Evaluation and Control of Ground Sucker Formation in Burley Tobacco Varieties

The use of hydroponically produced tobacco transplants, commonly referred to as “float plants”, has been widely adopted by tobacco producers over the last several years. There are many advantages to using float plants; however, one negative aspect of float plants is their increased propensity to form adventitious basal shoots, commonly referred to as “ground suckers”. Although the growth of ground suckers is often repressed following transplanting, they sometimes continue to grow and may reach a length of 4-5 feet. This may pose significant problems when the plants are ready to cut at harvest, and may significantly reduce yields of the primary plants.The hypothesis that the proposed research will investigate is that this difference in root to shoot ratio between traditional versus hydroponically produced transplants results in a significantly different auxin to cytokinin ratio, thereby affecting the development of ground suckers. In other words, the ratio between these two phytohormones in float plants versus traditional plants may approximate the differences observed in topped versus non-topped mature tobacco plants. The research will investigate tobacco varieties known to have a propensity to form ground suckers (e.g. TN 86) versus those where ground suckers are rarely observed (e.g. Hybrid 403). The initial research will be done in the laboratory utilizing tissue culture to determine the response of TN 86 and H 403 plantlets grown on media containing varying levels of auxins and cytokinins. Based on results of the tissue culture studies, a followup study will be conducted in the greenhouse to determine optimal levels of hormone concentrations in hydroponic solutions that could possibly minimize the formation of adventitious axillary buds without significantly altering stem elongation or plant growth. It is anticipated that these preliminary studies will provide a range of hormone concentrations that can be field tested to determine their effectiveness in minimizing or eliminating ground sucker formation without adversely affecting plant growth or yield potential.