Grants and Contracts Details


Most of the work done to reduce TSNAs in cured burley tobacco leaf has targeted the conversion of nicotine to nornicotine. The introduction of seed screening to eliminate plants with a high potential to convert nicotine to nornicotine has resulted in low converter (LC) varieties. Another approach is to modify the current varieties to include the demethylase mutant genes. Another approach is to use of green tobaccos that have a much lower propensity for conversion of nicotine to nornicotine than in burley. This may be a direct result of the higher nitrogen rates that are required to produce an acceptable yield and quality of burley. This high level of N fertilization results in higher levels of alkaloids, and consequently a greater potential for nornicotine and NNN accumulation. Introducing a green gene into burley would further reduce the propensity of burley to produce NNN. This approach would also reduce production cost. Despite the differences in leaf chemistry between burley and flue-cured, most of these differences are the result of genetic diversity between varieties, and not the class of tobacco (burley or flue-cured) or the chlorophyll status of the plant. The manufactures' requirement for desirable burley characteristics is not necessarily linked to the chlorophyll either because Maryland (MD) tobacco is green but can be used as a burley substitute. The possibility of poor air-cured leaf quality of a green style of burley can be reduced by including the "pale yellow" gene in to green burley. This gene causes the plant to lose its chlorophyll very quickly after harvest. The opportunity, therefore, exists of developing a "dark" burley that has an increased level of chlorophyll and so requires less fertilizer, and also contains the pale yellow trait that will ensure that the green tobacco will still cure like a conventional burley, even in a less than optimum curing environment. Some preliminary work to develop a "pale yellow dark burley" has been done. An elite burley line that has resistance several important diseases in Kentucky has been crossed with a Maryland tobacco variety. The source of the pale yellow gene has also been crossed to the elite burley line. Both of these were screened for blackshank race 1 resistance in 2013. Marker selection breeding will used for traits for which this is possible, but screening in a field infected with blackshank race 1 will have to be done at each stage of the program.
Effective start/end date4/1/143/31/15


  • Council for Burley Tobacco: $10,000.00


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