo in USA. In: Il carciofo. Angelini e Calabrese eds. BayerCropScience, Milano, Italia. pp. 406-411.
  • Jifon, J.L., G. Lester, M. Stewart, K. Crosby, and D.I. Leskovar. 2010. Fertilizer use and functional quality of fruits and vegetables. Chapter 9: In T. Bruulsema, P. Heffer, Moran, R. Welch, I. Cakmak (eds) Fertilizer Use and Human Health. In Press: The International Fertilizer Industry Association (IFA) and the International Plant Nutrition Institute (IPNI).
  • Niu, G., Rodriguez, D., Cabrera, R., Jifon, J., Leskovar, D. and K. Crosby. 2010. Salinity and soil type effects on emergence and growth of pepper seedlings. HortScience 45:1265-1269.
  • Niu, G., Rodriguez, D., Crosby, K., Leskovar, D. and J. Jifon. 2010. Rapid screening for relative salt tolerance among chile pepper genotypes. HortScience 45: 1192-1195.
  • Bang, H., Davis, A. Kim, S. Leskovar, D. and S.R. King. 2010. Flesh color inheritance and gene interactions among canary yellow, pale yellow and red watermelon. J. Amer. Soc. Hort. Science. 135(4)362-368.
  • Crosby, K.M., Butcher, J., Yoo, K.S., and D.I. Leskovar. 2010. TAM Ben Villalon- a new multiple-virus resistant, mild, green-chile pepper. HortSci. 45(11): 1756-1758.
  • Crosby, K., Leskovar, D., and M. Miller. 2010. Evidence that resistance to gummy stem blight (Didymella bryoniae) in Dudaim type melons (Cucumis melo ssp. agrestis) is a quantitative trait. In: Eds-J. Thies, S. Kousik, A. Levi, Cucurbitaceae 2010 Proceedings, ASHS Press, Alexandria, VA, USA.
  • Agehara, S. and D.I. Leskovar. 2010. Optimizing foliar application of abscisic acid to improve drought tolerance of melon. HortScience 45(8):S50. (Abstr.)
  • Jifon, J., Leskovar, D. and K. Crosby. 2010. Rootstock effects on the water relations of grafted watermelons. HortScience 45(8):S213. (Abstr.)
  • Shinohara, T., Agehara, S. and D.I. Leskovar. 2010. Growth and physiology of artichoke transplants exposed to aba, heat, and drought stresses. HortScience 45(8):S51. (Abstr.)
  • Crosby, K.M, Jifon, J.L and D.I. Leskovar. 2010. Developing cantaloupe lines with resistance to multiple vine decline pathogens. HortSci. 45(4): 502.
  • Jifon J.L., G. Niu, K. Crosby, and D. Leskovar. 2010. Hydraulic conductance characteristics of rootstocks for watermelon grafting. HortSci. 45(4):516-17.
  • Leskovar, D. 2010. Stress tolerance of vegetable transplants. RGBI annual conference. Alpine, Texas. May 17-20, 2010.
  • Leskovar, D. , Agehara, S. & Yoo, K.(2010). Deficit irrigation and plant density impact on growth, yield, bulb quality and quercetin of short-day onion. IHC-ISHS (Abstr.)
  • Wen, Y., D.L. Rowland, G. Piccinni, J.T. Cothren, D.I. Leskovar, A.R. Kemanian and T.K. Witten. 2010. Cotton production under traditional and regulated deficit irrigation schemes in Southwest Texas (final report). Proc. of the 2010 ASA-CSSA-SSSA International Annual Meetings, Long Beach, CA. (Oral)
  • Wen, Y., G. Piccinni, J.T. Cothren, D.I. Leskovar, D.L. Rowland and A.R. Kemanian. 2010. Regulated deficit irrigation application and the physiological responses of cotton (Gossypium hirsutum L.) in Southwest Texas (updated report). Proc. of the 2010 Beltwide Cotton Conferences, New Orleans, LA. (Oral)
  • Wen, Y., G. Piccinni, J.T. Cothren, D.I. Leskovar, D.L. Rowland and A.R. Kemanian. 2010. The lint yield and fiber quality of cotton (Gossypium hirsutum L.) under several regulated deficit irrigation schemes in Southwest Texas. Proc. of the 2010 Beltwide Cotton Conferences, New Orleans, LA. (Poster)
  • Wen, Y., G. Piccinni, J.T. Cothren, D.I. Leskovar, D.L. Rowland and A.R. Kemanian. 2009. Regulated deficit irrigation and cotton production responses in Southwest Texas. Proc. of the 5th USCID Irrigation and Drainage International Conference, Salt Lake City, UT. [P289-300]
  • Wen, Y., G. Piccinni, J.T. Cothren, D.I. Leskovar, D.L. Rowland and A.R. Kemanian. 2009. Regulated deficit irrigation application and the physiological responses of cotton (Gossypium hirsutum L.) in Southwest Texas (updated report). Proc. of the 2009 ASA-CSSA-SSSA International Annual Meetings, Pittsburgh, PA. (Poster) [#701 OR Session No: 65-6.]
  • Wen, Y., G. Piccinni, J.T. Cothren, D.I. Leskovar and A.R. Kemanian. 2009. Regulated deficit irrigation application and the physiological responses of cotton (Gossypium hirsutum L.) in Southwest Texas. Proc. of the 2009 Beltwide Cotton Conferences, San Antonio, TX. (Oral) [@63rd Cotton Agronomy & Physiology Conference - Session B]


Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: The potential hormonal regulation to acclimate transplants for mitigating chilling and drought stress was investigated under field conditions in the Wintergarden and High Plains of Texas. We are developing an integrated system for artichoke production in southwest Texas. Investigations are on applications of gibberellic acid to induced bolting and be able to produce in late fall. We have established an experiment to determine the interactive effect of planting configuration and mulching on yield and quality of two cultivars differing in maturity, and we continue screening green and red head artichoke cultivars for adaptability to the region. Furthermore, since depredation of artichoke transplants by wild white-tailed deer can reduce field stands significantly we conducted feeding trials with captive white-tailed deer. Studies on water management (deficit irrigation) on yield, quality and phytochemicals of winter crops were established. Onion and spinach crops were evaluated at three deficit irrigation regimes and two plant populations using single or wide beds, while another deficit irrigation experiment was initiated on broccoli and cabbage. Advance onion breeding materials, primarily white and yellow yypes were evaluated for growth, yield and quality. Best materials were selected for planting in the 2010 season. We screened experimental and commercial hybrids of traditional and specialty peppers, included new Texas AgriLife pepper with adaptation to semi-arid conditions and improved traits related to yield and quality. Four invited (1 international, 2 national, 1 state) and 19 volunteer presentations depicted our work in stress tolerance of vegetable transplants, stand establishment, integrated production system of artichoke, deficit irrigation effects on yield, quality and phytochemicals, and genotype-environment interactions for pepper and melon. Results from this program were also presented in several websites and news media releases. PARTICIPANTS: Individuals: Kevin Crosby, Kilsun Yoo, John Jifon, Bhimu Patil, Charlie Rush, Diane Rowland, Brian Kahn, Juan Fernandez. Partner Organization: Texas Water Resources Institute, Texas Water Development Board, Vegetable and Fruit Improvement Center, Georgia Pacific, Valent BioSciences, AgroFresh, USDA. Collaborators: Constanzo Farm, Brandon Laffere, South Cross Vegetable Transplants, Cargil Produce, Speedling Inc. (Alamo, TX and Sun City, FL), Tropical Star. Training graduate students: Shinsuke Agehara, Sat Pal Sharma, Libbie Johnson. Undergraduate student training: 4 TARGET AUDIENCES: Vegetable growers, consumers, seed industry and transplant nurseries. Commodity groups, spinach producer board, water groups, Texas Department of Agriculture. Extension and research colleagues participating in the Rio Grande Basin Initiative and Food for Health programs. Members of the Seed and Stand Establishment working gropus (ASHS and ISHS), and the American Society of Plant Growth Regulators. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Watermelon survival rates increased when transplants were treated with ABA in the nursery. Marketable yields significantly increased with ABA applications in the nursery and field as compared to control. Similarly, marketable yields significantly increased for jalapeno peppers when ABA was applied in the nursery. This response was associated with better plant recovery under chilling and drought stress. From our experiment in artichoke we concluded that GA3 applied at 30 ppm two to three times at 14-day intervals allowed a harvest extension of at least 2 additional months. In terms of yield, the top cultivars were Emerald, Imperial Star, Madrigal, Green Globe Improved and Experimental Red. Cultivars with the largest head size were Opal, Concerto, Green Globe Improved and Experimental Red. From our artichoke feeding trials, we determined that deer consistently preferred to eat the most mature (as opposed to young) transplant foliage offered. In short day onion, total yields were higher for the highest plant density, though bulb size decreased significantly, while deficit irrigation (75% ETc) slightly decreased onion marketable yields, but not bulb quality or flavonoid contents. From our collaborative plant breeding-production physiology pepper program, several jalapenos, serranos and one cayenne were submitted for licensing to TAMU-OTC.

