Effects of transplanting date on the quality of upper leaves and economic characteristics of flue-cured tobacco in Longyan

In order to improve the usability of upper leaves of flue-cured tobacco, and to explore effects of transplanting date on the quality of upper leaves and economic characteristic of flue-cured tobacco, the flue-cured tobacco variety Yunyan 87 was used as the test material, and field experiments with different transplanting dates were conducted in Longyan, Fujian in 2021, 2022 and 2023. The influences of meteorological factors and transplanting date on the growth and development, quality of upper leaves, and economic characteristics of flue-cured tobacco were analyzed. The results showed that: with the delay of transplanting date,1) The temperature in the growth period of flue-cured tobacco increased, the cumulative sunshine hours in maturity period decreased, and the effective accumulated temperature was basically constant from transplanting date to the budding stage. 2) The growth duration of tobacco was shortened, the stem height, number of leaves and leaf width of upper leaves of flue-cured tobacco increased.3) The content of nicotine of upper leaves decreased, the contents of total sugar and reducing sugar of upper leaves increased. 4) The main agronomic traits and yield had a high correlation with effective accumulated temperature, sunshine duration in root spreading period, sunshine duration in fast growing period. 5) The chemical composition of tobacco had a high correlation with sunshine hours and precipitation at maturity. 6) The appearance and sensory quality of the upper tobacco leaves and economic characteristics of flue-cured tobacco were better when transplanted in early February. Properly delaying transplanting to early February could improve the usability of upper tobacco leaves and the economic characteristic of flue-cured tobacco in Changting of Longyan, Fujian Province.