Abstract: The tobacco planting experiment was conducted using K346 as the material at tobacco base of Mile County of Yunnan province in 2001 in order to improve economic benefit and quality of flue-cured tobacco and enhance the adaptability of flue-cured tobacco to climate change. The agronomic character, economic benefit and chemical composition of flue-cured tobacco, and meteorological conditions in the different transplanting dates were analyzed for obtaining the suitable transplanting date. The results indicated that temperature and precipitation is suitable to growth of flue-cured tobacco transplanted on April 20 and 30 and May 10, so is on May 20 and 30. However, sunshine duration and accumulative temperature (≥10 ℃) is not suitable to growth of flue-cured tobacco transplanted on May 20 and 30. The meteorological conditions are favorable to growth of flue-cured tobacco transplanted on April 20 and May 10, while those are not favorable to that transplanted on May 30. The meteorological conditions from April 20 to May 10 at tobacco bases of Mile County are similar to that of the foreign high quality tobacco region. However, similarity extents of meteorological conditions between tobacco bases in Mile County and in the foreign base with high quality tobacco region are lower on May 20 and 30 than from April 20 to May 10. Appropriate early transplanting could increase leaf area index, plant height, stem circumference and stem length. With deferring the transplanting date, tobacco yield, the proportion of better quality tobacco and economic income increase firstly and then decrease. The optimal transplanting dates are on April 30 and May 10, and the chemical indices of tobacco are perfect and the chemical compositions are reasonable. The tobacco transplanted from April 30 to May 10 has the suitable yield and the high quality at tobacco base of Mile County or at tobacco production region with similar meteorological conditions.

Key words: Flue-cured tobacco, Transplanting date, Climate, Agronomic／Economic character, Chemical composition