Publications

  • Websites and news releases. 2009. http://southwestfarmpress.com/news_archive/artichokes-texas-1216/
  • Piccinni, G., Ko, J., Marek, T. and D.I. Leskovar. 2009. Crop coefficients specific to multiple phenological stages for evapotranspiration-based irrigation management of onion and spinach. HortScience 44:421-425.
  • Leskovar, D.I., K. Crosby and J.L. Jifon. 2009. Impact of agronomic practices on phytochemicals and quality of vegetable crops. Acta Horticulturae, 841, 317-322.
  • Crosby, K., J.L. Jifon, K.S. Yoo and D.I. Leskovar. 2009. Novel vegetable cultivars from TAMU- improving human health benefits, flavor and productivity. Acta Horticulturae, 841, 499-502.
  • Jifon, J., Lester, G., Crosby, K. and D. Leskovar. 2009. Improving the quality attributes of melons through modified mineral nutrition. Acta Horticulturae, 841, 499-502.
  • Wen, Y, Piccinni, G., Cothren, J.T., Leskovar, D.I, Rowland, D. and A. Kemanian. 2009. Regulated deficit irrigation and cotton production responses in southwest Texas. Proceedings of the USCID 5th International Conference on Irrigation and Drainage: Irrigation and Drainage for Food, Energy and the Environment. Salt Lake City, UT. The U.S. society for irrigation and drainage professionals. pp. 289-300.
  • Leskovar, D. 2009. Roots: The foundation of vegetable growth, yield and quality. 2009 OPGMA Congress, Ohio. Jan. 12, 2009.
  • Leskovar, D. 2009. Effects of pre-harvest cultural strategies on phytochemicals, yield and quality. OPGMA Congress, Ohio. Jan. 13, 2009.
  • Bae, H., Jayaprakasha, G.K., Crosby, K., Leskovar, D., Jifon, J. and B.S. Patil. 2009. A modified method for extraction and quantification of ascorbic acid and capsaicinoids in mature peppers. Texas A & M AgriLife conference, 2009 Student Research Poster Competition.
  • Cooper, S. and D.I. Leskovar. 2009. Selective feeding on artichoke foliage by white-tailed deer in Texas. 7th International Symposium on artichoke, Saint Pol de Leon, France, June 17.
  • Leskovar, D. Shinohara, T. and B. Patil. 2009. Integrated approaches for annual artichoke production in southwest Texas. 7th International Symposium on artichoke, Saint Pol de Leon, France, June 17.
  • Niu, G., Rodriguez, D., Crosby, K, Leskovar, D. and J. Jifon. 2009. Rapid screening for salt tolerance in specialty peppers. HortScience 44, 1021.
  • Niu, G., Rodriguez,Leskovar, D., Crosby, K. and J. Jifon. 2009. Drought tolerance of specialty chile peppers. HortScience 44, 1021-1022.
  • Piccinni,. G., Ko, J., Marek, T. and D. Leskovar. 2009. Crop coefficients specific to phonological stages for evapotranspirations-based irrigation management of onion and spinach. HortScience 44, 1022.
  • Jifon, J., Crosby, K. and D. Leskovar. 2009. Water relations, yield, and fruit quality of grafted, field-grown watermelons. HortScience 44, 1172.
  • Leskovar, D.I., Shinohara, T., Agehara, S. Cooper, S. K. Yoo and B. Patil. 2009. Development of cultural strategies for artichoke production in Texas. EN-4. VFIC Conference, Austin.
  • Shinohara, T. 2008. Development of management practices for artichoke production in.
  • Bae, H., Jayaprakasha, G.K., Crosby, K., Leskovar, D., Jifon, J. and B.S. Patil. 2009. Variation in ascorbic acid, capsaicinoids, and flavonoids of different pepper cultivars. EN-8. VFIC Conference, Austin.
  • Bang, H., Kim, S., Leskovar, D.I. and S.R. King. 2009. Flesh color inheritance and gene interaction in watermelon. G-B 6. VFIC Conference, Austin.
  • Crosby, K., Yoo, K.S., Leskovar, D.I. and J. Jifon. 2009. Developing vegetables with enhanced antioxidant levels. G-BN 10. VFIC Conference, Austin.
  • Bae, H., Jayaprakasha, G.K., Crosby, K., Leskovar, D., Jifon, J. and B.S. Patil. 2009. Cultivars and growing conditions influence ascorbic acid contents in peppers. Proceedings of the 12th Texas Pepper Conference. p.13.
  • Piccinni, G., Leskovar, D., Harman, W., Marek, T. And B.L. Harris. 2009. Precision Irrigators Network: On-Farm Research and Demonstration to Evaluate Irrigation Scheduling Tools in the Wintergarden and Texas High Plains. Texas AgriLife Reserch and Extension Report, pp. 92.
  • Websites and news releases. 2009. http://www.sciencedaily.com/releases/2008/11/081103170645.htm
  • Websites and news releases. 2009. http://www.bio-medicine.org/biology-news-1/New-hybrid-plants-could-pr ompt-more-prodigious-pepper-production-in-Southwest-5715-1/
  • Websites and news releases. 2009. http://www.greenhousecanada.com/content/view/1406/38/Texas Gardener. Jan. 09. Artichoke and Cardoon
  • Websites and news releases. 2009. http://esciencenews.com/articles/2008/11/03/new.hybrid.plants.could.p rompt.more.prodigious.pepper.production.southwest
  • Websites and news releases. 2009. http://southwestfarmpress.com/news_archive/southwest-peppers-1211/


Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: We continue with an artichoke field experiment addressing deficit irrigation (50 and 75% ETc) and nitrogen rates and their impact on yield and quality. We also evaluated conventional and blends of slow release N fertilizers at medium and high rates in onion and spinach yield and quality. To complement field experiments, an incubation study designed to determine soil-ammonium and nitrate mineralization from slow release nitrogen sources and urea was conducted in the greenhouse under controlled moisture conditions. An experiment designed to screen artichoke cultivars with green and red color head-types under a subsurface drip with mulch and bare soil was finalized. We also screened experimental and commercial hybrids of traditional and specialty peppers, included new Texas AgriLife jalapenos, serranos, cayenne, poblano, bells, habaneros and anchos. Several invited presentations (2 international, 4 national, 2 state, and 2 regional) depicted our work in artichoke strategies and phytonutrients, environmental stress tolerance in vegetable transplants, and seedling establishment. Results were also disseminated through news media and websites in the state and nationwide. PARTICIPANTS: Individuals: Giovanni Piccinni, Kevin Crosby, Kilsun Yoo, John Jifon, Smiljana Goreta, Beny Aloni, Juan Fernandez, Shinsuke Agehara. Partner Organization: Texas Water Development Board, Texas Department of Abgriculture, Vegetable and Fruit Improvement Center, Georgia Pacific, Valent BioSciences, AgroFresh, USDA. . Collaborators: Constanzo Farm (artichoke grower), South Cross Vegetable Transplants, Cargil Produce, Speedling Inc. (Alamo, TX and Nipomo, CA) Training: graduate students Togo Shinohara, Alvaro Proano, Libbie Johnson. Undergraduate training: 4 TARGET AUDIENCES: Vegetable growers, seed industry and transplant nurseries. Commodity groups, spinach producer board, water groups. Members of the Seed and Stand Establishment working gropus (ASHS), American Society of Plant Growth Regulators and American Chemical Society. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
In artichoke, irrigation was more effective than N rates to optimize yield. The yield reduction by 50% ETc was associated with a decrease in head number and weight. The highest yield was obtained with 100% ETc and 120 kg/ha N. This study also showed significant responses on artichoke quality, with deficit irrigation improving phenolic content in artichoke heads, but with significant yield losses. In onions, slow release N sources (Nfusion 50% and Nitamin) increased chlorophyll content compared to control. Overall there was a tendency for Nitamin, Nfusion 30% and Nfusion 50% to have a lower percentage of bulb to shoot during early development, but differences were minimal during late development. Among all N sources, Nfusion 50% at 112 kg/ha or Nitamin at 168 kg/ha were the best treatments. From the incubation study, a rapid decline in ammonium occurred within the first 2 weeks, with a reduced release between 5 and 8 weeks, and almost no release past 8 weeks up to 11 weeks. For nitrates, the four N sources follow a quadratic response with a rapid release during the first 4 weeks of incubation, reaching a plateau at about 7-8 weeks. From the artichoke cultivar screening under drip, total marketable yields were highest for Green Globe Improved, Concerto, Madrigal, Imperial Star and Lorca (range 15,400 to 14,200 kg/ha). Similar head size was also higher for those cvs. (range 377 to 284 g/head). Plastic mulch increased yields by 11% and water use efficiency by 36% as compared to bare-soil. New mild habanero hybrids produced from plants selected at Uvalde are potential materials for release due to its vigor, concentrated fruit set, bacterial and virus resistance.

