Tar Delivery Difference Among Flue-cured Tobacco Leaves from Different Stalk Positions of Different Eco-geographical Areas in Hunan

The tar deliveries of 180 flue-cured tobacco samples from 3 stalk positions(upper, middle and lower) grown in Hunan tobacco growing areas were analyzed.The results showed that: the means of tar deliveries of upper, middle and lower leaves were 19.9, 16.9 and 12.71 mg/cig., respectively, whose main distributing ranges were 17.8-20.8, 13.4-16.0 and 10.2-14.0 mg/cig., respectively.For same stalk position, the tar deliveries of leaves from Northwest Hunan were the highest, and the difference was significant between ecological areas;the tar deliveries of leaves grown in Xiangxi was relatively higher, those in Yongzhou and Changsha were relatively lower, and the difference was significant or extremely significant between areas.The eco-regionally tar deliveries of upper leaves declined gradually from northwest to southeast, and increased initially and then decreased gradually from southwest to northeast;for middle leaves, which declined initially and then increased from northwest to southeast, while from southwest to northeast were on the contrary;for lower leaves, which decreased initially and then increased from northwest to southeast, and declined from southwest to northeast.