A Comparative Assessment of Nicotine and Reducing Sugar Levels in Flue Cured Tobacco Varieties in the Small Scale Sector of Mutare District

Abstract

Tobacco is the most widely grown and cured non-food crop worldwide. Nicotine content and reducing sugar levels are properties that determine quality in tobacco leaves. The study aimed at determining nicotine and reducing sugar levels in leaves of varieties KRK 26R and T 76 at three leaf ripeness stages of unripe, ripe and overripe. Each variety was grown by three small scale growers and leaves harvested at the unripe, ripe and overripe stages were analysed for nicotine and reducing sugar levels. Nicotine and reducing sugar levels were determined at the Tobacco Research Board laboratory. The data was analysed using Minitab version13 statistical package. The means of nicotine content and reducing sugar levels were compared using the paired T tests for each stage of ripeness within each variety and between the two varieties. The means of nicotine content levels in variety KRK 26R were as follows; 2.633% unripe leaves, 3.87% ripe leaves and 4.477% overripe leaves. The reducing sugar levels in variety KRK 26 R were as follows; 13.39% on unripe leaves, 14.567% on ripe leaves and 7.57% on overripe leaves. The means of nicotine levels on variety T76 were as follows; 2.78% on unripe leaves, 3.223% ripe leaves and 4.273% overripe leaves. The reducing sugar levels in variety T 76 were as follows; 12.84% unripe leaves, 17.103% ripe leaves and 8.893% unripe leaves. There were significant differences (P<0.05) in the nicotine content in KRK 26 R between the unripe and ripe leaves, and between the unripe and overripe leaves, but there were no significant differences (P>0.05) in nicotine content between the ripe and overripe leaves. There were no significant differences (P>0.05) in the reducing sugar levels of KRK 26 R between the unripe and ripe leaves, but there were significant difference (P<0.05) in the reducing sugar levels between the ripe and overripe leaves. On variety T 76 there were no significant differences (P>0.05) in nicotine content between the unripe and ripe leaves, but there were significant differences (P<0.05) in nicotine content between the unripe and overripe leaves, and between the ripe and overripe leaves. On the reducing sugars levels of variety T76 there were no significant differences (P>0.05) between the unripe and ripe leaves but there were significant differences (P<0.05) between the unripe and overripe leaves and the ripe and overripe leaves. In conclusion, the study showed that nicotine levels in both varieties were within the accepted range of 2–5 % and did not seem to be affected by the stage of leaf ripeness. The reducing sugar levels of both varieties on unripe and overripe leaves were far less than the accepted range of 15-30% and only the ripe stage levels were within the accepted range of 15-30%. It is therefore important that growers reap leaves at the ripe stage only in order to attain the acceptable reducing sugar levels in their tobacco.