Source: UNIVERSITY OF TENNESSEE submitted to
TOBACCO BREEDING AND GENETICS
Sponsoring Institution
State Agricultural Experiment Station
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0196377
Grant No.
(N/A)
Project No.
TEN00106-S
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Jul 1, 2003
Project End Date
Jun 30, 2008
Grant Year
(N/A)
Project Director
Miller, R. D.
Recipient Organization
UNIVERSITY OF TENNESSEE
1331 CIRCLE PARK DR
KNOXVILLE,TN 37916-3801
Performing Department
PLANT SCIENCES
Non Technical Summary
Diseases pose a major problem in profitable burley tobacco production. The development of new cultivars having broad spectrum disease resistance will greatly improve the profitability of Tennessee tobacco farmers. The purpose of this project is to develop new burley cultivars with multiple disease resistance that will provide an effective, cost efficient method of controlling common tobacco diseases.
Animal Health Component
90%
Research Effort Categories
Basic
10%
Applied
90%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2011920108080%
2121920108020%
Goals / Objectives
1. Traditional breeding techniques will be used to develop improved burley tobacco parental lines having resistance to black shank, black root rot, wildfire, fusarium wilt, and tobacco mosaic, tobacco etch, potato virus Y and tobacco vein mottling viruses. 2. These improved parental lines will be utilized to develop new burley tobacco hybrid cultivars that have high yield, good quality, and high resistance to black shank, black root rot, wildfire, fusarium wilt, tobacco mosaic virus (TMV), tobacco etch virus (TEV), and tobacco vein mottling virus (TVMV).
Project Methods
The incorporation of disease resistance into burley tobacco parental lines will be pursued primarily by the pedigree breeding method, with selfing and selection during early generations. The early development and disease screening will be conducted in greenhouses and field nurseries located in Greeneville, TN and Lexington, KY. Individual plants from each population will be selected for agronomic type and resistance to black shank or fusarium wilt resistance in field nurseries through the F5 generation. Seedlings from selfed progeny will be screened for resistance to black root rot, wildfire, and tobacco mosaic, tobacco vein mottling, and tobacco etch viruses in greenhouses. Male sterility will be incorporated into select parental lines from MS TN 90 via a series of 5 backcrosses to the parental line. Appropriate parental lines will be crossed to obtain desired disease resistance in new hybrid cultivars that will be released for commercial burley tobacco production.