Publications

  • Leskovar, D.I., S. Goreta, J.L. Jifon, S. Agehara, T. Shinohara and D. Moore. 2008. ABA to enhance water stress tolerance of vegetable transplants. Acta Hort., 782:253-264.
  • Crosby, K.M., J.L. Jifon and D.I. Leskovar. 2008. Genetic improvement of early root vigor in melon (Cucumis melo L.) to enhance stand establishment. Acta Hort., 782:273-278.
  • Jifon, J.L., Crosby K.M., Leskovar D.I. and Miller M. 2008. Possible Physiological Mechanisms for Resistance to Vine Decline Diseases in Grafted Watermelons. Acta Hort. 782:329-334.
  • Crosby K.M., Jifon J.L., and Leskovar D.I. 2008. Agronomic Strategies for Enhancing Health-Promoting Properties and Fruit Quality of Vegetables. pp. 392-411. In: F.A. Tomas-Barberan and M.I.Gil (eds) Improving the health-promoting properties of fruit and vegetable products. CRC Press, Boca Raton, Fla.
  • Crosby, K., J. Jifon and D.I. Leskovar. 2008. Chujuc, a new powdery mildew resistant western-shipper melon with high sugar and β-carotene content. HortScience 43(6):1-3.
  • Leskovar, D.I. 2008. Editor, Proceedings of the 4th International Symposium on Seed, Translant and Stand Establishment of Horticultural Crops. Acta Horticulturae # 782.
  • Chun, C., Lee, J-M, Leskovar, D.I., Halmer, P., Wang, C., and C. Lee. 2008. Proceedings of the International Symposium on Seed Enhancement and Seedling Production Technology. Acta Horticulturae # 771.
  • Leskovar, D. 2008. ABA to enhance environmental stress tolerance in vegetable transplants' Proceedings of the Amer. Soc. Plant Growth Regulators. Monterrey, CA.
  • Leskovar, D.I., K.M. Crosby, and K.S. Yoo. 2008. Deficit irrigation strategies to enhance phytochemicals and quality in vegetable species. AGFD 109, Division of Agricultural and Food Chemistry, Cornucopia, Fall 2008.
  • Crosby, K.M., D.I. Leskovar and K.S. Yoo. 2008.Genetic improvement of vegetable beneficial phytochemical concentrations. AGFD 112, Division of Agricultural and Food Chemistry, Cornucopia, Fall 2008.
  • Jifon, J., Lester, G., Leskovar, D.I., Patil, B. and K. Crosby. 2008. Improving fruit phytochemical contents through foliar potassium (K) nutrition. AGFD 113, Cornucopia, 236th ACS National Meeting, Philadelphia, PA.
  • Agehara, S. and D.I. Leskovar. 2008. Impact of 1-MCP on fruit set and yield of seedless watermelon . HortScience 43(4)1084.
  • Leskovar, D., Agehara, S. and K.S. Yoo. 2008. Yield and phytochemical responses to deficit irrigation and plant population of spinach. HortScience 43(4)1030-1031.
  • Crosby, K., Leskovar, D., Jifon, J. and K.S. Yoo. 2008. Characterization of novel traits and cultivar development in habanero-type peppers (Capsicum chinense Jacq.). HortScience, 43(4)1051.
  • Bang, H., Kim, S., Leskovar, D. and S. King. 2008. Inheritance and interaction of flesh color genes among canary yellow, pale yellow, and red watermelon. HortScience, 43(4)1050.
  • Leskovar, D.I., S. Agehara, S. Goreta, J.L. Jifon and K.Crosby. 2008. ABA: A tool to improve stress tolerance in pepper transplants, 19th International Pepper Conference, New Jersey, p. 22.
  • Leskovar, D.I., Piccinni,G., Agehara, S. and Kil Sun Yoo. 2008. Deficit irrigation and plant population impact on yield, quality and phytochemicals in spinach. Proceedings International Spinach Conference, p. 8.


Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: Deficit irrigation strategies in combination with nitrogen rates were evaluated on yield, quality and phytoutrient content of selected vegetable crops in Southwest Texas. In artichoke, we repeated the 2006 experiment under similar conditions (three deficit irrigation and four nitrogen rates) except that the N application was done through a fertigation system. In spinach we determined yield, leaf quality and carotenoid content in response to deficit irrigation and plant population. Spinach seeds were planted at plant populations, ranging from 497,000 to 1,129,000 seeds/ha and three irrigation regimes were imposed with a low pressure drip system (LPS). In onions we compared the impact of slow release nitrogen fertilizer (Nitamin) with the conventional urea ammonium nitrate (UAN) on yield under the LPS and subsurface drip systems (SDI). To improve stand establishment, we evaluated four melon grafted combinations in response to exogenous ABA under optimum and deficit irrigation. A new experiment was established to screen artichoke cultivars with green and red color head-types under a subsurface drip with mulch and bare soil. Cultivars are: Blanca de Tudela, Concerto, Green Globe, Green Globe Improved, Harmony, Imperial Star, Lorca, Madrigal, and Opal. At the growers level, soil moisture was monitored with sensors placed at three depths in the following crops and farms: onion: Knippa, linear system; Batesville, furrow system; Frio, center pivot; Uvalde, drip irrigation, and Uvalde LPS drip; artichoke: D'Hanis, linear system; pepper: Hondo, drip irrigation, and Uvalde, drip irrigation; and cabbage: Uvalde, linear system. Three invited presentations at international conferences (100+ attendance) depicted our work in the area of agronomic strategies, phytochemicals and quality of vegetable crops, and on methods to enhance stress tolerance of vegetable transplants. Results from this project were also disseminated through newsmedia and websites nationwide. A News released by the Associated Press featured our artichoke research activities and was released at the regional, state and national levels. New crop guidelines for this crop were also developed. PARTICIPANTS: Individuals: Giovanni Piccinni, Kevin Crosby, Kilsun Yoo, John Jifon, Smiljana Goreta, Beny Aloni, Juan Fernandez, Shinsuke Agehara. Partner Organization: Texas Water Development Board, Texas Department of Abgriculture, Vegetable and Fruit Improvement Center, Georgia Pacific, Valent BioSciences. Collaborators: HEB, Jerry Van Damme (artichoke grower), South Cross Vegetable Transplants, Cargil Produce, Speedling Inc. Training: graduate students Togo Shinohara, Alvaro Proano and Libbie Johnson. Undergraduate training: 2 TARGET AUDIENCES: Vegetable growers, seed industry and transplant nurseries. Commodity groups, water groups. Members of the Seed and Stand Establishment working gropus (ASHS).

Impacts
In artichoke, the highest marketable yield was obtained with the combination of 100 % ETc and 60 kg N/ha. In spinach marketable yield was not reduced by deficit irrigation at 75% ETc. Petiole length, a quality component for the processing canning industry, was significantly reduced at 50% ETc. Ascorbic acid, beta carotene, lutein, and neoxanthin, consistently increased with deficit irrigation, while violaxanthin content was unaffected by the irrigation treatments. In onion, soil N (ammonium and nitrate) content was not significantly affected by irrigation rates in the LPS but was lowest with subsurface drip and deficit irrigation. Spinach yield responses were similar across the irrigation treatments; results that were expected since excess rainfall during 2007 compensated for crop evapotranspiration rates. In melon grafted transplants, ABA reduced photosynthesis and stomatal conductance within a day after application but transplants recovered from the inhibitory effects of ABA and regained all the physiological parameters to the control level after 3 days. ABA-treated plants appeared to gain protection against a prolonged drought stress period. Integrating efficient drip irrigation and nitrogen fertilizer strategies will lead to optimal quality and yield of high cash-value vegetable crops in Southwest Texas. Screening and selection of artichoke cultivars with improved quality, phytochemical content and adaptability to low/high temperatures and drought conditions may provide an expanded growing season for this new crop.

Publications

  • Proano,A.S., S. Agehara, J. Jifon, G. Piccini, K.S.Yoo and D.I. Leskovar. 2007. Impact of low-pressure drip irrigation and N slow-release fertilizer on onion yield and quality. HortScience 42:1002.
  • Shinohara, T., S. Agehara, K.S.Yoo, and D.I. Leskovar. 2007. Irrigation and nitrogen management to improve yield and nutritional quality of artichoke. FAV Health, Houston, p. 114.
  • Waters, J., H. Bang, A. Davis, D.I. Leskovar and S.R. King. 2007. Semi-quantitative measurement of carotenoid development in four watermelon colors: A discussion of the impact of ploidy and other genetic factors. HortScience. 42(3): 439.
  • Goreta, S., Jifon, J., and D.I. Leskovar. 2007. Physiology and growth of pepper seedlings exposed to transient drought stress is differentially altered by antitranspirants. Journal of the American Society for Horticultural Sciences 132(5):603-610.
  • Bang, H., Kim, S., Leskovar, D. and S. King. 2007. Development of a codominant CAPS marker for allelic selection between canary yellow and red watermelon based on SNP in lycopene B-cyclase (LCYB) gene. Molecular Breeding 20:63-72.
  • Falkenberg, N.R., Piccinni, G., Leskovar, D., Cothren, J.T. and C.M. Rush. 2007. Remote sensing of biotic and abiotic stress for irrigation management of cotton. Review paper. Agricultural Water Management 87:23-31.
  • Crosby, K.M., J.L. Jifon, B. Villalon, and D.I. Leskovar. 2007. TAM Dulcito, a new, multiple virus-resistant sweet jalapeno pepper. HortScience 42: 1488-1489.
  • Leskovar, D.I., Goreta, S., Piccinni, G. and K.S. Yoo. 2007. Strategies for globe artichoke introduction in South Texas. Acta Horticulturae 630:157-163.
  • Leskovar, D.I., H. Bang, S.L. Kim, K.S. Yoo, S.R. King and K. Crosby. 2007. Environmental and genetic factors on carotenoids and quality in watermelon fruits. Acta Horticulturae 744:233-241.
  • Yoo, KS, Pike, L., Patil, B.S., Leskovar, D., Crosby, K. and S. King. 2007. Challenges of phytochemical analysis and its application in developing new fruits and vegetables with improved health benefits. Acta Horticulturae 744:101-105.
  • Crosby, K.M., Jifon, J.L., and D.I. Leskovar. 2007. Agronomy and the nutritional quality of vegetables. In: Improving the health promoting properties of fruit and vegetable products. Woodhead Publishing. p. 392-411.
  • Crosby, K., Jifon, J., and D. Leskovar. 2007. Pacal orange casaba, and Chujuc western shipper cantaloupe: two new melon cultivars from the Texas Agricultural Experiment Station. HortSci. 42(4): 1013.
  • Piccinni, G., J. Ko, D. Leskovar, A. Kemanian, T. Gerik, 2007. EPIC simulation to manage irrigated crops. Farming Systems Design p. 69-70.
  • G. Piccinni, J. Ko, A. Wentz, D. Leskovar, T. Marek, T. Howell. 2007. Determination of Crop Coefficients for Irrigation Management of Crops. 28th Annual International Irrigation Show, San Diego, CA, December 9-12.706-719.
  • Leskovar, D.I. 2007. Impact of agronomic strategies on phytochemicals and quality of vegetable crops. 2ndInternational Symposium on Human Health Effects of Fruits and Vegetables, FAV2007 Health, Houston, TX. p.77.
  • Leskovar, D.I. and S. Agehara. 2007. Post-harvest 1-MCP dip method maintains pre-harvest fruit quality in cantaloupe. HortScience 42:883.
  • Leskovar, D., Agehara, S., Piccinni, G. and K.S. Yoo. 2007. Impact of deficit irrigation and plant population on yield, leaf quality and carotenoid content of spinach. FAV Health , Houston, TX. p. 119-120.
  • Shinohara, T., S. Agehara, K.S.Yoo, H.Bae, and D.I. Leskovar. 2007. Irrigation and nitrogen impact on artichoke yield head quality and phenolics. HortScience 42:879.


