Effect of Water Control before Transplanting and Rooting Powder Treatment on Tobacco Seedling Quality and Physiological Properties at Green Stage

Cultivating strong seedlings is an important guarantee for the production of high-quality flue-cured tobacco, while there are many disadvantages in tobacco floating system that is commonly adopted in China. To improve the tobacco floating system, with Xiangyan No.3 as experimental material, the effects of water control before transplanting and rooting powder treatment on tobacco seedling quality and physiological properties at green stage were investigated. The results showed that： （1） water control showed small influence on tobacco seedling quality, while rooting powder treatment and water control ＋ rooting powder treatment showed great influence on tobacco seedling quality, mainly represented by reduced plant height, thickened stem and increased dry matter accumulative amount; （2） water control before transplanting and rooting powder treatment all improved leaf chlorophyll content and root vigor of tobacco seedlings, and the effect of water control ＋ rooting powder treatment was best, followed by rooting powder treatment and water control; （3） all treatments increased the nitrate reductase and invertase activity, and reduced the MDA content of tobacco seedlings, and the effect of water control ＋ rooting powder treatment was best, followed by rooting powder treatment and water control. Mean- while, the treatment effect 10 d before the transplanting was better than that 5 d before the transplanting. In overall, the improvement effects of water control 10 d before transplanting ＋ rooting powder treatment on tobacco seedling quality and physiological properties at green stage were the best.

Effects of Bamboo Vinegar on Seed Germination and Seedling Growth of Different Flue-cured Tobacco Varieties

[Objective] The present experiment was conducted to study the effects of bamboo vinegar on seed germination and seedling growth of different flue-cured to- bacco varieties, so as to provide some references for its application in tobacco pro- duction. [Method] By using indoor culture dish method and greenhouse seedling- raising plate culture,four different concentrations of bamboo vinegar dilution （50, 100, 200 and 400 times）were designed and clean water was used as the control （CK）. The germination indices of Yunyan 97, Guiyan 2, Jiucaiping 2 and Bina 1 were de- termined after seed germinating. The seedling growth indices of Yunyan 97 were investigated after 10 days of spaying bamboo vinegar on seedling leaves at the 3r~ time. [Result] Compared with CK, different bamboo vinegar dilutions could inhibit the seed germination and seedling growth of all flue-cured tobacco varieties. The seed germination rate and index, vigor index, whole length, root length, stem length and fresh weight of seedlings of all varieties presented decreasing trend to varying de- grees, moreover, most of them reached significant level. Compared with CK, spray- ing different concentrations of bamboo vinegar dilution at the seedling stage could improve the quality of seedlings. In all bamboo vinegar treatments, the plant height, the maximum leaf length and root volume under 100 times dilution treatment were the highest with 3.36 and 10.14 cm, and 0.92 ml, respectively. And the stem girth, dry weight and the maximum leaf width of seedlings under 400 times dilution treat- ment also showed the highest with 1.82 cm, 0.262 g and 5.74 cm, respectively. [Conclusion] Supplying different concentrations of bamboo vinegar solution on culture dish could inhibit the seed germination and seedling growth of flue-cured tobacco, while spraying 100-400 times bamboo vinegar solution to leaves could promote the seedling growth and improve the quality of Yunyan 97 to varying degrees.

The Application of Seedling Nursing on Moist Trays and Fermentation Heating Using Farmyard Manure Methods in High-altitude Tobacco Areas of Fenggang County

To solve the problems of long seedling culture time and poor quality of tobacco seedlings bred by floating culture technique of seedlings in high-altitude tobacco areas, a comparative trial between seedling nursing on moist trays ＋ fermentation heating using farmyard manure and conventional floating culture of seedlings in Fenggang County was carried out in 2013. The results showed that seedling nursing on moist trays ＋ fermentation heating using farmyard manure can improve 4-5 ℃ of pool water temperature, shorten 8 d of seedling age, increase 4.45 cm of seedling height, thicken 0.46 cm of stem girth and make lateral root system developed. The method can shorten the time of floating breeding of flue-cured tobacco,improve the quality of tobacco seedlings, thus it was suitable to popularize in highaltitude tobacco areas of Fenggang County.

