Bull. Spec. CORESTA Congress, Lisbon, 2000, p. 97, A9
Lowering the nicotine content of flue-cured tobacco cultivars in South Africa
Tobacco and Cotton Research Institute, Soil and Crop Science Division, Rustenburg, South Africa
The nicotine content of flue-cured tobacco produced in the RSA is determined by factors suchas soil fertility, climatic conditions and production practices. The nicotine content of the leaf cannot be reduced dramatically without a detrimental effect on the physical and chemical properties of the leaf and without destroying the economic viability of the crop. High yields and good-quality leaf can be achieved by means of optimum fertilization practices but these practices also result in a high nicotine content of 2.8-3.3%. The effects of agronomic practices on nicotine content and marketable yield were evaluated for seven successive seasons, starting in 1992. Cultivars OD234, OD469, OD272, OD486 and OD1 were evaluated. Existing cultivars were tested in the North West, Northern and Mpumalanga Province on different soil types, namely sandy soils with 4% clay and clay loam soils with a 36% clay content. During the first two growing seasons, the effects of topping height and different nitrogen fertilization levels were evaluated. The highest marketable yield and lowest nicotine content of 2,6% were obtained at the highest topping height and lowest level of nitrogen fertilization. During the 1995 and 1996 season, the lowest marketable yield was obtained at a high nitrogen level and the lowest nicotine content of 2,3% at the lowest nitrogen level. During 1996, 1997 and 1998 the lowest nicotine content was obtained at the lowest nitrogen level, but the nicotine content increased as the nitrogen level increased. The highest marketable yield was also obtained at high nitrogen levels. This study indicates that some cultivars grown in South Africa tend to have a lower nicotine content than others. However, within limits, the nicotine content of the tobacco leaf can be lowered by changing the growing conditions and a new set of cultivation procedures will have to be evaluated.