Progress 01/01/06 to 12/31/06

Outputs
Deficit irrigation, irrigation systems and cropping strategies were evaluated on economically important vegetable crops in the Wintergarden region of Southwest Texas. In spinach we investigated deficit irrigation rates under subsurface drip (SDI), low-pressure drip systems (LPS), and Center Pivot with variable plant populations. Plant populations up to 1.16 million seeds/ha showed maximum yield under well-watered regimes, particularly under the LPS, while leaf quality (yellowing) decreased with deficit irrigation. In onions we determined the impact of a slow release nitrogen fertilizer (Nitamin) compared to the conventional urea ammonium nitrate (UAN) on growth, yield and phytochemical content under the LPS and SDI systems. Plants treated with Nitamin had significantly less lodging and high chlorophyll content than those with UAN. More large and valuable size bulbs resulted with high irrigation rates and Nitamin, while maintaining lower soil nitrates compared to UAN. In collaboration with the Agronomy program, onion crop coefficients are being developed based on phenological stages. Yield and fruit quality of specialty peppers differed in response to nitrogen rates. Overall, optimum yield was measured with 134 kg N/ha in jalapenos, chile and paprika peppers. We continue screening and selecting individual plants or advance breeding lines of ancho and habanero peppers with improved size, high vigor, phytochemical content and high adaptability for water-restricted areas. Stand establishment and production strategies that include deficit irrigation, nitrogen rates and cultivars are also being investigated on growth, yield and phytochemical content of globe artichokes. The goal of this project is to determine the potential feasibility of artichoke production in the region. This year, high yield with less tip-burn in artichoke heads resulted from well-watered regimes and medium rates of nitrogen fertilization (less than 120 kg N/ha). To improve fruit quality in cantaloupe fruits, we evaluated 1-MCP dipping methods and determined optimum rates and dipping times. Our results showed that cantaloupe fruit quality, such as firmness, was significantly improved by post-harvest dip application of 1-MCP. In conjunction with researchers at TAES-Weslaco, an on-going study in grafted melons is evaluating physiological responses and yield of cultivar Caravelle grafted on commercial Cucurbita rootstocks.

Impacts
The integration of efficient drip irrigation practices with slow release nitrogen fertilizers are key management practices for optimal quality and yield of high cash-value vegetable crops. Selection of improved specialty pepper and artichoke cultivars with improved quality, phytochemical content and adaptability to water-restricted regions can provide new opportunities to increase market shares and profitability for growers in Southwest Texas regions. Post-harvest applications of plant growth regulators such as 1-MCP have the potential to maintain pre-harvest fruit quality and prolong the shelf life of melons.

Publications

  • Piccinni, G., D.I. Leskovar. 2006. Crop Simulation and Crop Evapo-Transpiration for Irrigation Management of Corn and Spinach. ASA-CSSA-SSSA Annual Meeting, Indianapolis, IN.
  • Crosby, K., J. Jifon and D.I. Leskovar. 2006. Breeding for improved early root vigor in melon (Cucumis melo L.). 4th ISHS International Symposium on Seed, Transplant and Stand Establishment. San Antonio, Texas. p.29.
  • Proano, A., Leskovar, D.I., Agehara, S. and K.S. Yoo. 2006. Impact of low-pressure drip irrigation and N slow-release fertilizer on onion yield and quality. National Allium Research Conference. College Station, Texas. p. 47.
  • Leskovar, D.I., Goreta, S. and J.A. Franco. 2006. Impact of AVG pre-harvest spray and soil injection on yield and quality of melon. HortScience 41(5):1249-1252.
  • Kahn B. and D. I. Leskovar. 2006. Cultivar and plant arrangement effects on yield and fruit quality of bell pepper. HortScience 41(7):1-6.
  • Yoo, K.S., K. Crosby and D. Leskovar. 2006. Differences in onion pungency due to cultivars, growth environment, and bulb sizes. Scientia Horticulturae 110:144-149.
  • Piccinni, G., D. Supercinski, D. Leskovar, B. Harris and C.A. Jones. 2006. Rio Grande Basin water conservation project. Transactions on Ecology and the Environment. Book Chapter, pp. 321-330.
  • Goreta, S. and D.I. Leskovar. 2006. Screening spinach cultivars for white rust resistance and bolting. HortTechnology 16(1) 162-166.
  • Jifon J.L., K.M. Crosby, and D.I. Leskovar. 2006. Physiological characteristics of grafted muskmelon grown in Monosporascus cannonballus-infested soil in South Texas. Cucurbitaceae 06:23-30.
  • Crosby, K.M., Lester, G.E. and D.I. Leskovar. 2006. Genetic variation for beneficial phytochemical levels in melons (Cucumis melo L.). Cucurbitaceae 06:70-77.
  • Leskovar, D., Agehara, S. and S. Goreta. 2006. 1-MCP preharvest spray application to synchronize harvest and improve fruit quality of cantaloupe. HortSci 41:1015.
  • Bang, H.J., Kim, S., Leskovar, D.I., Davis, A. and S. King. 2006. Duplication of the phytoene synthase gene in the carotenoid biosynthetic pathway of watermelon. HortSci 41:1007.
  • Leskovar, D. I., S. Goreta, G. Piccinni, K.S. Yoo, G. Piccinni and S. Agehara. 2006. Crop strategies impact on yield and head quality components of globe artichoke in Southwest Texas. HortSci 41:986.
  • Piccinni, G., Marek, T. and D. I. Leskovar. 2006. Crop simulation and crop evapo-transpiration methods for irrigation management of spinach. HortSci 41:971.
  • Crosby, K. and D. Leskovar. 2006. TAM Ben Villalon and TAM Valley Hot- two new pepper cultivars from the Texas Agricultural Experiment Station at Weslaco. HortSci 41:1072.


Progress 01/01/05 to 12/31/05

Outputs
Water conservation strategies were evaluated on several vegetable crops using a Center pivot and drip irrigation systems. Deficit irrigation under Center pivot in combination with increased plant population showed the potential to increase yield and water savings, without adversely affecting leaf quality in spinach. Farmers in the Wintergarden area are currently implementing this practice. Deficit irrigation is also being evaluated with subsurface drip (SDI) and low-pressure systems (LPS) in spinach and short-day onion cultivars. Irrigation applications are based on climatic parameters and specific crop coefficients developed in the area in collaboration with the Agronomy program. In triploid watermelon, deficit irrigation reduced yields but not fruit firmness and brix compared to a well-irrigated treatment. In peppers, deficit irrigation significantly reduced marketable yield due a decline in the fruit number in ancho and jalapeno types. The feasibility for the production of globe artichoke under SDI is being investigated in the region. Irrigation rates did not affect yield, water use efficiency or head quality. Cultivars Emerald, Imperial Star and Experimental Red were earlier than Green Globe and Purple Romagnia. The best yield was for cv. Imperial Star, while largest head weight was for cv. Green Globe. Total fibers, crude protein and phenolic compounds concentration depended on cultivar, whereas total sugar concentrations in the edible part of the head were similar among cultivars. Head weight, percentage of heart and crude protein concentration decreased, whereas total fibers content increased as harvesting season progressed. We continue screening and selecting individual plants or advance breeding lines of ancho and habanero pepper as well as watermelons with improved size, high vigor, disease tolerance and high adaptability for water-restricted areas. In melon, we determined the effects of 1-MCP rate and timing applied as pre-harvest spray on harvest synchrony, marketable yield, and fruit quality. We are also comparing 1-MCP dip and spray methods on soluble solid content and firmness. 1-MCP appeared to slightly delayed maturity but synchronized harvest. Harvest synchrony can improve labor scheduling, which is a critical cost for melon production. Our one year data also showed that 1-MCP increased fruit set when applied during the reproductive development in triploid watermelon.

Impacts
Developing efficient irrigation strategies and screening for improved genotypes, improved quality and with adaptability to semi-arid conditions can create new opportunities to increase market shares and profitability for growers in south Texas. Pre-harvest applications of plant growth regulators have the potential to improve growth, fruit set, and harvesting efficiency in cucurbit species.