Progress 07/01/03 to 06/30/08

Outputs
OUTPUTS: Seven new burley cultivars and seven new dark tobacco cultivars have been released from the Kentucky-Tennessee Tobacco Improvement Initiative (KTTII) within the last five years. Five of the burley cultivars, released in 2004, were the result of industry requests for cultivars with reduced formation of tobacco specific nitrosamines (TSNAs), which are known carcinogens; the new releases were selected for low nicotine to nornicotine conversion and are referred to as low converter or LC cultivars. The LC cultivars do not differ from the original versions for yield, quality, agronomic type or disease resistance; only the chemistry has been altered. KT 204LC, a black shank resistant hybrid burley cultivar, was also released in 2004. It has a high level of black shank resistance and it was the first black shank resistant cultivar with yield potential comparable to the best non-resistant cultivars when grown under disease-free conditions. It has high resistance to black root rot, wildfire, and tobacco mosaic and tobacco vein mottling viruses; it also has medium resistance to tobacco etch virus and low resistance to fusarium wilt. A dark tobacco cultivar, KT D4LC, was released in 2005. In comparison to other dark tobacco cultivars, KT D4LC consistently produces the highest yield and revenue per acre. KT D6LC, the first hybrid dark tobacco cultivar, was released by KTTII in 2006. Although the yield and black shank resistance of KT D6LC is similar to KT D4LC, it has higher resistance to black shank than other commercial dark tobacco varieties; it is also resistant to tobacco mosaic virus, wildfire, and black root rot. NL MadoleLC, KY 171LC, TN D950LC, and ms TN D950LC, low nicotine converter versions of previously released dark tobacco cultivars, were also released in 2006. Like their burley LC counterparts, these LC cultivars do not differ from the original versions for yield, quality, agronomic type or disease resistance; only the chemistry has been altered. KT 206LC, a hybrid burley tobacco cultivar, was released in 2007. In comparison to other burley tobacco cultivars, KT 206LC has superior black shank resistance, moderate tolerance to blue mold, and high yield potential. It also has high resistance to black root rot, wildfire, tobacco mosaic virus, tobacco vein mottling virus, and tobacco etch virus. KT D8LC, a dark tobacco variety was released in 2008. The yield and disease resistance of KT D8LC is very similar to KT D4LC but it is judged by the tobacco industry to have better cured leaf quality and usability. A two year study demonstrated that significant differences exist among commercial burley tobacco varieties that were evaluated for total tobacco specific nitrosamines (TSNA). Over eight trials, KT 204LC consistently produced lower levels of TSNA than did other varieties evaluated. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The University of Tennessee tobacco breeding program is a joint venture with the University of Kentucky. The two programs were merged in 1999 to form the Kentucky-Tennessee Tobacco Improvement Initiative (KTTII), with program funding and responsibilities of the Principal Investigator apportioned between UK and UT on a 60/40 basis. The primary emphasis of the KTTII breeding program involves cultivar and germplasm development, applied research to help growers select and integrate appropriate crop cultivars into specific farm production practices, and providing unbiased information on performance and quality of crop cultivars to producers and associated industries. The program in both States is funded by industry grants and contracts. Grants obtained during 2007-2008 totaled $1,040,000; since KTTII was initiated in 1999 total external funding is $5,047,000. The KTTII tobacco breeding program has a tremendous impact on the farm economy in Kentucky and Tennessee. For the 2007 growing season, KT 204LC, TN 90LC, TN 97LC, KT 200LC, and TN 86LC ranked first, second, fourth, fifth and sixth in terms of seed sales, accounting for over 75% of the total burley tobacco acreage in the United States; KT 204LC alone comprised over 40% of the 2007 US crop. Although KT 206LC was only released in 2007 and was produced by growers for the first time in 2008, preliminary seed sale estimates indicate that KT 206LC and KT 204LC were the top two burley varieties in 2008, comprising approximately 65% of the 2008 domestic burley production. All KTTII cultivars are estimated to comprise over 80% of US burley production in 2008. These cultivars are also planted widely throughout other burley producing countries. TN 90LC has been chosen as the standard cultivar to be used in all CORESTA sponsored international tobacco research. Approximately 20% of the 2007 dark tobacco production in the United States was also produced from KTTII varieties KT D4LC, KT D6LC and TN D950LC.

Publications

  • Miller, R.D. 2008. Variation among burley tobacco cultivars for TSNA content. Paper presented at the 2008 CORESTA Conference, Shanghai, China. 2008 CORESTA Congress Proceedings and Abstracts.
  • Miller R.D. 2008. Breeding for reduced TSNA in burley tobacco. Paper presented at the 62nd Tobacco Science Research Conference, Nashville, TN. Tobacco Abstracts.
  • Miller, R.D. 2008. Improved black shank resistance in burley tobacco varieties. Paper presented at the 43rd Tobacco Workers Conference, Savannah, GA. Tobacco Abstracts.


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

Outputs
KT 206LC, a new hybrid burley tobacco variety developed by the University of Kentucky and University of Tennessee tobacco breeding program, was released in 2007 and will be available for the 2008 growing season. In comparison to existing burley tobacco varieties, KT 206LC has superior black shank resistance, moderate tolerance to blue mold, and high yield potential. It also has high resistance to black root rot, wildfire, tobacco mosaic virus, tobacco vein mottling virus, and tobacco etch virus. Although KT 206LC has performed very well in field trials conducted from 2004-2007, burley growers who are interested in trying the new variety are encouraged to do so only as part of their crop in 2008. KT 206LC is a large, high yielding variety similar to KT 204LC, but both are more difficult to handle than TN 90LC. Although KT 206LC has higher resistance to black shank compared to KT 200LC and KT 204LC, black shank severity and race incidence vary significantly from field to field, and from season to season, so the relative performance of these three varieties may be variable. In fields where race 0 black shank is predominant, KT 206LC performs particularly well. However, in other fields where race 1 is the predominant strain, differences among KT 206LC, KT 204LC and KT 200LC may be less obvious. Metalaxyl should still be used in all fields having a history of black shank. Another important factor for growers to be aware of is that although KT 206LC has improved tolerance to blue mold compared to KT 204LC, it does not have levels of resistance comparable to NC 2000 or NC 2002. The level of tolerance in KT 206LC is similar to TN 90; under a low to moderate incidence of blue mold, damage is generally confined to the lower leaves and does not significantly decrease yields, but significant losses may occur when prevailing weather patterns lead to extreme blue mold pressure. A two year study demonstrated that significant differences exist among 15 commercial burley tobacco varieties that were evaluated for total tobacco specific nitrosamines (TSNA). Over eight trials, KT 204LC consistently produced lower levels of TSNA than did other varieties evaluated. Other varieties having relatively low levels of TSNA included TN 90LC and R 630LC. Varieties ms KY 14 X L8LC, NC BH129, and NC 6 produced relatively high levels of TSNA in each of the eight trials.

