Topping Height of High Leaf Potential Varieties

The Council for Burley Tobacco funded this project in 2015; we are applying for a second year of funding because we would like to repeat it in 2016 so that we have two years of data. The 2015 crop is currently curing, so we do not yet have any data. An interim report was submitted in October. The newer burley hybrids are considered "late-maturing" because they only produce flowers once they have a high number of leaves. If these hybrids are topped at the same stage of flowering as the earlier maturing varieties, they could have as many as six leaves more than the older varieties that are topped to 22 - 24 leaves. There are potentially several advantages of topping these high leaf number hybrids earlier, when leaves 22 - 24 are 6-8" long: curing during warmer weather, stripping costs reduced, shorter stalks are easier to handle after cutting, sucker control would be more effective, the crop will be less prone to lodging in high wind and there would be less insect pressure and need for insecticide. A major advantage would be the possibility of chemical topping that would further reduce labor costs. The newer burley hybrids have up to 30 leaves and are very tall. If these are topped according to the current Kentucky-Tennessee Production Guidelines, these plants are very difficult to handle and stripping costs are greater than the older, shorter varieties with fewer leaves. Sucker control would also be more effective, the crop will be less prone to lodging in high wind A major advantage would be the possibility of chemical topping that would further reduce labor costs.