Variation Analysis of Sugar/Nicotine Ratio in Flue-cured Tobacco Leaves from Main Growing Areas in China

742 samples were analyzed to investigate the distribution of sugar/nicotine ratio in flue-cured tobacco leaves among different areas, varieties and grades. The results indicated that:sugar/nicotine ratio in the samples ranged widely from 2.47 to 31.77 with the average value of 10.45 and variation coefficient of 45.31%. The samples with sugar/nicotine ratio in the range of 6 to 10 accounted for 39.30% of the total samples. The sugar/nicotine ratio of Heilongjiang tobacco leaves reached 16.18, while that of Shaanxi and Chongqing was 5.81 and 7.18, respectively. With the average value of 16.88, the sugar/nicotine ratio of cv. Longjiang 911 was the highest; while the sugar/nicotine ratio of NC89 was the lowest with the average value of 8.51. The grades in the order of sugar/nicotine ratio were X2F>C3F>C2F>B2F. There was significant different among leaves of different areas, varieties and grades. Correlation analysis showed that the correlation between sugar/nicotine ratio and other main chemical components in tobacco differed significantly among growing areas and grades.