Study Of Suitable Harvest Dates For Higher Vigor Seed Production Of Hybrid Rice

Seed vigor is one of the seed quality traits that represent Germination ability of the seed in the field, high seed vigor had a fast germination, tidy and with high survival rate, that is important for modern crop production which is mechanization and save time. In order to determine the optimum harvest time of hybrid rice with high seed vigor, field experiment was conducted at the summer of 2014 in Yongan town, Liuyang city, Hunan province. Four selected hybrid combinations:Jinyou 167 (23A * R167), ? you 416(-32A *R416),Y liangyoulhao (Y58S* R9311),C liangyou 608 (C815S * R608) was used. The seeds were harvested every 3 days after pollination to observe seed moisture content, grain weight, protein content, soluble sugar, starch, and seed Shape, to find out the relationship of seed germination and vigor index with other Character, for determine the optimum harvest time of hybrid rice with a high seed vigor, that, to provide reference resources. The main results were as follows:(1)There was significant correlation between accumulation and seed vigor. The result shows the protein content of 10-15% and the fluctuation was less than 2%, thus the total starch content was around 80%, and the fluctuation was less than 7%. Therefore, the relationship between protein and starch accumulation had two functions, and the effect of protein and starch accumulation on germination rate is bigger then seed vigor.(2) This study showed, there was interaction between soluble sugar and seed vigor. The result showed the soluble sugar content is less 10%, after 15-18 days of the seed pollination the soluble sugar content changed lightly in the range of 1%?2% while so the soluble sugar content increased rapidly after 15-24 days of seed pollination. Through the analysis of the late stage of seed development, seed vigor is negatively correlated with the content of soluble sugar.(3) The relationship between seed moisture content and seed weight with seed vigor is significantly different. Therefore, the relationship between seed moisture content and seed vigor had quadratic curve correlations. The regression analysis showed that when the moisture content between 20?30% the seed vigor index of seed is higher, therefore, the relationship between seed grain weight and germination rate had quadratic curve correlation while, the relationship between seed grain weight and germination index and vigor index was linearly. The results showed that, at the maximum grain weight, the seed had maximum germination rate, germination index and the vigor index. Therefore, moisture content and grain weight can be used to determine the basis of high vigor seeds harvested.(4) The relationship was significantly differences between grain length, grain width, gray and seed vigor. Regression analysis showed that the grain length, grain width and seed vigor had a linear correlation, and the correlation was significant, there is relationship curve between the gray of brown rice with germination rate, germination index and vigor index. By means of regression analysis, when Jinyou 167, ? you 416, Y liangyou lhao (Y58S* R9311), C liangyou 608 (C815S* R608) when the seeds vigor was maximum, the value were 170,188,173,176 respectively.(5) During the seed maturity seed vigor was increased to reach the highest value, and then it was decline. The germination rate of Jinyou 167 was higher around 12-21 days after pollination while, seed vigor index was higher between 15?18 days after harvest; therefore ? you 416 seed germination rate was higher during 12-24 days after pollination and the seed vigor index was higher about 15-21 days; thus, Y liangyou 1 in 15 days after pollination had germination rate above 90% and higher vigor index after pollination 15-24 days; subsequently,C liangyou 608 seeds had higher germination rate during 12-21 days after pollination and higher vigor index after pollination 15-21.Based on the above results, the suitable harvest time of hybrid rice with high vigor seeds was 15-20 days after pollination, the seed moisture content between 20-30%, brown rice grain width, length to reach the maximum value, the gray of seed value between 170-190, grain weight is close to or reach the maximum grain weight.