| The experiment proceeded in the testing ground of Anhui Agricultural University from 2003 to 2004. Three varieties of field-grown cotton, Bt-transgenic bollworm resistant variety Guokang 1 which is be popularized, Simian 3 which is parent of Guokang 1 and Bt+CPTI-transgenic boll-worm resistant variety CCRI 41 were researched for the relations of the growing and physiological characters to yield. The experiment provides theoretic proofs in point for bollworm resistant cotton growth of high yield, great efficiency and high quality. The results of research are as follows. 1. Growth Characters Comparing with Simian 3, Bt-transgenic bollworm resistant cotton Guokang 1 seedling appearing, boll setting, flowing and boll open early. There was a rapid rise in the plant height, fruit branches count and burl count of Guokang 1 during early flowing stage and blossom stage. Bt-transgenic bollworm resistant cotton had an advantage of setting boll in boll stage, but it was weakened in early flower stage. The peak of boll setting appeared in the blossom stage. But the power of boll setting weakened after boll open. Strengthen management to keep the power of boll setting in the bloom of growth, and try to set boll more. 2. Accumulation and distribution of dry matter It was the most rapid speed period of dry matter accumulation for budding to boll setting stage. The dry matter weight of nutrition apparatus and procreation apparatus of blossom and boll stage reached the peak all over the growth period. It showed that Bt-transgenic bollworm resistant cotton flourished in the nutrition and procreation growth of the period, and that the relations of nutrition growth and procreation growth harmonized. It was benefit to get to high yield. But the dry matter accumulation weight of Guokang 1 decreased rather rapid. In particular the dry matter accumulation weight of nutrition apparatus decreased rapidly and it showed to decline early. It was not to advantage to mature to boll open for the back period of Guokang 1. 3. Photosynthetic characters Chlorophyll contents and leaf area index of Guokang 1 reached both the peaks in the blossom and boll stage. Chlorophyll contents and leaf area index of Guokang 1 were superior to Simian 3 from bud stage to blossom and boll stage. Photosynthetic rate of Guokang 1 was the most, being obviously superior to Simian 3. Variety of photosynthetic rate per day appeared in curvilinear changes with single peak in the blossom of Guokang 1. Photosynthetic rate reached the maximum the whole day at 10 o'clock in the morning, and it is bigger 0.83 umolCO2·m-2s-1 than Simian 3. Then photosynthetic rate of Guokang 1 fell step by step, and was smaller than Simian 3 after 16 o'clock in the afternoon. Transpiration and stomata conductance of Guokang 1 were quite high, and cotton plants consumed much water. It affected photosynthesis of cotton. Correlation analysis showed that air temperature, leaves temperature, stomata conductance and transpiration affected most photosynthesis of cotton in the blossom stage. More high air temperature and leaves temperature can quicken transpiration, leading to affect photosynthesis because of consuming much water. So high temperature in summer is the important factor of affecting photosynthesis of Bt-transgenic bollworm resistant cotton. 4. The relations of the growing and physiological characters to yield The weight per boll of Bt-transgenic bollworm resistant cotton weighted more 26.5% than that Simian 3. The bolls per plant had a little more than that Simian 3. Research for yield character that per boll, bolls count per plant and the whole bolls count are important factors to decide the yield. The nutrition apparatus dry weight, photosynthetic rate, chlorophyll contents and leaf area index of bud stage and procreation apparatus dry weight, photosynthetic rate and leaf area index of blossom and boll stage affected most the cotton yield. So enhance management of fertilizer and water in practice. Keep fitting leaf area index, adding photosynthesis and assure cotton of growt...
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