Publications

  • Lee, J., Crosby, K.M., Pike , L.M., Yoo, K. and D.I. Leskovar. 2005. Impact of genetic and environmental variation on development of flavonoids and carotenoids in pepper (Capsicum spp.). Scientia Horticulturae 106:341-352.
  • K.M. Crosby, D.I. Leskovar and K.S. Yoo. 2005. TAM Mild Habanero, a low pungency Habanero pepper. HortScience 40 (2) 490-491.
  • Leskovar, D.I., G. Piccinni, and D. Moore. 2005. Deficit irrigation and plant population effects on leaf quality and yield of spinach. HortScience 40(4):1095.
  • Piccinni, G., D.I. Leskovar and T. Marek. 2005. Determination of crop coefficients (Kc) and water use of spinach and onion. HortScience 40(4): 1095.
  • Bang, H.J., Kim, S., Leskovar, D.I. and S.King. Genotype analyses of fruit color using a molecular marker in watermelon. 2005. HortScience 40(4):1114.
  • Crosby, K.M., D.I. Leskovar, and K.Yoo. 2005. TAM Dulcito and Tropic Bell- Two new sweet peppers with enhanced beneficial phytochemical levels. HortScience 40(4):1020.
  • Jifon, J., K. Crosby and D.I. Leskovar. 2005. Gas exchange and chlorophyll fluorescence responses of closely-related pepper genotypes to high temperature stress. HortScience 40(4): 1076.
  • Falkenberg, N.R., Piccinni, G., Leskovar, D., Cothren, J.T. and C.M. Rush. 2005. Remote sensing for site-specific management of biotic and abiotic stress in cotton. Proceedings of the Beltwide Cotton Conference, 1095-1099.
  • Bang, H.J. 2005. Ph.D. Environmental and genetic strategies to improve carotenoids and quality in watermelon. (Thesis).
  • Leskovar, D.I., Piccinni G., Bang, H., Moore, D.J.and K.S. Yoo. 2005. Deficit Irrigation: Approaches to improve yield and quality of vegetable crops in water- restricted regions. Interdrought II Conference, Rome. (In press)
  • Piccinni, G. and D. I. Leskovar. 2005. Development of phenological-stage-specific crop coefficients (Kc) to manage deficit irrigating in agricultural production systems. Interdrought II Conference, Rome. (In press)
  • Leskovar, D.I., Bang, H., King, S.; Kim, S.; Crosby, K. and K.S. Yoo. 2005. Environmental and genetic factors affecting carotenoids and quality in watermelon fruits. FAV, Health. Quebec City, Canada. (In press).
  • Leskovar, D.I. and G. Piccinni. 2005. Yield and leaf quality of processing spinach under deficit irrigation. HortScience 40:1868-1870.


Progress 01/01/04 to 12/31/04

Outputs
Water conservation strategies were evaluated with a center pivot and subsurface drip irrigation in several vegetable species. In spinach, we demonstrated the possibility to grow a crop with a 75% crop evapotranspiration (ETc) saving a minimum of 25% of water per season without reducing yields and leaf quality. Another study with varying plant population and deficit irrigation showed that marketable yields were not reduced by deficit irrigation at the range of 200-300,000 seeds/acre, but water use efficiency was significantly higher for 50% ETc compared to 100% ETc. In conjunction with the Agronomy program, crop coefficients were also developed in spinach based on phenological stages. In pepper, fixed lines of habanero, poblano, jalapeno and serrano pepper were compared to commercial standards for yield and quality under full and deficit irrigation (100% and 50% ETc). Overall, deficit irrigation decreased yield in jalapenos, habaneros and poblanos, but not in serrano types. Morphological and physiological shoot adaptation responses to exogenous abscicic acid (ABA) were also investigated during transplant maturity in poblano or 'ancho' peppers. ABA controlled stem growth up to 8 days after treatment, and drench application to roots was more effective than foliar treatments. Leaf photosynthesis decreased when ABA was applied as drench or foliar at higher concentrations, but this response was reversible. Root application of ABA imparted drought stress tolerance. In red-, orange-, and yellow-fleshed diploid and triploid watermelon, deficit irrigation reduced the individual fruit weight and size in the early planting, but did not reduced yield significantly. Soluble solids content (SSC) and firmness were not affected by irrigation rate. SSC varied across cultivars and increased with maturity and triploids were firmer than diploid cultivars. Both diploid and triploid red-fleshed cultivars had significantly higher carotenoid content than orange- and yellow-fleshed cultivars. Lycopene was the major carotenoid (more than 65%), followed by prolycopene, and B-carotene. The inheritance of carotenoids associated with specific flesh color (white, canary yellow, yellow, salmon yellow, light red, and red) in watermelon are being evaluated by analyzing segregating populations. In poblano and habanero peppers, advanced breeding materials and plant introductions were selected in 2004. Emphasis is given to TAES 466, TAES 467 (virus resistance), and plant introductions with resistance to TSWV. In conjunction with TAES Weslaco, we collaborated in the development and released of 'TAM Mild Habanero,' a high yielding, low pungency, yellow-orange Habanero pepper.

Impacts
Vegetable production in the Wintergarden is strictly regulated on water use. Developing efficient irrigation strategies and screening improved genotypes with adaptability to semi-arid conditions, and improved quality can provide 'branded products' for growers in south Texas, and consequently create new opportunities to increase market shares and profitability.

Publications

  • Bang, H., D.I. Leskovar, D.A. Bender, and K. Crosby. 2004. Deficit irrigation impact on lycopene, soluble solids, firmness and yield of diploid and triploid watermelon in three distinct environments. Journal of Horticultural Science & Biotechnology 79(6): 885-890.
  • Piccinni, G., K. Kolenda, T.H. Marek, D.A. Dusek, T.A. Howell, and D.I. Leskovar. 2004. Determination of crop coefficients and water use of corn, spinach and onion. 49th Annual Meeting, Crop Society of America, Seattle, WA. 6210 (abstract).
  • Leskovar, D.I., G. Piccinni, D.J. Moore, and K. Kolenda. 2004. Deficit irrigation and plant population interaction for processing spinach cultivars. National Spinach Conference, San Antonio, Texas (abstract).
  • Leskovar, D.I., H.J. Bang, K. Crosby, N. Maness, J.A. Franco and P. Perkins-Veazie. 2004. Lycopene, carbohydrates, ascorbic acid, and yield components of diploid and triploid watermelon cultivars are affected by deficit irrigation. Journal of Horticultural Science and Biotechnology Vol. 79 (3) 75-81.
  • Leskovar, D.I., M. Cantamutto, P. Marinangelli and E. Gaido. 2004. Comparison of direct-seeded, bareroot, and various tray seedling densities on growth dynamics and yield of long-day onion. Agronomie 24:1-6.
  • Leskovar, D.I. D.J. Moore, L. Johnson, J.Loaiza, and G. Piccinni. 2004. Water Conservation Systems and Strategies for Poblano Pepper Production. HortScience 39:852 (abstract).
  • K. Crosby, D. Leskovar and K. Yoo. 2004. TAM Mild Habanero: a low-pungency Habanero variety for South Texas. ASHS-Austin. HortScience 39: 765 (abstract).
  • Bang, H., S. Kim, D.I. Leskovar and S. King. 2004. Differential expression of carotenoid biosynthesis genes among different colored flesh in watermelon. HortScience 39(4): 869 (abstract).
  • Bang, H., D.I. Leskovar and K.S. Yoo. 2004. Carotenoids and quality of watermelon as affected by deficit irrigation and growing season. HortScience 39(4): 803 (abstract).
  • Falkenberg, N. R., G. Piccinni, J.T. Cothren, D.I. Leskovar, C.M. Rush, and K.Kolenda. 2004. Remote sensing for site-specific management of biotic and abiotic stress in cotton. 49th Annual Meeting, Crop Society of America, Seattle, WA. 6333 (abstract).
  • Leskovar, D. and G. Piccinni. 2004. Impact of deficit irrigation and cultural strategies on leaf quality and marketable yield of spinach. 17th International Lettuce and Leafy Vegetables. Montreal, Canada. p.15.
  • Stocco, G., M. Cantamutto, P. Marinangeli,E. Gaido, E. Ayastuy and D. Leskovar. 2004. Efecto del trasplante de cebolla en golpes triplanta sobre la forma de los bulbos. SAO Annual Meetings, (abstract).


Progress 01/01/03 to 12/31/03

Outputs
Irrigation from underground aquifers is an important economic component for crop production in southwest Texas. In addition, there is an increased consumer demand for high quality vegetables in the U.S. Our goal is to save water, maximize production, and improve quality of economically important vegetable crops with deficit irrigation. In watermelons, 50 % evapotranspiration rates (ETc) reduced yield in three Texas locations. Firmness and soluble solids content was higher with deficit irrigation in triploid watermelon. We confirmed that lycopene content did not decline with 75 % ETc. The genetic component for lycopene in watermelon fruits appears to have a stronger influence than the environment. In processing spinach, we concluded a two-year study under a Center pivot system. Highest water use efficiency resulted in cv. ASR 157 at 75 % ETc. Our results indicate that it is possible to reach a 25% water savings in one season, without reducing yields when using vigorous cultivars. In poblano peppers, we evaluated water conservation strategies with subsurface drip (SDI) in a rural-urban environment near San Antonio. SDI with white mulch had a 2.4 fold yield increase and 76 mm water savings compared to furrow. Fruit vitamin C content was not affected by irrigation; however, mature red fruits had a 3.6 fold increase compared to mature green fruits. In habanero pepper, yield increased by 60 % under deficit irrigation for TAES-466 compared to the commercial cv. Peto. In bell pepper, single- and double-row arrangements of a fixed population were compared with two or five cultivars in Texas and Oklahoma for effects on yield and fruit quality. A single row arrangement resulted in higher U.S. No. 1 fruit yields than double-rows, despite an increased potential for cull fruit production with single rows. In order to improve stand establishment and reduce transplant shock during early development, ABA or ABA-analog exogenous root applications were evaluated on bell pepper after transplanting. Seedlings evidenced wilting with ABA 200 ppm, but no visible stress was detected on transplants treated with ABA-analog at 20 ppm. Leaf area and stress rates were significantly reduced with ABA-analog. Growth regulators were also tested for enhancing fruit color in peppers. ABA and LPE (lysophosphatidyl ethanolamine) did not affect total yield compared to ethephon or control, but marketable weight of red color fruits increased with ABA. In triploid watermelon, we evaluated solid matrix priming (SMP) to improve seed germination and vigor. SMP with hydrogen peroxide was effective to promote early germination rate. Fungicides modified seedling root structure and branching. We continue identifying TAMU and commercial cultivars with improved yield, quality, and adaptability to Texas environments. Two commercial mid-day onions were selected for large scale evaluations during 2004. In habanero and poblano peppers, we selected individual plants based on fungal and virus resistance, vigor and fruit characteristics. In melons, a TAES genotype with high sugars and high productivity was identified.

