Effects Of Water Controling And Hormone Treating At Late Stage Of Floating-seedling System On Growth,Yield And Quality Of Flue-cured Tobacco

In order to overcome the weakness of longer seedling recovery stage in floating seedling system, the effects of water controling and hormone treating at late stage of floating-seedling system on growth,yield and quality of flue-cured tobacco was studied. The main results were as follows:1. Differences in agronomic traits:The agronomic traits of the treatments with water controlling and hormone treating10days (T6) and5days (T5) before transplanting were the best, followed by the treatments with hormone treating5days (T3) and lOdays (T4) before transplanting.2. Physiological and biochemical differences:The best promoting effects on chlorophyll content, root activity, nitrate reductase activity and invertase activity existed in T6and T5, followed by T3and T4. The performance of T1and T2were also better then that of blank (CK).3. Chemical composition differences of flue-cued tobacco:The total sugar content and and reducing sugar content among different treatments took the sequence as T5>T6> T4>T3>T2>T1>T7; T6>T5>T4>T3>T2>T1>T7for potassium and chloride content; T5>T6>T4>T3>T2>T1>T7for starch content; T6>T5> T4>T3>T2>T1>T7for sugar/nicotine ratio, nitrogen/nicotine ratio and potassium/chloride ratio. The nicotine contents in all treatments were a little lower than that of blank (CK).4. Effects on economic traits of flue-cured tobacco:Significant differences in yield, output value and fine quality tobacco leaf ratio existed between different treatments and CK. The economic benefits of all treatments were higher man that of CK. The yield and output value of T6and T5were the highest, followed by T3and T4, and the lowest for CK.In short, the agronomic traits, physiological and biochemical characteristics, eaf chemical composition, the yield and quality in the seedling stage, the rosette stage, vigorous growth stage and mature stage all showed the same results as following:T5(water controlling and hormone application at10days before transplanting)> T6(water controlling and hormone application at5days before transplanting)> T4(before transplanting10d of hormone application at10days before transplanting)> T3(hormone application at5days before transplanting)> T2(water controlling at10days before transplanting)> T1(water controlling at5days before transplanting)> T7(control: traditional floating nursery).