TSRC, Tob. Sci. Res. Conf., 2018, 72, abstr. 070 (also presented at CORESTA 2018)

Production of very low nicotine burley tobacco: short term feasibility from an agronomy viewpoint

University of Kentucky, Lexington, KY, USA

The FDA has issued an ANPRM to obtain information for developing a product standard that would lower nicotine to non-addictive levels, and requested comments on a limit of around 0.3-0.5 mg/g. We do not believe that this limit is technically feasible on a nationwide scale in the short term with the varieties currently available. Nicotine levels are extremely variable between crops. We examined data collected in the Minimum Standards Program. Nicotine levels were mostly 35 – 55 mg/g, but they ranged from 18 mg/g to 72 mg/g. These data are weighted means for the whole plant; the leaf grade, which comprises most of the weight, is at least 12-15% higher. LA (low alkaloid) mutants reduce nicotine to about 10% of the wild type: 3.5 – 5.5 mg/g in the average crop, which is still tenfold higher than the limit in question. Agronomic practices can reduce nicotine further, but results are notoriously variable. Data we have collected over the years show: a) not topping reduced nicotine to 55-60% of topped tobacco b) close spacing reduced it to 65-95% of standard spaced tobacco c) drastically reducing nitrogen fertilizer reduced it to 40-94% of standard fertilized tobacco d) early harvesting reduced it to 64-78% of standard harvested tobacco. We are currently testing the combined effect of all these factors. We do not yet have any data, but it is unlikely that it will reduce nicotine to below 10% of standard-grown tobacco, and even more unlikely that it will do so consistently. Several groups are working on molecular nicotine reduction. It is possible that they will achieve the 0.3-0.5 mg/g nicotine levels, but it could be years before such varieties are available to growers on a commercial scale, if the industry maintains its current testing procedures.