Impacts
Deficit irrigation applied with subsurface drip or Center pivot systems is a critical strategy to reach significant water savings in one season. Water savings can be further increased if deficit irrigation is integrated with improved stand establishment systems, drought tolerant and vigorous genotypes. Deficit irrigation will reduce yield, but it is most likely that physical and chemical quality attributes would be less affected.

Publications

  • Leskovar, D.I., Bang, H., Kolenda, K., Franco, J.A. and Perkins-Veazie, P. 2003. Deficit irrigation influences yield and lycopene content of diploid and triploid watermelon. Acta Hort. 628:147-151.
  • Kahn, B., D.I. Leskovar, B. Bostian, and C. Maness. 2003. Proceedings of the 22nd Annual Horticulture Industries Show, Springdale, Arkansas, pp. 109-111.
  • Bang, H., D.I. Leskovar, D. Bender, and K. Crosby. 2003. Impact of deficit irrigation and environment on lycopene and quality of watermelon. HortScience 38:816 (abstract).
  • Crosby,K., K. Yoo, D. Leskovar and L. Pike. 2003. Impact of environment, irrigation and maturity on ascorbic acid concentrations of diverse pepper (Capsicum spp.) germplasm lines grown at two Texas locations. HortScience 38:664 (abstract).
  • Crosby, K., J. Lee, K. Yoo, D. Leskovar and L. Pike. 2003. Genetic variation in pepper for flavonoid and carotenoid contents. HortScience 38:1286 (abstract).
  • Leskovar, D.I. and G. Piccinni. 2003. Deficit irrigation improves yield and quality of processing spinach. HortScience 38:720 (abstract).
  • Leskovar, D.I. and G. Piccinni. 2003. Impact of deficit irrigation on yield and quality of spinach. National Spinach Conference, Fayeteville, Arkansas, Nov. 20-21, p.17.
  • Falkenberg, N., R. Piccinni, G., Cothren, J., T., Troxclair, N., and D.I. Leskovar. 2003. Remote sensing for site specific management of biotic and abiotic stress in cotton. ASA-CSSA-SSSA Annual Meeting Abstracts [CD-ROM computer file].
  • Grange, S., D.I. Leskovar, L.M. Pike, and B.G. Cobb. 2003. Seed coat structure and oxygen-enhanced environments to improve germination of triploid watermelon. J. Amer. Soc. Hort. Sci. 128:253-259.


Progress 01/01/02 to 12/31/02

Outputs
Vegetable production in southwest Texas regions is strictly regulated on water use. In addition, consumer demand for high quality and nutritious vegetables has increased. The project emphasizes how deficit irrigation and crop strategies affect growth, yield, and quality of economically important vegetables. In watermelon, limited irrigation directly reduced yield, but triploids were less affected than diploid fruits. Genetic and environmental variability for lycopene content and sugar composition was found among diploid and triploid watermelons. Deficit irrigation was evaluated at three Texas locations with subsurface drip (SDI) and black mulch. At the Uvalde and Weslaco locations, lycopene content increased with maturity and was not reduced with limited irrigation (75 or 50% PET). Limited irrigation was also evaluated in three processing spinach cultivars under a Center pivot system. The percentage of yellow leaves increased significantly with 50% PET irrigation rate. This response was more evident for `CXF 3665'. High irrigation (100% PET) increased stem growth, which is an undesirable characteristic for canning. Highest marketable yield were obtained for `ARS 157' at either 100% or 75% PET rates. In the absence of pest and diseases this cultivar appears promising under limited irrigation, with a 25% water savings. In bell pepper `Red Knight', 100% PET rate applied with SDI under black mulch did not improve yields compared to lower rates during summer. However, limited irrigation increased the % of fruits with blossom end rot (BER). Under Center pivot without mulch, 60% PET rate reduced early production of marketable fruits, but fancy fruits (weight and number) increased at 100% PET. Summer pruning peppers allowed a second crop - ratooning - for the fall. This technique allowed the production of `Poblano' peppers, a potential new crop for Texas. The objective of this practice is to decrease PET due to a reduced canopy size, and to allow an efficient re-direction of photosynthates to the harvestable portion of the plants (e.g. flowers and fruits). Under limited irrigation, pruned plants had a vigorous re-growth, normal fruit development, less BER, an increase in the harvest index and more fancy fruits. In cantaloupes, we evaluated the effects of timing and method of application of aminoethoxyvinylglycine (AVG) on yield and quality components. After two years of experimentation, we concluded that pre-harvest application of AVG either with drip or spray did not enhance yield, fruit netting, firmness or sugar content after storage. In triploid watermelons, seed priming techniques to improve seed germination, seedling vigor and stand establishment are being investigated. In short-day onion genotypes, cell-grown transplants significantly decreased the growing period in the field improving bulb quality and flavor compared to direct seeding. We continue identifying TAMU genotypes and commercial cultivars of short-day onions, melon, peppers and spinach with improved yield, superior quality characteristics, and tolerance to environmental and biological stresses.

Impacts
Limited irrigation applied with efficient irrigation systems in combination with improved stand establishment methods and drought tolerant genotypes can save water significantly. These strategies will help speed up the development of vegetable products with high flavor, nutrition and quality characteristics. We expect to develop unique `branded' products that will provide a competitive advantage, with the potential to enhance Texas market share and profitability.

Publications

  • Leskovar, D.I. and K. Kolenda. 2002. Strobilurin + acibenzolar -S-methyl controls white rust without inducing leaf chlorosis in spinach. Annals of Applied Biology 140:171-175.
  • Franco, J.A. and D.I. Leskovar. 2002. Root dynamics of muskmelon transplants as affected by nursery irrigation. Journal of the American Society for Horticultural Science 127:337-342.
  • Leskovar, D.I. and K. Kolenda. 2002. Spinach cultivar screening for white rust and bolting - Season 2001. UREC-02-012.
  • Leskovar, D.I., K. Kolenda, K.S. Yoo, and L.M. Pike. 2002. Containerized onion transplants: I. A strategy to enhance yield and size. UREC-02-014.
  • Leskovar, D.I., K.S. Yoo, and L.M. Pike. 2002. Containerized onion transplants: II. Flavor enhancement. UREC-02-015.
  • Leskovar, D.I., K. Kolenda, and J. Pena. 2002. Containerized onion transplants: III. Yield response to increased seedling density. UREC-02-016.
  • Leskovar, D.I., H.J. Bang, K. Kolenda, J.A. Franco, and P. Perkins-Veazie. 2002. Deficit irrigation influences yield and lycopene content of 2x and 3x watermelon. UREC-02-017.


Progress 01/01/01 to 12/31/01

Outputs
Vegetable production regions in southwest Texas are strictly regulated on water use. In addition, demand for high quality and nutritious vegetables has increased. A management system for short day onion is being developed. Components of this system include containerized transplants or direct seeding, subsurface drip, irrigation rates, and improved cvs. `TG 1015Y', the newly developed `Legend', and `Texas Early White' (TEW). We have determined that pungency was lower and brix was higher for transplants than direct seeding. Pungency level ranges were 2.8-3.9 umoles/ml (Legend), 3.4-4.1 (TG1015Y) and 5.3-5.7 (TEW). Quality was not affected by irrigation, except that water use efficiency was higher with limited irrigation (applied after plants were fully established) and with subsurface drip at 15 cm depth. Transplants were more productive with an average yield increase of 40% compared to direct seeding. The yield increase was greatest for `Legend'. Transplants also had larger bulb sizes and higher water use efficiency than direct-seeded plants. Total yield increased by 7% with drip placed at 15 cm depth, with no significant differences between rates. A subsequent study compared yield and quality of transplanted onion `Legend' produced from multiple seedlings using flats with 242 cells. Our results showed that by growing three seedlings per cell it may be possible to reduce the cost per plant and obtain similar yields and larger bulb diameters than direct seeding. Containerized onion transplants can provide an immediate and complete field establishment, enhance onion flavor, and produce uniform high-value bulb sizes, thus increasing profit potential for the grower. Deficit irrigation was also explored on yield, fruit quality and lycopene content of red-fleshed diploid (2n), and triploid (3n) or seedless watermelon cultivars. Deficit irrigation reduced watermelon yield by 36% and 50% at 0.75 ET and 0.50 ET rates, respectively. Triploid plants had higher yield than diploid watermelons. Lycopene levels were highly affected by cultivar, and were generally higher in triploids (range 60-66 ug/g fresh weight basis). In triploid watermelons, we are also evaluating seedling vigor using seed conditioning treatments such as solid matrix priming, which incorporates extra-fine, hydrophilic particles into the seed coat to facilitate uniform water uptake into the seed and to promote seed germination. Limited irrigation is also being implemented in combination with a ratooning and pruning system for summer and fall production of high-value red bell peppers. Summer pruning could be a low capital procedure to increase pepper yields (premium fruits) in warm climates where the growing season is long enough to produce a ratoon crop. We have identified commercial cultivars of specialty colored peppers and spinach with superior yield, stress and disease resistance. Similarly, TAMU pepper and melon breeding lines were also screened for phytochemical content and general adaptability to drought stress. In spinach, we determined the high effectiveness of Strobilurin + Actigard for the control of white rust disease and to improve the overall leaf quality.

