Some Effects of 2‐Chloroethyl‐phosphonic Acid (CEPA) on Burley Tobacco (Nicotiana tabacum L.) Cured Detached from the Stalk¹

Abstract

To make mechanical leaf harvesting of burley tobacco (Nicotiana tabacum L.) practical, the problem of physiological immaturity of leaves cured detached from the stalk must h,e solved. An ethylene releasing agent, 2‐chloroethyl‐phosphonic acid (CEPA), has been found to “ripen” plant leaves. The objective of this experiment was to determine if CEPA treatment before harvesting burley tobacco and curing it detached from the stalk alleviates the physiological immaturity of such tobacco. Ten cultivars and breeding lines were grown in a split‐split‐plot design with genotypes as whole plots, methods of curing as subplots, and CEPA vs no CEPA treatments as sub‐subplots. Two weeks after topping and 4 days before harvesting, CEPA at the rate of 150 Mg/ plant was applied according to the experimental design. After curing, yield and grade index were determined for each treatment. Samples were then drawn from the leaf web, ground, and analyzed for percent total nitrogen, percent α‐amino nitrogen, water‐soluble acids, pH, percent ash, percent K20, percent nicotine, and percent nornicotine. The method of curing significantly affected grade index, percent total nitrogen, percent a‐amino nitrogen, percent nicotine, and pH. CEPA treatment effects were statistically significant for percent total nitrogen, percent α‐amino nitrogen, and percent ash. The level of each of these constituents was significantly closer to that of stalkcured tobacco after leaves cured detached from the stalk had been treated with CEPA. CEPA‐treated Burley 37, Va 509, and 69‐517 cured detached had more tobacco graded usable by cigarette manufacturers than did tobacco with any other treatments. These results indicate that some important chemical constituents and physical characteristics are modified in a desirable direction by CEPA treatments. However, there may be detrimental effects, such as off‐flavor of the smoke, associated with CEPA treatments which would preclude using the chemical.