Source: UNIVERSITY OF PUERTO RICO AT MAYAGUEZ submitted to
A STUDY OF CROP ADAPTATION TO ACID SOIL CONDITIONS AND ALUMINUM TOXICITY USING COMMON BEAN (PHASEOLUS VULGARIS L.) AS A MODEL CROP
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0200976
Grant No.
2004-34135-14893
Project No.
PR00TSTAR-102
Proposal No.
2004-05454
Multistate No.
(N/A)
Program Code
AH
Project Start Date
Sep 1, 2004
Project End Date
Aug 31, 2007
Grant Year
2004
Project Director
Munoz, M. A.
Recipient Organization
UNIVERSITY OF PUERTO RICO AT MAYAGUEZ
P. O. BOX 9000
MAYAGUEZ,PR 00681
Performing Department
Crops and Agroenvironmental Sciences
Non Technical Summary
Common bean (Phaseolus vulgaris L.) is one of the most important legume crops of the world. The selection of bean varieties adapted to acid soil conditions of the tropics is necessary to ensure economic stability to many farmers who cannot afford liming applications. Bean varieties with the capacity to tolerate acid soil conditions will also improve yields in areas where liming is no feasible due to high acidity conditions in the subsoil. The study herein proposed will evaluate tolerance and adaptability of selected bean varieties to acid soil conditions and aluminum toxicity. The degree of tolerance to aluminum toxicity will be correlated to the capacity of the bean varieties to produce and secrete organic acids and the efficiency of such process to neutralize exchangeable aluminum. Field experimental data on plant growth, nutrient uptake and yield will be collected and correlated to the capacity of selected bean cultivars to secrete organic acids under growth chamber conditions. The results of this study will provide common bean and other legume breeding programs with valuable insights for the development of strategies for selection for tolerance to soil acidity problems. The evaluation of performance of bean lines under acid soil conditions should lead to the development of more appropriate recommendations to farmers in Puerto Rico and the Caribbean region who have soil acidity problems in their farms.
Animal Health Component
25%
Research Effort Categories
Basic
50%
Applied
25%
Developmental
25%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1020110200040%
2021410102030%
2051410102030%
Goals / Objectives
Evaluate tolerance of Caribbean common bean (Phaseolus vulgaris L.) germplasm to soil acidity and aluminum toxicity under field conditions. Evaluate the capacity of beans to produce and secrete organic acids, the efficiency of this process in neutralizing aluminum toxicity and how it correlates with field data.
Project Methods
Fifteen common bean varieties will be evaluated for aluminum tolerance and soil acidity factors under field conditions. The soil at the experimental site is a very acid Ultisol with high levels of exchangeable aluminum. Three levels of exchangeable aluminum (0, 50 and 80 percent reduction) will be established by liming. The crop will be evaluated for fresh and dry matter production, yield, nutrient uptake, and aluminum uptake. Data will be also collected on deficiency and toxicity symptoms. Soil samples will be collected from 0-20 and 20-40 cm depths at planting and at 30 and 60 days after planting. The soil will be evaluated for pH, exchangeable aluminum, available phosphorus and exchangeable basic cations. The capacity of bean varieties to secrete organic acids will be evaluated under laboratory conditions. Pre-germinated seedlings will be placed in nutrient solutions containing aluminum concentrations of 0, 25 and 50 M. The aluminum treatments will be replicated three times. The root exudates will be monitored for 48 hours, replacing and collecting the solution every 12 hours. The solution containing root exudates will be frozen, lyophilized, redissolved, purified using cation and anion exchange columns, and analyzed by anion exchange chromatography. Identification and quantification of organic acids will be achieved by comparison of component retention times in standard solutions and peak integration to fit into standard curves for quantification. Root growth inhibition by aluminum concentration will be evaluated and compared to control plants. The performance of bean varieties under field conditions will be correlated to their capacity to secrete organic acids, measured under laboratory conditions.