Study on Flue-cured Tobacco Young Seedlings Cultivation Technique in Tobacco-producing Areas of Panzhihua

Objective] This study almed to expIore a suitabIe fIue-cured tobacco young seedIings cuItivation technique for tobacco-producing areas in Panzhihua. [Method] The randomized bIock design was used to conduct a two-factor test of fIoating pate and seedIing age. [Result] The young seedIings cuItivation technique re-duced the cuItivation cost by 76.6%; the optimum seedIing age was 45 d; the fIoat-ing pIate with specification of 595 hoIes/pIate couId best improve the cuItivation effi-ciency; and the Ieaf-uncut young seedIings cuItivation technique significantIy reduced the incidence of disease in tobacco pIants. In short, the production benefit of young seedIings cuItivation technique is significantIy higher than that of conventional tech-nique. [Conclusion] Referring to the young seedIings cuItivation techniques in Guizhou and Yunnan and according to the actual situation in tobacco-producing ar-eas of Panzhihua, the fIue-cured tobacco young seedIings cuItivation technique, which was suitabIe for tobacco-producing areas of Panzhihua, was deveIoped. This cuItivation technique can be used to provide tobacco seedIings for under-fiIm cuItiva-tion. In addition, it wiI provide a reference for reducing cuItivation costs, reducing environmental destruction, reducing incidence of disease and improving production efficiency of tobacco Ieaves.

Effects of Warming Seedling Cultivation Technology on Growth, Yield and Quality of Fluecured Tobaccos

An experiment of seedling nursing which used film mulching technology in greenhouse to increase temperature was carried out in the south of Hunan province in 2014. The results showed that the average surface temperature of seedling tray and the average water temperature of nursing pool at 10：00 and 16：00 in treatment1 which used film mulching technology in a greenhouse were higher than that of CK（no film mulching）, suggesting the warming effect of mulching film in a greenhouse is obvious. The growth potential of tobacco seedling is stronger in treatment1 than CK, and tobacco seedling quality index including the fresh and dry weight of stem, leaves and roots increased. Plant height, stem girth and leaves area of the treatment 1 were higher and more than that of CK after transplanting. Squaring,topping and maturity period were slightly earlier in the treatment 1, compared with that of CK. Average yield of treatment 1 was 2 308.8 kg/hm^2, which increased by6.03% and was significantly higher than that of CK,and the output value of the treatment 1 was 50 184.75 yuan/hm^2, which increased by 5.61%.

Study on Selection and Application of New Matrixes for Floating Tobacco Seedlings

[Objective] This study aimed to verify the effects of new matrixes on tobacco seedlings on floating platform or field, and their effects on tobacco leaf yield and quality. [Method] The ratio of peat： carbonized rice hull： perlite： sand in the four new matrixes was 10∶40∶30∶20, 20∶40∶10∶30, 20∶40∶30∶10 and 20∶50∶10∶20, marked as T1, T2, T3 and T4, respectively. The ratio in control matrix was 35∶40∶25∶0. [Result]In formulas T1, T2, T3 and T4, the peat consumption was reduced by 70.1%,41.5%, 41.5%, and 41.5% respectively, which saved 12.5%, 23.1%, 8.2% and 12.8%of the cost. The new matrixes can effectively increase the seedling emergence rate of tobacco. The quality and duration of seedlings in float system with new matrixes showed no difference from those of control matrix. The values of output using the new matrixes were 323.10, 92.25, 39.30 and 2 250.60 Yuan/hm2higher than that of the control. Besides, the proportion of the first- and second-rate tobacco leaves was also improved. [Conclusion] These four new matrixes can be widely applied to raise seedling in a float system, and T4 is the best choice.

Improving Transportation and Transplanting Efficiency of Flue-cured Tobacco by Transportation of Naked Seedlings

[Objective] The aim was to resolve the problem of low transportation efficiency of seedlings,vulnerability of seedling trays and difficulty of recycling.[Method]Naked seedlings were transported with trays and frames to improve transportation and transplanting efficiency.[Result] The transportation of naked seedlings would effectively reduce transportation cost and improve transportation and transplanting efficiency of tobacco seedlings.[Conclusion] The transportation of naked seedlings is suitable to be applied in the region with professional transplanting.

Application of Intensive Closed-type Float System in Tobacco Nursery

Due to the continuous low temperature during the early-nursery period in most tobacco-growing areas in Guizhou Province, the tobacco seed germinate slow-ly, the nursery period is prolonged, the quality of tobacco seedlings are not that good, the transplanting is delayed, etc. A comparative test of intensive closed-type floating-seedling system and conventional floating-seedling system was carried out in this study. The results showed that the intensive closed-type floating system could shorten significantly the nursery period; enhance the growth of tobacco seedlings;improve significantly the appearance of agronomic traits, such as number of leaves, stem height, stem diameter, fresh weight of leaves, etc; increase slightly the chloro-phyl content in seedlings. However, the root fresh weight and root vigor of seedlings nursed with the intensive closed-type float system were lower than that of seedlings nursed with the conventional float system. The intensive closed-type float system had a certain application potential in tobacco production.