Progress 07/01/08 to 06/30/13
Outputs
Target Audience: Tobacco producers, extension personnel, and industry representatives Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Research personnel attended the Tobacco Workers' Conference, Tobacco Science Research Conference, and CORESTA. Three graduate students are currently training in the research program. How have the results been disseminated to communities of interest? Varieties have been released through participating seed companies. Research findings have been disseminated through grower meetings and research conferences. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
New burley varieties KT 209LC, KT 210LC, and KT 212LC and dark tobacco variety KT D8LC were developed and released for production by tobacco growers
Publications
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: The primary objective of the Kentucky-Tennessee Tobacco Improvement Initiative (KTTII) breeding program is the development of burley and dark tobacco cultivars having improved disease resistance. KT 212LC was released in March of 2012 to provide burley producers with an early maturing variety that also possesses moderate resistance to race 1 black shank. The new variety has a yield rating of eight and disease resistance ratings of: 10 for race 0 black shank; 4 for race 1 black shank; 5 for fusarium wilt; and high for black root rot, wildfire, and tobacco mosaic virus. It is susceptible to TVMV, TEV, PVY, and blue mold. The maturity of KT 212LC is very similar to ms KY 14 X L8LC, but much earlier than previous KT varieties. The growth habit of KT 212LC is not as erect as previous KT varieties, but it is not as droopy as ms KY 14 X L8LC. KT 212LC was compared with six standard burley varieties in twelve advanced breeding line trials from 2009 through 2011. In the absence of black shank, the yield of KT 212LC was higher than the yield for TN 90LC, comparable with ms KY 14 X L8, but somewhat lower than for KT 204LC, KT 206LC, KT 209LC, and KT 210LC. KT 212LC was comparable with the check varieties for the quality index, which is indicative of cured leaf quality as judged by official USDA grades, and gross income per acre. When evaluated for percent survival in black shank nurseries, the performance of KT 212LC was similar to TN 90LC, much better than ms KY 14 X L8LC, but substantially worse than the other KT varieties. It is not recommended for use in fields having a history of black shank. KT 212LC will be available to growers for the 2013 production season. Two other KTTII breeding lines are nearing release as commercial cultivars. DFH 1101 is a dark tobacco hybrid breeding line that has excellent yield potential and significantly higher resistance to race 1 black shank in comparison to existing dark cultivars. It has received a good quality rating in performance trials and is currently being evaluated for industry usability and chemical characteristics. If it is found to meet industry standards, it will be released in early 2014. KTH 2802 is a high yielding burley hybrid breeding line that has superior combined resistance to race 1 black shank and fusarium wilt than existing burley cultivars. In performance trials conducted in disease nurseries, KTH 2802 has displayed higher resistance to fusarium wilt than the resistant standard KT 210LC, and higher resistance to race 1 black shank than KT 209LC, which is currently the most resistant commercial cultivar available to growers. KTH 2802 was entered in the 2012 Regional Quality Test; if it meets the minimum standards established for that program it will be released as KT 213LC in February, 2013. Another major objective of KTTII is the introgression of e4/e5/e10 mutant alleles into existing KTTII burley cultivars to minimize the conversion of nicotine to nornicotine, a crucial step in the formation of TSNA. This project is nearing completion and it is anticipated that several breeding lines containing the mutant alleles will be entered into the 2013 RQT program. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The objectives of the Kentucky-Tennessee Tobacco Improvement Initiative (KTTII) are to develop improved tobacco varieties, support tobacco genetics research, and more efficiently deliver new technologies for the maximum benefit of burley and dark tobacco farmers in Kentucky and Tennessee. Considerable progress has been made in the area of variety development. Six new burley varieties (KT 200, KT 204LC, KT 206LC, KT 209LC, KT 210LC and KT 212LC) have been released since the year 2002. In addition, older varieties TN 86, TN 90, TN 97, KY14, KY17, KY 907, and ms KY 14 X L8 have been re-released as new low nicotine converting (designated as LC) varieties due to new, more stringent chemical standards throughout the tobacco industry. Dark