| In order to explore the physiology of drought resistance and main nutrient properties of upland rice and to provide guidance to high-production, high-efficiency of upland rice cultivation and dry farming of lowland rice, three field experiments were conducted. The first one was the upland and lowland cultivation experiment, which included four varieties Upland rice-TANGARA and IAPAR9, Lowland rice XinXiangYou80 and R80.The other two experiments were fertilization and chemical regulation to upland rice-TANGARA. The results were as follows:1. There existed significant differences in yields of different varieties between upland and lowland cultivation. The yield of XinXiangYou80 reach to 8.37 tons per ha, which is extremely higher than that of other varieties. There were significant differences in all varieties under lowland cultivation. The yield decreased markedly under upland cultivation. However the yield of XinXiangYou80 was the highest, TANGARA was the second, R80and IAPAR9 was the third and forth respectively. Among these varieties, the yield of IAPAR9 is lower than that of the others and there was significant difference at 0.01 level. But there was no significant difference between TANGARA and XinXiangYou80. The results showed that the yield of XinXiangYou80 was prior to that of R80 and the lowland rice prior to upland rice. The XinXiangYou80 and upland rice-TANGARA were more suitable for upland cultivation.2. The whole grains per panicle, seed-setting percentage and 1000 grains weight decreased as the result of drought stress. As for the effective tiller number, the upland rice decreased and the lowland rice increased. Among yield components, the effective tiller number had the biggest effect on the yield, which path coefficent was 1.3690; the 1000 grains weight has also effect on yield, the path coefficent was 1.0727; andthe path coefficents of grains per panicle and seed-setting percentage were 0.8298, 0.3378 respectively.3.Developed root system, vigorous roots, middle plant height and growth duration and leaf area of rice variety have stronger drought resistance under upland cultivation. TANGARA and XinXiangYou80 have these properties as well as good agronomical characters. So they are the better varieties to upland cultivation. In addition, the growth duration, plant height, tillering, leaf area, dry matter accumulation and the quality of rice were influenced by drought stress, the rice quality of all varieties of lowland cultivation is better than that of upland cultivation, whereas the content of protein of rice increased obviously under upland cultivation.4.The higher the relative photosynthesis rate and transpiration rate, the stronger the drought resistance. The relative electric conductivity of almost of varieties under upland cultivation was bigger than that of lowland cultivation during panicle initiation and yellow-ripen stages. There were close relationship between the drought resistance of rice and the amount of exudate, the root activity and the nitrate reductase activity (NRA).5.The result of comprehensive evaluation showed that the highest was TANGARA (4.06), significantly higher than the other varieties. XinXiangYou80 was the second (3.21), which higher than that of IAPAR9(3.19), the lowest was R80(2.72). Thus the upland rice TANGARA has stronger drought resistance, IAPAR9 has strong drought resistance in physiology but the agronomical characters were poor. The XinXiangYou80 has medium level drought resistance and good yield characters, R80 was poor in the two aspects. The result was in concide with the field performance.6.The total content of Nitrogen of stem in milky stage affected on the theoretical yield, followed by that of panicle initiation stage ,the path coefficents were-0.7457 and 0.4277 respectively. The biggest amount of accumulation of N, P was treated by coated fertilizer, but the biggest amount of accumulation of K was treated by single-element fertilizer. The lowest amount of accumulation of those three elements was that of comm... |
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