Impacts
The KTII research effort is totally funded by industry grants and contracts. Grants obtained during 2005-2007 totaled more than $2,594,000; since KTTII was initiated in 1999 total external funding is $5,547,000. The KTTII tobacco breeding program has a tremendous impact on the farm economy in Kentucky and Tennessee. For the 2007 growing season, KT 204LC, TN 90LC, TN 97LC, KT 200LC, and TN 86LC ranked first, second, fourth, fifth and sixth in terms of seed sales, accounting for over 75% of the total burley tobacco acreage in the United States; KT 204LC alone comprised over 40% of the 2007 US crop. US farmer sales of tobacco produced from KTTII cultivars should surpass $200 million for the 2007 growing season. These cultivars are also planted widely throughout other burley producing countries. TN 90LC has been chosen as the standard cultivar to be used in all CORESTA sponsored international tobacco research. Approximately 20% of the 2007 dark tobacco production in the United States was also produced from KTTII varieties KT D4LC, KT D6LC and TN D950LC.

Publications

  • No publications reported this period


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

Outputs
A new dark fire-cured tobacco cultivar, KT D6LC, was released by the Kentucky-Tennessee Tobacco Improvement Initiative (KTTII) breeding program in 2006. KT D6LC was compared with other dark commercial fire-cured cultivars in 12 trials conducted at Murray and Princeton, KY, and Springfield, TN in 2003 and 2004. In comparison to the other varieties, KT D6LC produced yields equal to KT D4LC; yield and revenue per acre of KT D6LC and KT D4LC were significantly higher than the other varieties each year. Although the black shank resistance of KT D6LC is similar to KT D4LC, it has higher resistance to black shank than other commercial dark tobacco varieties. In comparison to KT D4LC, the primary advantage of KT D6LC is improved quality and resistance to black root rot, tobacco mosaic virus, and wildfire. NL MadoleLC, KY 171LC, TN D950LC, and ms TN D950LC, low nicotine to nornicotine versions of previously released dark tobacco cultivars, were also released in 2006. The nornicotine content of these cultivars has been significantly reduced as a result of removing nicotine to nornicotine converter plants from foundation seed lots. Significant progress in the development of a burley tobacco cultivar having resistance to blue mold, black shank, and other major tobacco diseases was achieved in 2006. Several breeding lines having excellent blue mold and black shank resistance have been identified. Hybrid combinations of these lines were field tested in 2004-2006 and performed very well; black shank resistance and yield are comparable to KT 204LC, but the hybrids also have moderate resistance to blue mold. Three of these hybrids have passed minimum standards established by the Burley Regional Quality Trials and have been approved by that committee for release as commercial cultivars. It is anticipated that one of the hybrids will be officially released in time for commercial seed production in 2007, with release of a second hybrid anticipated in 2008 or 2009.

Impacts
The KTTII tobacco breeding program has a tremendous impact on the farm economy in Kentucky and Tennessee. For the 2006 growing season, KT 204LC, TN 90LC, TN 97LC, KT 200LC, and TN 86LC ranked first, second, fourth, fifth and sixth in terms of seed sales, accounting for over 70% of the total burley tobacco acreage in the United States. US farmer sales of tobacco produced from KTTII cultivars should surpass $240 million for the 2006 growing season. These cultivars are also planted widely throughout other burley producing countries. TN 90LC has been chosen as the standard cultivar to be used in all CORESTA sponsored international tobacco research and, according to international tobacco agronomists, is currently the most widely produced burley tobacco cultivar in the world. Approximately 25% of the 2006 dark tobacco production in the United States was also produced from KTTII varieties KT D4LC and TN D950LC.