tobacco varieties developed by KTTII include KT D4LC, KT D6LC, and KT D8LC. In keeping with the mission of Land Grant Universities, varieties developed by KTTII are made available to all burley and dark tobacco growers through non-exclusive releases to participating tobacco seed companies. These new varieties have been readily accepted by tobacco growers. The top five burley varieties grown each year from 2008 through 2012 were released by KTTII, comprising approximately 75-80% of the US crop. The release of the new varieties has increased profitability of burley tobacco growers. Tobacco extension specialists in Kentucky and Tennessee estimate that the average yield increase due to these KTTII varieties is approximately 200-300 lbs per acre; for growers with black shank, yield increases would be much higher. USDA estimates indicate that 96,800 acres were planted in burley tobacco in the US during the 2012 crop year; based on seed sales records, at least 75% or 72,600 acres were planted in KTTII varieties. At an average price of $1.75 per pound, an increased yield of 200 lbs/acre due to the use of KTTII would result in over $25,000,000 in increased income for US burley tobacco growers in 2012 alone. The emphasis of the KTTII breeding program includes 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. Prior to 2008, the focus of KTTII was the development of new disease resistant tobacco varieties. However, one of the primary emphases of KTTII now is breeding for improved chemical characteristics that will lead to less harmful tobacco products. With the passage of The Family Smoking Prevention and Tobacco Control Act in 2009, the U.S. Food and Drug Administration (FDA) now has regulatory oversight of tobacco products in the United States. This development, coupled with the World Health Organization (WHO) Framework Convention on Tobacco Control, makes it highly likely that the importance of breeding for altered chemical composition will increase in the future. The development of these reduced harm varieties, coupled with other on-going KTTII research, is imperative if burley and dark tobacco grown in the US is to remain competitive on the world export market.
Publications
- Li, Dandan, Ramsey S. Lewis, Anne M. Jack, Ralph E. Dewey, Steve W. Bowen and Robert D. Miller. 2011. Development of CAPS and dCAPS markers for CYP82E4, CYP82E5v2 and CYP82e10 gene mutants reducing nicotine to nornicotine conversion in tobacco. Molecular Breeding. Online, April 11, 2011. (doi:10.1007/s11032-011-9575-9). Miller, R.D., L.P. Bush, and A.M. Jack. 2012. Effects of variety and harvest management on cured leaf quality and TSNA content of burley tobacco. Paper presented at the 66th Tobacco Science Research Conference, Concord, NC. Proceedings. In Press.
- Miller, R.D., B.R. Neal, B.R., G.A. Weinberger, and R.A. Hensley. 2012. Effects of variety and harvest management on burley tobacco quality. Paper presented at the 45th Tobacco Workers Conference, Williamsburg, VA. Proceedings.
- Li, D., A. Jack, and R. Miller. 2012. Selection for the low alkaloid trait: Part 2 - marker assisted selection. Paper presented at the 45th Tobacco Workers Conference, Williamsburg, VA. Proceedings.
- Miller, R.D., L.P. Bush, and A.M. Jack. 2012. Effects of variety and harvest management on cured leaf quality and TSNA content of burley tobacco. Paper presented at the 2012 CORESTA Conference, Sapporo, Japan. Proceedings. In Press.
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: The objective of the Kentucky-Tennessee Tobacco Improvement Initiative (KTTII) breeding program is the development of burley and dark tobacco cultivars having improved disease resistance and acceptable chemical characteristics, with special emphasis on reduced nornicotine and tobacco specific nitrosamine (TSNA) content. Nornicotine is a precursor of an important tobacco-specific nitrosamine, N'-nitrosonornicotine (NNN), which is reported to be a carcinogenic component of tobacco products. Nornicotine is derived predominantly from nicotine by nicotine demethylase enzymes. Three genes (CYP82E4, CYP82E5v2, and CYP82E10) with different sites and levels of activity that encode for these enzymes have been identified by researchers at North Carolina State University; ethane methyl sulfonate has since been used to introduce mutations into each of these genes to prevent production of functional gene products. An immediate objective of KTTII is the introgression of e4/e5/e10 mutant alleles into existing KTTII burley cultivars to minimize the conversion of nicotine to nornicotine. Our research program has developed efficient DNA markers that can be used to differentiate between wild type and mutant alleles. Four dCAPS (derived cleaved amplified polymorphic sequence) markers were designed for a truncation