Yunyan87 was used as test variety to study the physical characteristics of flue-cured tobacco leaves from three typical altitudes in Bijie city,low altitude(840 m),middle altitude(1 430 m),high altitude(2 100 m).The results showed that at high altitude,tobacco leaf position is negatively correlated with filling value,stalk proportion and leaf width,but it is positively correlated with single leaf weight;at middle altitude,tobacco leaf position is negatively correlated with leaf width,and filling value,stalk proportion and single leaf weight increase first and then decrease with increasing tobacco leaf position;at low altitude,tobacco leaf position is positively correlated with single leaf weight,and filling value,stalk proportion and leaf width increase first and then decrease with increasing tobacco leaf position.At different altitudes,tobacco leaf tension,leaf mass per unit area,leaf thickness and leaf length variant the same,but single leaf weight,leaf width,stalk proportion and filling value variant a little different.The physical characteristics of the flue-cured tobacco leaves from different positions changes relatively great at high altitude and middle altitude,and it changes small at the low altitude,moreover,there is a significant differences between them.

The single-factor randomized block design was used to study the effect of different altitudes on chemical composition in leaves of Bina 1(a new tobacco variety) from 50d to 95d after transplanting to provide a reference for quality improvement of special tobacco varieties in Bijie city.The results showed that the content change trend of starch and aminoacid content in leaves of Bina 1 cultivated fields with different altitudes was the same.The starch content presented a first decline and then rising trend but the amino acid content showed a linear decline trend.Altitude had the significant effect on pigment and reducing sugar content in leaves of Bina 1.In conclusion,Middle altitude ecological environment is benefial to tobacco quality of Bina 1 in bijie city.