Publications

  • Miller, R.D. 2006. Current status of black shank resistance in burley tobacco. Invited paper presented at the 42nd Tobacco Workers Conference, Charleston, SC. Tobacco Abstracts.
  • Miller, R.D.; Jack, A.; Bush, L.P. 2006. Reduction of tobacco specific nitrosamine (TSNA) levels in burley varieties having low nicotine to nornicotine conversion. Paper presented at the 42nd Tobacco Workers Conference, Charleston, SC. Tobacco Abstracts.
  • Kennedy, B.S.; Miller, R.D. 2006. Comparison of black shank disease resistance among tobacco cultivars containing monogenic and polygenic forms of resistance. Invited paper presented at the 42nd Tobacco Workers Conference, Charleston, SC. Tobacco Abstracts.
  • Jack, Anne; Bush, Lowell; Miller, Robert. 2006. The LC seed screening protocol. Paper presented at the 42nd Tobacco Workers Conference, Charleston, SC. Tobacco Abstracts.
  • Peek, Danny; Johnson, Chuck; Miller, R.D.; Blevins, Phil; and Kennedy, B.S. 2006. Evaluation of burley tobacco breeding lines for blue mold resistance and yield potential. Paper presented at the 42nd Tobacco Workers Conference, Charleston, SC. Tobacco Abstracts.


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

Outputs
A new dark fire cured tobacco cultivar, KT D4LC, was released by the Kentucky Tennessee Tobacco Improvement Initiative (KTTII) breeding program. KT D4LC was compared with dark fire-cured check varieties in 12 trials conducted at Murray and Princeton, KY, and Springfield, TN in 2001 through 2003. In comparison to the check varieties, KT D4LC produced the highest yield and revenue per acre each year. The grade index, which is a measure of quality based on USDA official grades, of KT D4LC was generally lower than that of NL Madole but equal to or higher than the grade index of other check varieties. KT D4LC was also compared with 15 commercial varieties in the Kentucky Tennessee dark fire-cured variety trials in 2002 and 2003. It ranked first for yield and revenue per acre in the trials both years; it was significantly higher yielding than all other varieties in 2003. Black shank resistance data collected from race 0 and race 1 nurseries indicate that KT D4LC has higher black shank resistance than other dark fire-cured varieties. In an on-farm black shank trial conducted in 2003, KT D4LC had substantially higher plant survival and yield in comparison to the check varieties. A study was conducted in 2004 to evaluate advanced burley breeding lines for resistance to blue mold and black shank. Results indicated that KTH 2404, 2405, and 2406 had medium resistance to blue mold and medium high resistance to race 0 and race 1 black shank. These three lines are also being evaluated for industry acceptability in the Regional Quality Test. If they meet the minimum standards defined by that program, one of the lines will be released as a commercial burley cultivar. A study was conducted in 2004 at four locations in Kentucky and Tennessee to determine the levels of secondary alkaloids and TSNA in air cured samples of 15 burley cultivars; the study included LC and non LC cultivars. Three replications were grown at each of the four locations, with data analyzed as a split plot design with locations as whole plots and cultivars as subplots. Highly significant differences were detected among locations and among cultivars for nicotine to nornicotine conversion and nitroso-nornicotine (NNN) and total TSNA levels. A highly significant correlation was found for percent conversion and NNN (r=0.75, Pr>r = 0.001) and for percent conversion and TSNA (r=0.58, Pr>r = 0.02). Across locations, percent conversion among cultivars ranged from 3.63 percent for KTH 2201LC to 9.62 percent for NC 6. NNN content ranged from 0.64ppm for KT 204LC to 6.19ppm for NC 6, while TSNA content ranged from 1.63ppm for KT 204LC to 10.02ppm for NC 6. Differences between LC and non-LC cultivars for TSNA content were particularly pronounced at the Versailles, KY location which had significantly higher levels of TSNA formation. At Versailles, NNN content ranged from 1.40ppm for KT 204LC to 19.33ppm for NC 6, while TSNA content ranged from 3.36ppm for KT 204LC to 31.34ppm for NC 6.

Impacts
The Kentucky Tennessee Tobacco Improvement Initiative (KTTII) breeding program has a tremendous impact on the farm economy in Tennessee and Kentucky. Five of the top six burley varieties produced in the United States (TN 90LC, KT 204LC, TN 86LC, TN 97LC and KT 200LC) were developed by the University of Tennessee or the Kentucky-Tennessee Tobacco Improvement Initiative. Among publicly released varieties, these five releases accounted for over 82% of total US burley tobacco acreage; when both public and private varieties are considered, KTTII releases account for approximately 65 percent of the US burley crop. Retail value for 2005 seed sales of these five varieties exceeded $1,500,000; based on average yields and prices for burley tobacco, sale of crops produced from these varieties will exceed $200 million for the 2005 crop year. KT 204LC has resistance to eight major tobacco diseases; it is the first burley cultivar with resistance to both race 0 and race 1 black shank that also has yield potential comparable to non-resistant varieties. According to international tobacco agronomists, TN 90 is currently the most widely produced burley tobacco variety in the world. TN 90 is also the standard burley variety used in all international collaborative studies conducted by the Cooperation Center for Scientific Research Relative to Tobacco (CORESTA). Approximately 25 percent of the dark tobacco production in the United States is also produced from varieties KT D4LC and TN D950 which were released by KTTII.