mutation in CYP82E4, and one for a similar mutation in CYP82E5v2. Two CAPS (cleaved amplified polymorphic sequence) markers were designed for a deleterious mutation in CYP82E10. Because of the co-dominant nature of the CAPS and dCAPS markers, heterozygous and homozygous plants can be differentiated. Genotypes determined by the CAPS and dCAPS marker methods were validated by DNA sequencing and phenotyping plants carrying various mutant combinations. These markers can be used in marker-assisted selection programs to quickly introgress the desired mutations into commercial varieties to impact nornicotine and NNN levels in tobacco leaves and derived products. At present we, have BC3 or BC4 versions of several commercial varieties that hare homozygous for the desired e4/e5 alleles; research is currently underway to also introduce the e10 alleles into these lines. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The emphasis of the KTTII breeding program includes 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. Prior to 2008, the focus of KTTII was the development of new disease resistant tobacco varieties. However, the primary emphasis of KTTII now is breeding for improved chemical characteristics that will lead to less harmful tobacco products. With the passage of The Family Smoking Prevention and Tobacco Control Act in 2009, the U.S. Food and Drug Administration (FDA) now has regulatory oversight of tobacco products in the United States. This development, coupled with the World Health Organization (WHO) Framework Convention on Tobacco Control, makes it highly likely that the importance of breeding for altered chemical composition will increase in the future. The incorporation of the e4/e5/e10 alleles into commercial burley varieties will greatly reduce levels of NNN, which is a known carcinogen. Although this project is on-going, it is anticipated that new varieties with much reduced TSNA content will be available for commercial production within the next three to four years. The development of these reduced harm varieties, coupled with other on-going KTTII research, is imperative if burley tobacco grown in the US is to remain competitive on the world export market. Although much of the research focus of KTTII has shifted to reduced harm varieties, the development of varieties with improved disease resistance continues to be a major objective. Black shank, a soil-borne fungal disease, is particularly devastating, leading to the loss of millions of dollars to growers each year. While approximately 75% of US burley production is comprised of black shank resistant varieties developed by KTTII, there are currently no early maturing black shank resistant varieties. The release of KT 212 will give growers who have black shank infested soils the ability to spread their crops over a longer growing season to better manage labor, equipment and barns. With the passage of the Fair and Equitable Tobacco Reform Act of 2004, there has been a shift in the number and size of burley tobacco farms in Kentucky and Tennessee. Fewer growers with much larger acreages are no longer able to harvest tobacco only under optimal conditions; many begin harvest in late July and continue until the first frost, regardless of impending rainfall. The 2011 study to determine the relative impact of variety and management practices on quality of burley tobacco demonstrated that although there was no significant difference among varieties for cured leaf quality, rainfall occurring while tobacco remained in the field dramatically reduced leaf quality. Tobacco harvested in late September was more likely to cure with a variegated color than tobacco harvested in mid-August. This information will be presented to growers at Extension meetings and University field days to help grower better manage harvest of their crops.
Publications
- Li, Dandan, Ramsey S. Lewis, Anne M. Jack, Ralph E. Dewey, Steve W. Bowen and Robert D. Miller. 2011. Development of CAPS and dCAPS markers for CYP82E4, CYP82E5v2 and CYP82e10 gene mutants reducing nicotine to nornicotine conversion in tobacco. Molecular Breeding. Online, April 11, 2011.
- Miller, R.D. 2011. Evaluation of burley cultivars for leaf quality. Paper presented at the 65th Tobacco Science Research Conference, Lexington, KY. Tobacco Abstracts, In Press.
- Martinez, N., R.D. Miller, and G. Weinberger. 2011. Selection of resistance to multiple pathogens in tobacco assisted by markers and greenhouse screenings. Paper presented at the 65th Tobacco Science Research Conference, Lexington, KY. Tobacco Abstracts, In Press.
- Li, D. A. Jack, and R.D. Miller. 2011. Marker assisted selection (MAS) for tobacco alkaloids. Paper presented at the 65th Tobacco Science Research Conference, Lexington, KY. Tobacco Abstracts, In Press.
