Studies On The Source-sink Relation And Cultural Regulation Of Tow-line Hybrid Medium Rice

In western Hunan, the source-sink characters and dry matter production ability and high-yielding cultivating methods have been studied. The main results are as follows:1. The two-line hybrid combinations represent good growth adaptation. The average grain yield of tested hybrid combinations is 9597.2 kg/hm2, 4.39% higher than that of control.2. The "source" of two-line hybrid combinations possesses advantages to some extent, but their sink capacity is not predominant visibly. The maximum LAI of tested combinations is 7.65 in average, 1.08 higher than that of control. Theoretical sink capacity is 12821.7 kg/hm2 in average, similar to the control. The ratio of spikelet number to leaf area, the ratio of filled grains to leaf area, the ratio of grain weight to leaf area is lower than that of the control.3. The nutrients accumulated in leaves and leaf-sheath of two-line hybrid combinations are higher during early and medium stages, and the transition of the nutrients to panicles is adequate. The average dry matter weight per hill is 40.5g at flag-leaf full developed stage, and average weight of stem, leaf and leaf sheath per hill is 40.4g, 16.72% and 18.39% higher than that of the control respectively. The transporting amount of dry matter of stem and leaf sheath to panicles is 15.9g per hill in average, 15.55% higher than that of the control. The average transport ratio is 37.8%, which is lower than that of the control.4. The strategies for high-yielding cultivation of two-line hybrid combinations in mountain areas of western Hunan include: improving plant type at early and medium stages; keeping ideal population for high solar utilization at late stage; increasing source and sink, biological output and harvest index synchronously. Key methods of high-yielding cultivation include: sowing at suitable time; raising sturdy seedlings; arranging density reasonably; fertilizing scientifically; irrigating intermittently; controlling insects and pests integratedly; adopting suitable chemical regulations.