1909 flue-cured tobacco samples in 12 provinces were stochastically collected to detect their stem ratio.The results showed that stem ratio of flue-cured tobacco leaves had obvious regional differentiation,the stem ratio of flue-cured tobacco leaves in northern area including Heilongjiang,Jilin and Liaoning was obviously lower than that in the others;the stem ratio of flue-cured tobacco leaves in southern area,including Hunan,Jiangxi,Fujian,Hubei and Shanxi was notably higher than that in the others;the stem ratio of flue-cured tobacco leaves in area,including Guangxi,Shandong,Henan and Sichuan was in a middle position.In southern area,the stem ratio of flue-cured tobacco leaves was markedly higher along with the decrease of position;In the middle area,the stem ratio of flue-cured tobacco leaves was higher along with the decrease of position.The stem ratio of all area remarkably varied in different years.Several factors influencing stem ratio of flue-cured tobacco leaves were also discussed in the article.

In order to find out the difference in chemical composition between tobacco with different flavor types and their effects on smoking quality,106 fluecured tobacco samples from west Fujian and middle Jiangxi were analyzed and their smoking quality and flavor style were identified.The results showed that the contents of nicotine and total nitrogen in tobacco with dominant flavor type in west Fujian and middle Jiangxi were far lower,while the contents of reducing sugar and total sugar,the ratios of sugar to nicotine and nitrogen to nicotine were far higher than those in non-dominant flavor type tobacco.The closer the flavor type to fresh aroma note,the lower the contents of nicotine and total nitrogen and the higher the contents of reducing sugar and total sugar would be.The ratio of sugar to nicotine was the most important factor affecting the flavor quality of tobacco leaf,nicotine content was the major factor,and the ratio of nitrogen to nicotine the next,which affected flavor quantity,offensive taste,aftertaste,irritation,strength and smoking quality of tobacco.The nicotine content was the major factor,and ratio of sugar to nicotine the next,characterizing the typical fresh flavor style of tobacco.Therefore,in west Fujian and middle Jiangxi tobacco growing area,nicotine content is an essential factor affecting smoking quality of flue-cured tobacco,and the ratios of sugar to nicotine and nitrogen to nicotine are also important influence factors.