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Nornicotine is a precursor of an important tobacco-specific nitrosamine, N'-nitrosonornicotine , which is reported to be a carcinogenic component of many tobacco products. Nornicotine is derived predominantly from nicotine through a demethylation process catalyzed by nicotine demethylase enzymes. Three genes (CYP82E4, CYP82E5v2, and CYP82E10) with different sites and levels of activity that encode for these enzymes have been identified by researchers at North Carolina State University; ethane methyl sulfonate has since been used to introduce mutations into each of these genes to prevent production of functional gene products. Our research program has developed efficient and user-friendly DNA markers for these mutations based on single nucleotide polymorphisms (SNPs) between wild type and mutant alleles. Four dCAPS (derived cleaved amplified polymorphic sequence) markers were designed for a truncation mutation in CYP82E4, and one for a similar mutation in CYP82E5v2. Two CAPS (cleaved amplified polymorphic sequence) markers were designed for a deleterious mutation in CYP82E10. Because of the co-dominant nature of the CAPS and dCAPS markers, heterozygous and homozygous plants can be differentiated. Genotypes determined by the CAPS and dCAPS marker methods were validated by DNA sequencing and phenotyping plants carrying various mutant combinations. These markers can be used in marker-assisted selection programs to quickly introgress the desired mutations into commercial varieties to impact nornicotine and NNN levels in tobacco leaves and derived products. Floral induction was achieved in tobacco plants by transferring 25 day old seedlings into styrofoam trays, which were subsequently placed on water containing high rates of Terramaster, a fungicide labeled for use in tobacco transplant production. The seedlings remain on the Terramaster until the first indication of flowering, which typically occurs 60 days after seeding or 35 days after the Terramaster treatment begins. The plants are then transferred to pots, with seed collection possible 30-35 days later. This shortened flowering cycle greatly reduces the time required for many plant breeding procedures. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The University of Kentucky and the University of Tennessee merged their tobacco breeding programs 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 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 2009 - 2010 totaled $2,224,232; since KTTII was initiated in 1999 total external funding is $7,560,232. The primary objective of the KTTII breeding program is the development of burley and dark tobacco cultivars having improved disease resistance and acceptable chemical characteristics, with special emphasis on reduced nornicotine and tobacco specific nitrosamine (TSNA) content. Since its inception in 1999, KTTII has released burley varieties KT 200LC, KT 204LC, KT 206LC, KT 209LC, and KT 210LC; dark varieties include KT D4LC, KT D6LC, and KT D8LC. These new releases have been readily accepted by tobacco growers in Kentucky and Tennessee. Based on seed sales records, it is estimated that KTTII varieties comprised approximately 75-80% of the US burley crop each of the last four years. 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.
Publications
- Li, Dandan, R.S. Lewis, A.M. Jack, R.E. Dewey, S.W. Bowen and R.D. Miller. 2011. Development of CAPS and dCAPS markers for CYP82E4, CYP82E5v2 and CYP82e10 gene mutants reducing nicotine to nornicotine conversion in tobacco. Molecular Breeding. In Press.
- Miller, R.D. and R.A. Hensley. 2010. Chemical induction of premature flowering in tobaccco. Paper presented at the 2010 CORESTA Conference, Edinburgh, Scotland. 2010 CORESTA Congress Program and Abstracts.
- Li, D., P. De Sa, and R.D. Miller. 2010. Development of SCAR marker linked to black shank resistance gene in tobacco. Paper presented at the 44th Tobacco Workers Conference, Lexington, KY. Tobacco Abstracts.
- Li, D., R. Lewis, A. Jack, R. Dewey, S. Bowen, and R. Miller. 2010. Development of dCAPS markers for CYP82E4 and CYP82E5 gene mutations in tobacco. Paper presented at the 44th Tobacco Workers Conference, Lexington, KY. Tobacco Abstracts.
