| Seedling is the most fundamental work as well as one of the most important links in flue-cured tobacco production. While floating nursery provides favorable technical support for the flue-cured tobacco seedlings cultivation, the long-term low temperature and insufficient light during seedling cultivation in Luzhou, Sichuan Province have brought great difficulties to flue-cured tobacco seedlings. In response to this situation, the paper compares and analyzes how the four types of seedling cultivation methods influence the quality, growth and quality of tobacco leaves, including conventional floating nursery (control), water heating seedling, air heating seedling, and moist seedling, accordingly further investigating the impact of different heating methods in seedling and their application prospect. The main results are as follows:1、Water heating and moist seedling can better promote the growth of the root and contribute to the well-developed root system.In the maturing period of the tobacco, the root dry weight of the four methods is in the following order:moist seedling>water heating seedling> air heating seedling>control.2、In the three-to-four-leaf stage, the maximum leaf length and the maximum leaf width of the water heating seedling, air heating seedling and moist seedling are significantly larger than that of the control.3、The highest survival rate of seedlings after transplanting is moist seedling, followed by water heating seedling. The two methods have a high survival rate. The revival of seedling of moist seedling and water heating seedling is4～5days earlier than that of air heating seedling. The moist seedling and water heating seedling also enter the resettling stage earlier than the control. The effective leaf numbers in the resettling stage of the four different ways are in the following order:water heating seedling>moist nursery>control>air heating seedling.4、In the resettling stage, the tobaccos cultivated by moist seedling and water heating seedling are the highest. In vigorous growing period, there is a huge difference in tobacco’s agronomic traits among the four methods. The highest plant is cultivated by moist seedling. The second highest is air heating seedling. As for the number of effective leaves, moist seedling has the most leaves.5、The growths of the tobacco after transplanting are basically the same in the four methods. The first time for baking is between July2nd and6th. The tobacco yields of the four methods are between114-127kg/667m2. The tobacco yield of the moist seedling is higher than the control, amounting to127.5kg/667m2.6、There are also some differences in the quality of appearance among those methods. The other three methods achieves7.5points in maturity, which is slightly higher than the control. As for the leaf construction, the moist seedling scores8points which was higher than air heating seedling, water heating seedling and the control. Per chroma, the moist seedling and air heating seedling gain the highest points. Concerning the inner coordination of the chemical composition, moist seedling and air heating seedling have the higher points.7、The cost of moist seedling is almost the same as that of the control. Although water heating seedling and air heating seedling produce direct and obvious seedling effect, the costs are much higher. Considering the economic benefits, moist seedling is a more feasible breeding method in Luzhou.Comparing the nurturing results of seedling, the overall effect of the four different methods ranks in the following order:moist seedling>water heating seedling>air heating seedling>control. Considering the various terrain and climates of Luzhou, different regions may choose the optimal breeding method according to the actual situation and the study results. |
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