Publications

  • Miller, R.D., A.M. Jack, and L.P. Bush. 2005. The effect of reduced nicotine conversion on TSNA content in burley tobacco. Paper presented at the 2005 CORESTA Conference, Santo Cruz do Sul, Brazil. 2005 CORESTA Congress Program and Abstracts.
  • Miller, R.D., A.M. Jack, and L.P. Bush. 2004. Screening commercial burley tobacco cultivars for nicotine to nornicotine conversion. Paper presented at the Plenary Session of the 2004 CORESTA Conference, Kyoto, Japan. 2004 CORESTA Congress Program and Abstracts.


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

Outputs
Six new cultivars were released from the Kentucky-Tennessee Tobacco Improvement Initiative (KTTII) during 2004. Five of the new releases are the result of industry requests for cultivars with reduced formation of tobacco specific nitrosamines (TSNAs), which are known carcinogens. Research has demonstrated that there is a significant correlation between secondary alkaloid content and TSNA levels in tobacco. Nornicotine, the primary secondary alkaloid, occurs in some tobacco plants as a result of the spontaneous demethylation of nicotine; this process is commonly referred to as nicotine conversion. Levels of nornicotine present in a burley cultivar can be reduced by 70 to 80% by eliminating individual converter plants from foundation seed lots. This is accomplished by chemically analyzing seed plants as they are growing in the field and destroying all plants that have greater than 3% nornicotine. This process results in the production low converter (LC) cultivars. The LC cultivars will not differ from the original versions for yield, quality, agronomic type or disease resistance; only the chemistry has been altered. TN 90LC, TN 86LC, TN 97LC, KT 200LC, and KY 907LC were released by KTTII in 2004. KT 204LC, a new black shank resistant cultivar, was also released in 2004. The new cultivar has a higher level of black shank resistance than any cultivar currently available, and it is the first black shank resistant cultivar with yield potential comparable to the best non-resistant cultivars when grown under disease-free conditions. It has high resistance to black root rot, wildfire, and tobacco mosaic and tobacco vein mottling viruses. KT 204LC also has medium resistance to tobacco etch virus and low resistance to fusarium wilt; it is not resistant to blue mold. KT 204LC was compared with four standard burley cultivars in 17 non-black shank trials from 2000 through 2003. KT 204LC produced an average yield of 3739 kg/ha, compared with 3786 for Hybrid 403, 3564 for KT 200, 3436 for TN 97, and 3370 for TN 90. KT 204LC was the highest yielding cultivar among 30 entries in the 2003 commercial burley cultivar test conducted at Greeneville and Springfield, Tennessee, and Lexington and Versailles, Kentucky. The average yield of KT 204LC was 3859 kg/ha, compared with 3809 for Hybrid 403, 3585 for KT 200, 3495 for ms KY 14 X L8, and 3457 for TN 90. KT 204LC has consistently performed better than standard black shank resistant cultivars when evaluated under extreme disease pressure. In eight black shank trials conducted over two years, KT 204LC yielded an average of 2059 kg/ha, compared to 1475 for KT 200 and 1335 for TN 90. KT 204LC is a medium to late maturing cultivar, flowering approximately four days later than TN 90. It produces medium to tall plants with an average of 22 large leaves. The growth habit of KT 204LC is semi-upright, similar to TN 90. Cured leaf is medium to heavy bodied and tan to reddish-tan in color under normal curing conditions. KT 204LC has significantly better cured leaf color than KT 200 and is comparable to other popular burley cultivars.