Impacts
Efficient irrigation and crop management strategies in combination with improved genotypes for vegetable species, including short-day onions, specialty peppers, and seedless watermelons, will save water and speed the development of products with unique flavor and quality characteristics. These products may provide a competitive advantage, with the potential to enhance market share and profitability.

Publications

  • Baker, J.T., D.I. Leskovar, V.R. Reddy, and F.J. Dainello. 2001. A simple phenological model of muskmelon development. Annals of Botany. 87:615-621.
  • Franco, J.A., S. Banon, J.A.Fernandez, and D.I. Leskovar 2001. Effect of nursery regimes and establishment irrigation on root development of Lotus creticus seedlings following transplanting. The Journal of Hort. Sci. & Biotech. 76(2)174-179.
  • Leskovar, D.I. and K. Kolenda. 2001. Trifloxystrobin+acibenzolar-S-methyl controls white rust without inducing leaf chlorosis in spinach. HortScience 36:439.
  • Wang, T., L. Sistruck, D.I. Leskovar and B.G. Cobb. 2001. Relationship between seed reserves and germination in triploid watermelon. HortScience 36:511.
  • Leskovar, D.I., J.C. Ward and A. Meiri. 2001. Comparison of irrigation and stand establishment systems on yield, quality and water use efficiency of cantaloupe. HortScience 35:1238-1240.
  • Kahn, B.A. and D.I. Leskovar. 2001. A ratoon cropping system for fall bell pepper production. HortScience 36:897-899.


Progress 01/01/00 to 12/31/00

Outputs
Scanning electron micrographs of diploid and triploid watermelon seeds showed that the endotesta, the seed cavity surrounding the embryo and folded cotyledons are three distinctive morphological characteristics that may inhibit seed germination or reduce seed vigor of triploids. Experiments on irrigation strategies and stand establishment on short-day onion cultivars showed that yields and Brix were higher, and pungency was lower for transplants compared to plants established by direct seeding. Water use efficiency (WUE) was highest for `Legend' onion transplants when applied at 0.5 ET rate with drip placed at 15 cm depth. Drip placement, irrigation rates, and cultural practices in combination with pruning are currently being evaluated on specialty colored bell peppers. Aminoethoxyvinylglycine (AVG), an ethylene inhibitor, was investigated in cantaloupe fruit quality. Plants responded to AVG spray as a time-sensitive response, delaying the onset of fruit abscission when AVG was sprayed 14 days before harvest (DBH). Yield was enhanced significantly when AVG was applied through drip 21 DBH, however pre- or post-harvest flesh firmness and sugar content were unaffected. Acibenzolar-S-methyl (Actigard) in combination with trifloxystrobin (Flint) was confirmed to be highly effective for the control of white rust disease when applied preventively in spinach. Breeding lines and/or commercial cultivars with superior yield, stress and disease resistance were identified in spinach, pepper and cabbage.

Impacts
Information on seedling and plant physiological/morphological adaptation responses to water, temperature and disease stresses will help develop specific technologies and sustainable production systems to enhance yield and quality of irrigated vegetable crops in semi-arid environments.

Publications

  • Leskovar, D.I., L.Stein, and F. Dainello. 2000. Planting systems influence growth dynamics and quality of fresh market spinach. HortScience 35:(7).
  • Grange, S., D.I. Leskovar, L. Pike, and G. Cobb. 2000. Excess moisture and seed coat alteration influence germination of triploid watermelon. HortScience 35:(7).
  • Stover, E.W., P.J. Stoffella, S.A. Garrison, D.I. Leskovar, D.C. Sanders, and C.V. Vavrina. 2000. Bloom and postbloom applications of NAD/NAA mixture have minimal effects on yield and fruit size of field-grown tomatoes and peppers.HortScience 35:(7).


Progress 01/01/99 to 12/31/99

Outputs
Experiments on water conservation strategies showed that water use efficiency (WUE) and yield of melons was higher for direct seeded than transplants, but the latter had improved soluble solid content. This response was independent of drip position between 5 and 20 cm depth. In triploid and diploid watermelons, drip irrigation was more efficient when positioned at 20 compared to 5 cm under bare-soil conditions. Drip with plastic mulch increased WUE by 28% compared to bare-soil, and above 200% compared to furrow systems. Total fruit yields were not reduced by short or long 1.0/0.5ET cycles and 0.5ET compared to constant 1.0ET irrigation rate. Triploid seed germination was very sensitive to conditions of excess moisture, possibly due to a combination of physiological and morphological defects. The high variability of the air gap in the seed cavity in triploids could also be related to the poor seed germination and uniformity. Watermelon transplant root/shoot growth of several related genotypes are being studied in response to irrigation systems and media water holding capacity. The results from a cropping sequence study for bell peppers showed that summer pruning offers an opportunity for increased fall production of premium fruit. Superior genotypes with high levels of disease and stress resistance were identified in spinach. Similarly, superior cabbage, onion and carrots genotypes are being evaluated for yield and horticultural characteristics. In spinach, a new systemic acquired resistance-type fungicide was efficient to reduce the % of infected leaves with white rust.

Impacts
(N/A)

Publications

  • Leskovar, D.I., V. Esensee, and H.Belefant-Miller. 1999. Pericarp, leachate, and carbohydrate involvement in thermoinhibition of germinating spinach seeds. J. Amer. Soc. Hort. Sci. 124:301-306. Leskovar, D.I. and C.S.Vavrina. 1999. Onion growth and yield are influenced by transplant tray cell size and age. Sci. Hort. 80:133-143. Leskovar, D.I., J.C. Ward and A. Meiri. 1999. Water stress, timing and irrigation systems for watermelons and cantaloupe. Proc. 5th Internat. Conf. on Desert Development. Vol 1: 631-639.


Progress 01/01/98 to 12/31/98

Outputs
Water conservation strategies and irrigation timing are being investigated in melons in the Winter Garden of southwest Texas. Constant or abrupt water deficit prior to or after fruit set decreased yield and fruit number, but not fruit size and color of ripe watermelons. Triploid or seedless plants exposed to frequent cycles of water deficit were acclimated to tolerate subsequent drought stress and set more and smaller fruits than hybrids. An experiment in cantaloupe confirmed that the cropping system with transplants, drip, and plastic mulch had the highest water use efficiency. Beta sweet carrot, a new genotype developed by Texas A&M, was evaluated for quality and bolting, and to establish a production calendar in spring and fall season. Over this first year, most plants bolted in the spring (fall plantings) but none in the fall (summer plantings). Selecting non- bolting material for spring production continue. Fruit set in poblano peppers were not improved by an exogenous auxin. Crop sequence in bell peppers is being compared in the spring (unpruned and pruned systems) and fall. In spinach, a new systemic acquired resistance-type fungicide was more effective in controlling white rust than traditional fungicides. Fresh market and processing spinach with genetic resistance to white rust, yield and low bolting were identified. Similarly, several superior cabbage, carrot, and onion genotypes are being evaluated for multiple stress resistance, yield, quality, and horticultural characteristics.

Impacts
(N/A)

Publications

  • Leskovar, D.I. 1998. Root and shoot modification by irrigation. HortTech.8(4):510-514.
  • Leskovar, D.I. 1998. Basic and applied aspects of seed biology. HortScience 33:172-173.


Progress 01/01/97 to 12/31/97

Outputs
Water conservation strategies are being investigated in vegetable crops in the Winter Garden of southwest Texas. Irrigation systems with varying input levels, drip depth position, and stand establishment affected growth, yield, and quality of cantaloupes. Plants on sub-surface drip with plastic mulch had higher water use efficiency (WUE) than plants on furrow with or without mulch. Irrigation synchronized with specific growth stages had more influence on watermelon fruit set and early yield than on leaf and vine growth. WUE and yield of spinach were higher under sub-surface drip and sprinkler compared with furrow irrigation systems. Cantaloupe, onion, cabbage, pepper and tomato seedlings were subjected to three N-rates and two irrigation systems in the greenhouse and field. Root/shoot growth and transplant shock responses to irrigation and N were both species and cultivar dependant. Genetic resistance of fresh market and processing spinach were evaluated for temperature stress and white rust disease. Similarly, commercial and experimental cabbage, carrot, and onion genotypes are being evaluation for adaptability in terms of multiple stress resistance, yield, quality, and horticultural characteristics. Several superior genotypes have been identified.

Impacts
(N/A)

Publications

  • Santos, J.R., and D.I. Leskovar. 1997. Interference from broccoli residue on Brassica germination and seedling growth. J. Amer. Soc. Hort. Sci. 122:715-720.
  • Leskovar, D.I. 1997. Root and shoot growth of vegetable crop transplants: modification by irrigation. 5th National Symposium on Stand Establishment. p. 36-39.


Progress 01/01/96 to 12/30/96

Outputs
Reductions in the supply of high quality irrigation water from underground aquifers is affecting production in the Winter Garden of southwest Texas. Investigations were conducted to determine how growth, yield, and quality are affected by synchronizing irrigation and specific growth stages in watermelons grown with subsurface drip. Irrigation rates with varying evapotranspiration (ET) rates were applied at three growth stages. Changes in irrigation rates during reproductive development influenced more fruit setting and early yield than leaf and vine growth. Total marketable fruit yield ranged from 90.3 to 80.9 MT/ha when 881mm and 577mm of irrigation water, respectively, were applied. However, plants irrigated with constant 0.5 ET demonstrated greater water use efficiency than those with 1.0 ET. Irrigation systems that included furrow, surface drip, and subsurface drip, stand establishment and mulching were evaluated on cantaloupes. Transplanted canteloupes with mulch and drip irrigation positioned at 10cm depth produced 44% higher yields and had higher water use efficiency (88 vs 187 liters of water needed per kg of fruits) than on furrow systems. Similar trends were measured for direct seeded plants. Current work is focused on deficit irrigation strategies using drip, sprinkler, and furrow systems on processing and fresh market spinach. Information on water use will assist farmers in designing management strategies that minimize risks due to uncertainties in weather.

