46th TWC, Tob. Work. Conf., 2014, abstr. 11

Effect of maturity and field wilting method on TSNA in dark fire-cured tobacco

University of Kentucky, Research & Education Center, 1205 Hopkinsville Street, Princeton, KY 42445, USA

Field experiments were conducted at the University of Kentucky Research & Education Center near Princeton KY in 2013 to evaluate the effect of crop maturity and use of burlap during field wilting on TSNA in dark fire-cured tobacco. Trials included Narrowleaf (NL) Madole LC (low converter) and TR Madole HC (high converter). All tobacco was transplanted June 4, 2013 and managed under standard production practices. 100 sticks (50 sticks NL Madole and 50 sticks TR Madole) were harvested at either 4.5 weeks or 9 weeks after topping and fire-cured for 5 weeks. Although barn temperatures were hotter during the early cure, due in large part to much cooler outside temperatures during the late cure, TSNA were higher in the early cure of NL Madole LC (4.83 ppm in early cure vs. 3.56 ppm in late cure). Time of harvest/maturity did not have a significant effect on TSNA in TR Madole HC, although numerical TSNA levels were also slightly higher in the early cure. In a separate experiment at late harvest, NL Madole LC and TR Madole HC were harvested, spiked on sticks, and stacked in piles of 5 sticks each and either covered with burlap for 48 hours or left uncovered to field wilt. Meters were placed within the middle of each covered and uncovered pile to measure temperature and relative humidity every hour within each pile during field wilting. Meters were then removed as tobacco was picked up, housed, and fire-cured similarly to previous experiments. Piles covered with burlap had maximum and average temperatures that were approximately 3 F and 1 F cooler, respectively, than uncovered piles. Use of burlap covering during field wilting did not affect fire-cured TSNA in either variety. (Reprinted with permission)