| This study was completed in Fujian Institute of Tobacco Science (located in Huanxi Town, Fuzhou). Flue-cured tobacco cultivars CB-1 and K326 were used as experimental materials. There were three different transplanting periods:January 21, February 17, March 6. All the transplanting periods contains CB-1, but only two of them contain K326, January 21 and March 6. In total, there were five treatments overall:C01-21, C02-17, C03-06, KO1-21, K03-06. We compared flue-curred tobacco in different transplanting period in respect to matter content,smoking quality and biomass. The climatic factors of different treatment and the quality of flue-cured tobacco were analyzed by correlation and regression analysis to find the relationship between them, in an effort to understand the factors which made Fujian flue-cured tobacco become strongly aromatic than before and find solution for this issue.The average monthly temperature of test fields during tobacco planting (from January to July) was 16.1℃, the average monthly soil temperature was 18.0℃, rainfall was 1327.1mm, sunshine duration was 2024.6h and that there was not badly meteorological disaster. Differences between each climatic factors treatment were significant. Delayed transplanting treatment gives more favorable conditions to produce high-quality flue-cured tobacco, the 5-day average temperature of January 21 and February 17, are 2.6℃ and 4.7℃ higher than the first treatment. Due to delayed transplanting treatment, growth period duration was significantly shortened, hence the rainfall, the solar duration, the cumulative value of photosynthetic radiation and accumulated temperature of each treatment became less. However, each treatment harvest period was progressively higher in 1.5-2℃ than the average temperature of the pre-transplant treatment.The biomass of flue-cured tobacco increased in correlation with transplanting delayed conditions, and the effective number of leaves, leaves area, plant height and stem girth progressively increased with transplanting delayed. Due to early planting and cold weather, samples under K01-21 treatment flowered earlier and its vigorous growth period became shortened, leading to less dry biomass, and with narrower leaves. After delayed transplanting, the biomass of K03-06 treatment increased significantly. Conversely, samples under CB-1 treatment flowered regularly and were prevented from weather flecks, although its production was lower, but the differences between C02-17 and C03-06 against C01-21 were not significant. The result shows that 10-days average UV radiation and average temperature can affect about 95% R2 of the regression equation of tobaccos’ root, stem and leaves’ dry biomass; For same tobacco, the leaves can hold lower temperature than its root, while CB-1 can grow better than K326 in low temperature. The average temperature, average soil temperature, radiation and >10℃ accumulation temperature of tobacco mature period were significantly positively correlated with the number of tobacco leaves, leaves area and height.After the delayed transplanting, total potassium and nitrogen of CB-1 increased, as well as the sugar/nicotine, potassium/chlorine and total sugar/reducing sugar ratios, while nicotine, total sugar and reducing sugar content and nitrogen/nicotine ratio decreased. However, after delayed transplanting, those sugars mentioned above in K326 appeared to decrement, as well as sugar/nicotine, nitrogen/nicotine ratios. Nevertheless there was a significant increase in nicotine, total nitrogen and total potassium content, potassium/chlorine and total sugar/reducing sugar ratios. Chlorine content of both varieties of tobacco exhibited regular changes within the delayed transplanting period, even so there are significant differences in leaves belonging to each part of the tobacco plant. UV radiation, average temperature and accumulation temperature had an important influence on tobacco leaves’ content, and the result of regression equation shows that K326’s contents rely more on higher average temperature and accumulation temperature. Flue-cured tobacco’s contents rely mostly on sunshine duration, radiation and accumulation temperature during vigorous growing and mature period.After the delayed transplanting, the production, production value and rate of high quality flue-cured of tobacco became higher. The rate of high quality flue-cured is mostly depend on vigorous growth period sunshine duration, root-extended period and field condition>5℃ accumulation temperature; the production and production value were mostly depent on mature period UV radiation intensity and field condition> 5 ℃ accumulation temperature. Flue-cured tobacco smoking tests results show that early planting lead to a Qi-Xiang style, gave to a greater extent an adequate aroma, reduced its irritation and got the highest score; after delayed transplanting, the style changed to Nong-Xiang, aroma quality and smoke volume reduced, while the momentum and irritation increased, resulting in a lower smoking score. C02-17 treatment had the lowest scores of all treatments. According to the relevant regression and path analysis, the average temperature and average intensity of ultraviolet radiation in mature samples can significantly influence the Qi-Xiang style of tobacco. When the average temperature and UV radiation intensity was higher the tobacco became closer to Nong-Xiang style.The average temperature during mature period had the most important affect on odor style.Delayed transplanting can hardly affect rosette stage pigment content, while the pigment content of vigorous growth period increased with transplanting delayed; the mature period pigment content of CB-1 firstly increased then decreased with transplanting delayed. But to K326, it kept decreased. The pigment content was mostly affected by >0℃ and >5℃ accumulation temperature. Photosynthetic parameter and Chlorophyll Fluoresence parameter seem to have not regularily change with transplanting delayed, but Pn change with pigment content.To sum up, delayed transplanting can keep tobacco away from cold damage, in favour of increasing tobacco production, production value, rate of high quality flue-cured; but at the same time, delayed transplanting would make flue-cured change from Qi-Xiang style to Nong-Xiang style.CB-1 is more cold-resistant than K326, it can grow well during cold temperature. Early transplanting only make a non-signficantly decrease to CB-1 production and quality, but make flue-cured significantly Qi-Xiang style; K326 grow better in the warmer environment, early transplanting will badly decrease its production and quality. This indicates that it is not good to early transplant k326 for extrude Qi-Xiang style. |
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