Progress 09/01/04 to 08/31/07

Outputs
A growth chamber study was conducted to determine the effect of three Al3+ concentrations (0, 25 and 50 microMolar) on root development of bean cultivars and on the capacity of the cultivars to secrete organic acids. The bean cultivars Morales, Salagnac 90A, Batt 477, Vax 1, and Arroyo Loro were used in the study. The bean seedlings were grown in nutrient solutions and were exposed to the Al3+ solution concentrations for 48 hours. Organic acid exudation by Morales variety was measured by using an anion exchange chromatograph Dionex IC 20, equipped with an EG 40 Eluent Generator. The analytical column was Dionex S 11-HC 4 x 250 mm (P#052960), coupled to a Guard Column AG11-HC 4 x 50 mm (P#052962). The presence of citrate and oxalate was detected in the solution when the seedlings were exposed to 25 and 50 microMolar Al3+ solutions, but that was not the case for the 0 microMolar treatment. The citrate peak was observed in around 33 minutes retention time. The citrate conductivity peak was more intense at the higher aluminum concentration. The intensity of the peak conductivity when Morales bean seedlings were exposed to 25 microMolar Al3+ in solution was 2.25 microS, and increased to 3.32 microS when exposed to 50 microMolar Al3+. This finding indicates that larger amounts of citrate are produced by bean roots as the concentration of Al3+ in solution is increased. Average root length between Al3+ treatments ranged from 2.0 to 2.6 cm, and number of secondary roots ranged from 16 to 19. The effect of acid soil conditions and high levels of soil exchangeable Al3+ on grain and dry matter yield of the bean variety Morales were evaluated in Corozal soil (very-fine, parasesquic, isohyperthermic Typic Hapludults). The range of soil exchangeable Al3+ studied was between 0.08 cmolc kg-1 at a soil pH of 6.88, to 3.84 cmolc kg-1 at a soil pH of 4.78. These ranges of pH and exchangeable Al3+ were attained by liming the soil at rates of 0, 5, 10 and 20 t ha-1. At a soil pH of 4.78 and a soil exchangeable Al3+ concentration of 3.84 cmolckg-1, the mean grain yield of the variety Morales was 890 kg ha-1. At a soil pH of 5.17 and a soil exchangeable Al3+ concentration of 1.67 cmolckg-1, the mean grain yield of the variety Morales was 1,279 kg ha-1.

Impacts
The capacity of bean varieties in the presence of high levels of exchangeable Al3+ can be used as criteria for the selection of varieties tolerant to Al3+ toxicity in acid soils. The capacity of Morales variety to tolerate acid soil conditions and high levels of exchangeable Al3+ make it suitable for planting in acid soils without the need of liming or with minimum liming. Also this variety can be used in future breeding initiatives to develop new varieties tolerant to soil acidity conditions.

Publications

  • Labayen, P. E. 2007. Evaluacion de Lineas de Habichuelas (Phaseolus vulgaris L.) en un Suelo de Corozal Bajo Condiciones de Acidez y Toxicidad de Aluminio. Master Thesis, University of Puerto Rico, Mayaguez.
  • Munoz M. A., P. E. Labayen, J. S. Beaver, A. G. and F.R. Roman. 2007. Performance of Morales bean variety (Phaseolus vulgaris L.) under acid soil conditions and high exchangeable Al3+. Caribbean Food Crops Society Meeting, San Jose, Costa Rica.


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

Outputs
The effect of soil pH and exchangeable Al3+ content on the yield of the bean variety 'Morales' was evaluated in Corozal soil (Ultisol). Exchangeable Al3+ at the experimental site ranged from 0.02 cmolc kg-1 at a soil pH of 6.45 to 3.44 cmolc kg-1 at a soil pH of 4.90. Bean yield increased from 890 kg ha-1 to 1,322 kg ha-1 when soil pH was increased by liming from 4.90 to 5.50. This increase in pH decreased soil exchangeable Al+3 from 3.44 cmolc kg-1 to 0.40 cmolc kg-1. When exchangeable Al3+ content was in the range of 3.44 cmolc kg-1 to 0.94 cmolc kg-1 no significant differences in yield were observed. A second experiment was established at the same site to evaluate the same yield parameters. No significant differences in yield were observed. However, a significant increase in Al concentration in leaves was observed as exchangeable Al3+ in the soil increased. Also a decrease in Ca concentration in bean leaves was observed. The data suggests that the bean variety Morales has a tolerance degree to high exchangeable Al3+ concentrations.

Impacts
Aluminum toxicity in the soil surface can be easily corrected by liming, if a good and affordable lime source is available. However, aluminum toxicity in the subsoil is very difficult to correct and very often not economically viable. The evaluation and selection of bean varieties tolerant to aluminum toxicity will provide farmers with a valuable tool to overcome this problem and allow them to obtain higher yields and make a more efficient use of agricultural marginal land.

