The Comprehensive Evaluation Of South Africa Isolation Seedling Mode In Tobacco

The thesis studied three different seedling culture modes of Nicotiana tabacum including South Africa Isolation seedling, the floating seedling and temporary planting seedling though seedling quality, seedling-rearing cost, agronomic characters, chemical components, yield and economic characters. The main results showed as follows:1) The different seedlings had great influence on seedling quality. The germination rate and biomass of root, stem and leaf of the South Africa isolation seedling was much higher than those of the other two approaches. The South Africa isolation seedling had well developed root system, robust stem, more leaves numbers, a strong resistance to disease. Africa Isolation seedling needed lower seedling-rearing cost, because of lower land rental fee and labour cost.2) Because Africa Isolation seedling had short seedling stage after transplant, rapid rate of leaf emerging, strong fertilizer absorption ability, It promoted the growth of tobacco plant. Compared to those of the other two seedling approaches, South Africa Isolation seedling improved agronomic characters during the tobacco field growth phase.3) Africa Isolation seedling significantly increased yield, high quality leaf proportion, average price and output values of tobacco. Total economic characters were:Africa Isolation seedling> temporary planting seedling>the floating seedling. Tobacco chemical component contents of different part leaves of Africa Isolation seedling were appropriate to high quality cigarette production.4) The Sehmueks number of different part leaves respectively was1.91for lower leaves,1.82for middle leaves and1.7for upper leaves. The chemical composition of tobacco leaves was harmonious, industrial availability of tobacco leaves was best.