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Two new burley tobacco cultivars, KT 209LC and KT 210LC, were released by the Kentucky-Tennessee Tobacco Improvement Initiative (KTTII) in March, 2009. KT 209LC has superior black shank resistance 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 210LC has good black shank resistance and moderate fusarium wilt resistance. It also has high resistance to black root rot, wildfire, and tobacco mosaic virus, but it is susceptible to tobacco vein mottling virus and tobacco etch virus. Fusarium wilt is a soil-borne fungal disease that is present in some tobacco producing regions of Kentucky, primarily along the Ohio River; it is relatively rare in Tennessee. Because several older varieties developed at the University of Kentucky had good fusarium wilt resistance, the disease was not a significant problem for many years. However, newer varieties that have high levels of resistance to race 1 black shank and tobacco etch and tobacco vein mottling viruses do not have fusarium wilt resistance. As these newer varieties began to comprise most of the United States burley crop, fusarium wilt reappeared in some areas. The problem is particularly severe for growers who have both fusarium wilt and race 1 black shank present in their soils. KT 210LC is the first burley variety having moderate to high race 1 black shank resistance and moderate fusarium wilt resistance. Like KT 204LC and KT 206LC, KT 209LC and KT 210LC are late maturing varieties; all four lines have essentially the same flowering date. KT 209LC and KT 210LC flower approximately 7-8 days later than KY 14 and 4-5 days later than VA 509. KT 209LC and KT 210LC have similar plant height, leaf number, and leaf width; KT 210LC has a slightly longer leaf than does KT 209LC. The growth habit of both KT 209LC and KT 210LC is upright and is very similar to KT 204LC and KT 206LC. Although the quality index of the two lines was essentially the same in the 2008 Regional Quality Trial, KT 210LC had a slightly higher industry usability rating. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The KTTII breeding program was established to develop improved tobacco cultivars and germplasm, conduct applied research to help growers select and integrate appropriate crop cultivars into specific farm production practices, and provide unbiased information on performance and quality of crop cultivars to producers and associated industries. The primary objective of the KTTII breeding program is the development of burley and dark tobacco cultivars having improved disease resistance and acceptable chemical characteristics, with special emphasis on reduced nornicotine and tobacco specific nitrosamine (TSNA) content. Diseases of particular interest are black shank and blue mold. Since its inception in 1999, KTTII has released burley varieties KT 200LC, KT 204LC, KT 206LC, KT 209LC, and KT 210LC; dark variety releases include KT D4LC, KT D6LC, and KT D8LC. Older varieties TN 86, TN 90, TN 97, KY 14, KY 17, KY 907, ms KY 14 X L8, KY 171, NL Madole, and TN D950 have also been re-released as new low nicotine converting (designated as LC) varieties due to new, more stringent chemical standards throughout the tobacco industry. The KTTII tobacco breeding program has a tremendous impact on the farm economy in Kentucky and Tennessee. KTTII cultivars were estimated to comprise 70-80% of burley production and 20-25% of dark tobacco production in the United States in 2008 and 2009. The KTTII program is heavily funded by industry grants and contracts, with total external funding to date exceeding $7,051,000.
Publications
- No publications reported this period
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: A program to utilize marker assisted selection to enhance the development of new tobacco cultivars by the Kentucky-Tennessee Tobacco Improvement Initiative (KTTII) was begun in 2008. Marker assisted selection has the potential to eliminate many of the problems associated with traditional breeding techniques because it is based on determining the genotype of individual plants via DNA analysis rather than on the phenotypic reaction of plants when challenged with specific disease pathogens. To date, KTTII has successfully utilized genetic markers to characterize breeding lines for the presence or absence of resistance genes for race 0 black shank, blue mold, black root rot, and potato virus Y. Genetic markers have also been identified for the two major genes that control total alkaloid content in tobacco. The ability to use genetic markers to select plants having low alkaloid content and/or blue mold resistance is particularly valuable due to the difficulty in identifying these genotypes under normal field conditions. A second major research objective that was initiated in 2008 is the incorporation of nornicotine knockout mutations into existing KTTII cultivars. These mutant lines were developed at NC State University. The first gene, CYP82E4, typically results in nornicotine levels equal to, or slightly lower than, the best existing low nicotine converting (LC) cultivars; however, unlike LC cultivars, the mutant gene is genetically stable and should eliminate the back-mutation to the allele causing nicotine to nornicotine conversion. The second mutant gene, CYP82E5v2, is believed to eliminate the residual levels of nornicotine that remains in LC cultivars; however this is yet to be totally confirmed. These genes will be incorporated into TN 90LC and the parental lines of KT 204LC and KT 206LC through conventional back-cross breeding procedures, with the presence or absence of the genes in segregating populations being verified via DNA sequencing in KTTII laboratories. 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 and the University of Kentucky tobacco breeding programs were merged in 1999 to form the Kentucky-Tennessee Tobacco Improvement Initiative (KTTII). To date, KTTII has developed and released eight burley and 7 dark tobacco varieties. The program 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. KTTII has a tremendous impact on the farm economy in Kentucky and Tennessee. KTTII cultivars are estimated to comprise over 80% of burley production and approximately 20% of dark tobacco production in the United States during 2008. KTTII cultivars are also planted widely throughout other tobacco producing countries.
Publications
- No publications reported this period
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