Publications

  • Munoz M. A., J. S. Beaver, F. R. Roman and S. Ortega Achurry. 2006. Citrate exudation by bean cultivars, a potential mechanism to overcome Al3+ toxicity. Caribbean Food Crops Society Meeting, San Juan, Puerto Rico.
  • Labayen, Pedro E., M. A. Munoz, J. S. Beaver and F. Roman. 2006. Evaluacian de lineas de habichuela (Phaseolus vulgaris L.) en un suelo Corozal bajo condiciones de acidez y toxicidad de aluminio. Puerto Rican Society for Agricultural Sciences. 10 November 2006, Pichi's Convention Center, Guayanilla Puerto Rico.


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

Outputs
A growth chamber study was conducted to determine the effect of three Al3+ concentrations (0, 25 and 50 micro molar) on the capacity of bean cultivars to secrete organic acids. Bean cultivars Morales, Salagnac 90A, Batt 477, Vax 1 and Arroyo Loro were used in the study. The bean seedlings were grown under growth chamber conditions and were exposed to the Al3+ solution concentrations for 48 hours. Root exudates were qualitatively analyzed by using anion exchange chromatography. The presence of citrate and oxalate was detected in the solution when the seedlings were exposed to 25 and 50 micro molar Al3+ solutions, but that was not the case for the 0 micro molar treatment. The citric acid conductivity peak was more intense at the higher aluminum concentration. The citrate peak was observed around 33 minutes retention time. The intensity of the conductivity peak when Morales bean seedlings were exposed to 25 micro molar Al3+ in solution was 2.25 micro siemens, and it increased to 3.32 micro siemens when exposed to 50 micro molar Al3+. This indicates that larger amounts of citrate are produced by bean roots as the concentration of Al3+ in solution is increased. A field plot was selected at the Corozal Agricultural Experiment Station located in the mountain region of Puerto Rico. The soil at the site is Corozal clay (Very-fine, parasesquic, isohyperthermic Typic Hapludults). The pH ranged from 3.97 to 5.30, with an average pH of 4.39. Soil exchangeable Al3+ ranged from 1.05 to 8.39 cmolc kg-1, with an average value of 3.53 cmolc kg-1. Four liming treatments (0, 5, 10 and 20 t ha-1) were arranged in a complete randomized block design with four replications. The pH values attained ranged from 4.41 to 5.13. The evaluation of 62 bean cultivars and lines is in progress at the Corozal Agricultural Experiment Station.

Impacts
Aluminum toxicity in the soil surface can be easily corrected by liming if a good and affordable lime source is available. However, aluminum toxicity in the subsoil is very difficult to correct, and this process is often not economically viable. The evaluation and selection of bean varieties tolerant to aluminum toxicity will provide farmers with a valuable tool to overcome this problem and allow them to obtain higher yields and make a more efficient use of marginal agricultural land.

Publications

  • No publications reported this period


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

Outputs
The establishment of experimental soil acidity plots at Corozal Substation is in progress. The soil at the site is classified as Corozal clay (very-fine, parasesquic, isohyperthermic Typic Hapludults). Soil samples collected at 0-20 and 20-40 cm will be analyzed for pH, exchangeable basic cations, exchangeable Al3+, extractable Mn and organic matter. In case no significant level of soil acidity is found in plots at Corozal because of previous liming treatment, soil acidification will be achieved by addition of sulfur to the plots. The reduction in levels of exchangeable aluminum will be achieved by liming. The amount of lime to be added will be determined by the soil incubation method. Preliminary evaluation of the methodology for determination and quantification of organic acids by anion exchange chromatography will be conducted at the soil chemistry laboratory. Standard solutions containing citric acid, oxalic acid and malic acid at different concentrations will be evaluated. The evaluation will include sample preparation, detection limits and assessment of potential interference from nutrients in solution.

Impacts
Aluminum toxicity in the soil surface can be easily corrected by liming, if a good and affordable lime source is available. However, aluminum toxicity in the subsoil is very difficult and often costly to correct. The evaluation and selection of bean varieties tolerant to aluminum toxicity will provide farmers with a valuable tool to overcome this problem and allow them to obtain higher yields and make a more efficient use of agricultural marginal land.

Publications

  • No publications reported this period