Study On Mixed-planting Seed Production And Cultivation Of Hybrid Rice

In present research, using the different ratio between female parent C815S and male parent YH9113 (Yue hui 9113) during the mixed-planting seed production of a two-line hybrid combination CLY343 (C Liangyou 343), the leaf growth, daily flowering habit, stigma exsertion rate and pollen density as well as yield components of the mix-planted seed production were investigated; comparative analysis of the plant-leaf type, growth period, photosynthetic utilization, grain yield and quality of the F1 generation were also studied. The major results are as follows:1. The growth period of C815S and YH9113 in the mixed seed production presented to be consistent with that in the conventional production, during which the first planted male parents were easy to be affected by the early cold weather resulting more obvious deviation of the leaf emergence rate. But for the second planted parents, there was no difference as for the leaf emergence.2. The unilateral and bilateral stigma exsertion rate increased as the proportion of C815S decreased in mixed-planting seed production.3. A statistically significant difference was found for the pollen density when using the different parental line's ratio. Mixed-planting increased the probability of pollination by distributing the pollen more uniformly. The greater proportion of YH9113 accounted in the mix population, the higher density the pollen was. There was a significantly positive correlation between pollen density and the seed set percentage.4. Among the three parental ratios,1:5 showed the highest yielding, which was a little bit higher than that in conventional production. In the mixed-planting production, with the increase density of female parent C815S, the permeability condition of the field became worse, seed set percentage and grain yield decreased. Therefore, to increase the mixed-planting seed production, rational close planting and improvement of field permeability was the main cultivation measures.5. When the hybrid CLY343 and YH9113 were mix-planted by the ratio of 3:1,6:1 and 9:1, its growth period was the same as the controls'; there was a slightly decrease for the plant height of the mixed-population at the ratio of 3:1.6. By mixed-planting the F1 and male parent YH9113, the whole photosynthetic utilization could be improved. In the three different ratios compared with the control CLY343, the SPAD value was considerable high; even higher than that of the male parent YH9113.7. Among the three different ration of mixed planting,3:1 indicated the highest yield output which could result in high seed production. But it was not significant compared to the control CLY343.8. When the ratio between the hybrid and male parent was at 3:1, the grain quality was better than that of the two controls with a decrease of amylase content by 1.31% and 3.91%, respectively, reaching the standard of fine quality rice.