Impacts
(N/A)

Publications

  • Leskovar, D.I. and A.K. Boales. 1996. Azadirachtin: potential use against lepidoptera insects and to increase marketability in cabbage. HortSci. 31:405-409.
  • Leskovar, D.I., J.C. Ward and A. Meiri. 1996. Water stress timing and irrigation systems for cantaloupes and watermelons. 5th International Conf. Desert Develop.(In Press).


Progress 01/01/95 to 12/30/95

Outputs
Drip irrigation and stand establishment systems designed to conserve water, improve quality and maximize yields of canteloupes and watermelons are being studied. During spring, watermelons produced a total marketable fruit yield of 84,000 to 63,000 lbs. when 22 inches and 14 inches of irrigation water were applied. However, plants subjected to less water were more water use efficient, since they produced more fruit per unit water applied. Cantaloupe total yields were in between 794 and 915 boxes/ac, when 4 inches of irrigation water was applied through the drip systems under polyethylene mulch. Furrow systems produced in between 540 boxes to 677 boxes when 12.3 inches were applied, while 470 boxes were produced on furrows pre-irrigated with 6 inches. Future work will be aimed at the timing of water stresses and changes in water quality. Spinach genotype sensitivity to thermodormancy (>30C) and osmoconditioning treatments to avoid seed dormancy, and spinach plant population and mulching systems to produce a tube-pack fresh spinach product are being investigated. We continue with efficacy control studies on insect pests in cabbage and spinach and with genotype selection and adaptability tests for pest, disease and environmental stresses on spinach, tomatoes, cantaloupes and watermelons.

Impacts
(N/A)

Publications


    Progress 01/01/94 to 12/30/94

    Outputs
    Cropping systems to tolerate field stresses and to reduce plant and product variability are being developed. Spinach genotypes expressed differential sensitivity to supraoptimal temperatures for germination. The seed coat acted as a physical barrier and source of inhibitors for germination. The role of oligosaccharides and seed osmoconditioning techniques to improve spinach germination are being assessed. In onions, 10- to 12-weeks-old containerized transplants had high survival rates, uniform root growth, and more uniform bulb size than younger transplants. Pungent pepper transplants had higher yields than direct-seeded plants, response that was more pronounced when selected genotypes with multiple stress resistance were used at high population densities. Plant residues from cole crops used extensively in crop rotation systems affected subsequent crop growth. For example, broccoli leaf extracts were more potent to inhibit cauliflower and cabbage seedling growth than stems and roots residues. Biological insect control using neem-plant extracts was effective against major pests in cabbage, reducing head damage. Genotype selection and adaptability for pest, disease and environmental stresses continue on pepper and spinach. Root/shoot adaptation responses to subsurface drip irrigation systems used to conserve water and improve production efficiency will be investigated.

    Impacts
    (N/A)

    Publications

    • LESKOVAR, D.I. and M.C. BLACK. 1994. White rust infection and leaf chlorosis in relation to crop strategies in spinach. Env. Exp. Bot. 34(4), xxx-xxx.
    • LESKOVAR, D.I. and R.R. HEINEMAN. 1994. Greenhouse irrigation systems affect growth of `TAM-Mild Jalapeno-1' pepper seedlings. HortScience 29(12):1470-1474.
    • LESKOVAR, D.I., J.R. SANTOS and A.K. BOALES. 1994. Potential use of azadirachtin for controlling lepidopterous pests in cabbage. TAES PR. 5151.
    • LESKOVAR, D. I., P. J. STOFFELLA and D. J. CANTLIFFE. 1994. Transplant production systems influence growth and yield of fresh market tomatoes. J. Amer. Soc. Hort. Sci. 119:662-668.
    • LESKOVAR, D.I. and P.J. STOFFELLA. 1995. Vegetable seedling root system: morphology, development, and importance. HortScience (Accepted).


    Progress 01/01/93 to 12/30/93

    Outputs
    Extreme high temperatures may cause seed thermodormancy. in spinach, we found that the pericarp imposes physical restriction and served as a source of chemicals inhibiting embryo growth. The characterization and role of oligosaccharides in the establishment or releasing of dormancy during imbibition and desiccation is being studied. Reduction of plant growth variability in the field may lead to improve produce quality. Transplant methods in peppers and onions are being investigated on plant morphological components, transplant `shock', maturity and yield. Sustainable management strategies are evaluated to develop appropriate technologies. In cabbage, biomass accumulation, leaf nitrogen and yields were optimized at medium irrigation and low N levels. Assessment of broccoli plant extracts on the allelopathy response of cole crops is being investigated. In spinach, the use of genotypes with high level of resistance to white rust disease, superior leaf color, growth and yield has been identified under optimum irrigation and chemical protection levels. Crop adaptability for pest, disease and environmental stresses continue on pepper and onion genotypes. The efficacy of azadirachtin (a natural insecticide) for the control of lepidopterous insects are being evaluated in vegetables. Conditions for alternative cropping systems such as daikon seed production were established for SW Texas.

    Impacts
    (N/A)

    Publications

    • LESKOVAR, D. I. and D. J. CANTLIFFE. 1993. Comparison of plant establishment method, transplant or direct-seeding, on growth and yield of bell pepper. J. Amer. Soc.,Hort. Sci. 118:17-22.
    • ESENSEE, V., D.I. LESKOVAR and A.K. BOALES. 1994. Methanol treatment of cabbage, cauliflower, cantaloupe, onions and pepper. J. Hort. Science (Submitted).
    • LESKOVAR, D.I. and M.C. BLACK. 1994. White rust infection and leaf chlorosis in relation to crop strategies in spinach. Env. Exp. Bot. (In revision).
    • LESKOVAR, D. I., P. J. STOFFELLA and D. J. CANTLIFFE. 1994. Transplant production systems influence growth and yield of fresh market tomatoes. J. Amer. Soc. Hort. Sci. (in-press).


    Progress 01/01/92 to 12/30/92

    Outputs
    a) In SW Texas, spinach is seeded in early Fall at temperatures higher than 20(degree)C. At 30(degree)C, seed germination decreased 60%, however the embryo germinated if deprived of the pericarp. Genotypes exhibited different seed coat characteristics and inhibitor (ABA) levels. b) Pungent Capsicum transplants had an unbalanced root/shoot growth but earlier and higher yields than direct-seeded plants. Greenhouse sub-floatation irrigation systems improved early root growth and water use efficiency, reducing transplant `shock' in the field. c) Broccoli field crop residue may release chemicals causing germination and growth inhibition to the subsequent crop (allelopathy). Cauliflower grown after broccoli reduced root and shoot growth over time. Allelopathic symptoms were not improved by increasing fertilization. d) In 1992, higher yields for daikon seed production (1,085 kg/ha) were obtained with 45 kg/ha of N for October plantings. In 1993, root/shoot growth, seed quality and seed yield are being evaluated in response to plant arrangement and plant population. e) Crop adaptability and management strategies for yield, quality, pest, disease and stress resistance continue on pepper, spinach and cole crops. In spinach, at medium and high irrigation levels, ARK-354 maintained lower disease rate, less chlorosis, greater root growth and higher yield than ACX-5044.

    Impacts
    (N/A)

    Publications

    • LESKOVAR, D.I. and CANTLIFFE, D.J. 1993. Comparison of plant establishment method, transplant or direct-seeding, on growth and yield of bell pepper J. Amer. Soc. Hort. Sci. 118(1).
    • LESKOVAR, D.I. and CANTLIFFE, D.J. 1992. Pepper seedling growth response to exogenous abscisic acid. J. Amer. Soc. Hort. Sci. 117:389-393.
    • LESKOVAR, D.I. and HEINEMAN, R.R. 1992. Root elongation, shoot growth and water status of jalapeno pepper as influenced by transplant irrigation. Nat. Symp. Stand Establishment Hort. Crops. Proc. 101:241-246.
    • SANTOS, J.R. and LESKOVAR, D.I. 1992. Growth response of cole crops to the allelopathic influence of broccoli. Nat. Symp. Stand Establishment Hort. Crops. Proc. 101:151-156.


    Progress 01/01/91 to 12/30/91

    Outputs
    a) A study on the relationship of temperature (15 to 35(degree)C) and germination inhibition in spinach genotypes was initiated in the laboratory. b) Transplant root/shoot morphological and physiological adaptation before and after transplanting are being evaluated in response to transplant watering systems and age in jalapeno peppers. Growth and yield of transplants and direct-seeded cayenne peppers is investigated in the field. Transplants had an unbalanced dry matter partitioning between roots and shoots, but earlier and higher productivity than direct-seeded plants. This response was unaffected by spacing. Comparisons of planting methods, transplants and direct-seeding, on root/shoot growth were also initiated in spring 1991 in four melon cultivars. c) Early root and shoot growth, head physiological disorders and yield of broccoli and cabbage will be characterized and evaluated in the field (2nd year) in response to boron and sulfur. In 1990, yields were greater for sulfur than boron single application. d) Daikon plants are being evaluated for their growth and development, seed quality and seed yield in response to N levels at various environments. e) Crop adaptability tests are being conducted on pepper, spinach and cauliflower. Evaluation will be aimed for yield/quality, market (fresh or industry), pest, diseases and stress resistance.

    Impacts
    (N/A)

    Publications

    • No publications reported this period.