Abstract: The drying characteristic parameters of fresh tobacco leaves affecting water loss rate during curing were screened to provide parameter guidance for constructing the water loss rate model based on quality of fresh tobacco leaves. Different parts of flue-cured tobacco varieties Yunyan 87, K326 and Ekao 2 in Enshi tobacco growing area of Hubei Province were used as experimental materials. Correlation analysis, multiple contribution diagnosis, stepwise regression analysis and dominance analysis were used to explore the relationship between fresh tobacco parameters and water loss rate during curing. The results showed that the parameters of fresh tobacco leaves and water loss rate varied greatly during curing, and the coefficients of variation were 5.98%~18.58% and 14.55%~24.33%,respectively. The simple correlation coefficient showed that correlation of the moisture content, leaf thickness, leaf length, leaf width, main vein diameter in the middle of the leaf, diameter of the main vein of the tip of the leaf, and diameter of the branch vein at the base of the leaf with the rate of water loss in some stages reached a significant level, but there were multiple collinearities among indexes of fresh tobacco. After the collinearities were eliminated by the stepwise regression method （regression equation passed significance test, P < 0.01）, the average contribution degree of each index to each stage of tobacco curing was calculated with the help of the dominance analysis method （DA）. Under the same baking conditions, the leaf thickness, leaf width, leaf base branch vein diameter, leaf tip main vein diameter and leaf middle main vein diameter of fresh tobacco leaves were selected as the key parameters of water loss characteristics during tobacco baking.

Key words: flue cured tobacco, curing, fresh tobacco, water loss characteristics