Effects of harvest maturity on yield and quality of middle and upper leaves of flue-cured tobacco NC297 and NC102

In order to research the effects of harvest maturity on yield and quality characteristics of middle and upper leaves of flue-cured tobacco NC297 and NC102， the appearance quality， economical characteristics， chemical components of cured tobacco leaves with different harvest maturity were studied. The results showed that harvested， in 26 d after topping， there were the best economic traits and appearance quality for middle leaves of both this two cultivars. and， there were the harvested in 47 d after topping best appearance quality for the upper leaves of the two cultivars， while harvested in 54 d and 47 d after topping， there were the best economic traits for flue-cured tobacco NC297 and NC102， respectively. In the main chemical components， the middle leaves harvested in 20 d after topping of flue-cured tobacco NC297 were more harmonious， which accorded with that obtained by the local practice， and in 26 d after topping for the flue-cured tobacco NC297； while in 54 d and 47 d after topping for the upper leaves of NC297 and NC102， respectively. It was concluded that the optimum harvest time was 26 d after topping for the middle leaves of the two cultivars， while 54 d and 47 d after topping were the suitable harvest time for upper leaves of flue-cured tobacco NC297 and NC102， respectively.