Impacts
The Kentucky-Tennessee Tobacco Improvement Initiative tobacco breeding program has a tremendous impact on the farm economy in Kentucky and Tennessee. Among more than 35 commercial burley tobacco cultivars,TN 90, TN 86, TN 97 and KT 200 ranked first, third, fourth, and fifth in terms of seed sales in 2003, accounting for over 55 % of total burley tobacco acreage in the United States. Retail value for seed sales of these four varieties exceeded $3,000,000; based on average yields and prices for burley tobacco, sale of crops produced in Kentucky and Tennessee from these four varieties will exceed $600 million for this crop year. According to international tobacco agronomists, TN 90, which comprises 35-40% of the US crop, is currently the most widely produced burley tobacco variety in the world.

Publications

  • Miller, R.D., Jack, A.M., and Bush, L.P. 2004. Screening commercial burley tobacco cultivars for nicotine to nornicotine conversion. Paper presented at the Plenary Session of the 2004 CORESTA Conference, Kyoto, Japan. 2004 CORESTA Congress Program and Abstracts.


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

Outputs
The Universities of Kentucky and Tennessee merged their tobacco breeding programs in 1999 to form The Kentucky-Tennessee Tobacco Improvement Initiative. The primary objective of the combined program is the release of burley tobacco varieties having improved resistance to blue mold and black shank. In 2003, thirty advanced breeding lines and hybrids were evaluated for blue mold resistance in field nurseries located in Mexico and Guatemala. Seed was collected from plants showing high levels of resistance to blue mold. In subsequent plantings in black shank nurseries in Kentucky and Tennessee, several selections were identified that also had good resistance to race 0 and race 1 black shank. These selections are being screened in greenhouses for resistance to black root rot, wildfire, and TVMV, TEV, and TMV viruses. They are also being used to develop molecular marker techniques for screening for blue mold resistance in a laboratory. Six experimental hybrid cultivars were evaluated in black shank field trials conducted in Tennessee and Kentucky. These hybrids have total immunity to race 0 and high resistance to race 1 black shank; all of the experimental entries were much more resistant to black shank than resistant control varieties TN 90 and KT 200. Three of the entries are being evaluated in the 2003 Regional Quality Trials; if they pass minimum standards established in those trials one or more will be released in 2004 as a commercial burley tobacco hybrid cultivar.

Impacts
The Kentucky-Tennessee Tobacco Improvement Initiative tobacco breeding program has a tremendous impact on the farm economy in Kentucky and Tennessee. Among more than 35 commercial burley tobacco cultivars,TN 90, TN 86, TN 97 and KT 200 ranked first, third, fourth, and fifth in terms of seed sales in 2003, accounting for over 55 % of total burley tobacco acreage in the United States. Retail value for seed sales of these four varieties exceeded $3,000,000; based on average yields and prices for burley tobacco, sale of crops produced in Kentucky and Tennessee from these four varieties will exceed $600 million for this crop year. According to international tobacco agronomists, TN 90, which comprises 35-40% of the US crop, is currently the most widely produced burley tobacco variety in the world.

Publications

  • Ellis, R.L.; Miller, R.D.; Buchanan, J.R. 2002. Trickle Irrigation of Burley and Dark Fire-Cured Tobacco. Proceedings of the 40th Tobacco Workers Conference, Pinehurst, NC.
  • Hensley, R.A.; Miller, R.D.; Ritchie, E.L.; Ellis, R.L.; Calvert, J.R. 2002. Effects of Cover Type and Dibble Depth on the Production of Tobacco Plants in Outdoor Float Beds. Proceedings of the 40th Tobacco Workers Conference, Pinehurst, NC.
  • Hill, R.A.; Miller, R.D.; Ellis, R.L.; Lax, T.W. 2002. The Effect of Nitrogen Rate and Foliar Fertilization on Dark Fire-Cured Tobacco. Proceedings of the 40th Tobacco Workers Conference, Pinehurst, NC.
  • Kennedy, B.S.; Miller, R.D. 2002. Field Inoculation Techniques for Evaluation of Fusarium Wilt Resistance among Burley Tobacco Varieties. Proceedings of the 40th Tobacco Workers Conference, Pinehurst, NC.
  • Knott, C.A.; Miller, R.D.; Nesmith, W.C. 2002. Resistance of Six Tobacco Cultivars to Blue Mold at Varying Stages of Vegetative Growth. Proceedings of the 40th Tobacco Workers Conference, Pinehurst, NC.
  • Ritchey, E.L.; Miller, R.D.; Ellis, R.L. 2002. The Effect of Nitrogen Rate and Foliar Fertilization on Yield and Nitrosamine Levels in Burley Tobacco. Proceedings of the 40th Tobacco Workers Conference, Pinehurst, NC.