Investigation On Utilizing The Heterosis Between Indica And Japonica Rice Of Three Lines

Intervarietal hybrid of three lines is still the main types to utilize the heterosis in rice in production now. By three lines to utilize the heterosis between indica and japonicarice and accelerate t he grain yield of rice is worth of exploring way and is likely to succeed. In this article discussed the questions on utilizing the heterosis between indica and japonica rice of three lines, such as the genetic effects of different male sterile cytoplasms, the relationships between restorers and maintainers of the three lines of indica and japonica rice, the stability and flowering habit of the japonica CMS line with different male sterile cytoplasms, were discussed. The research on hybrids between the MS lines with WCG and the R lines with WCG were conducted.1. Three types of isonuclear alloplasmic CMS lines with same genetic background were applied to study the cytoplasmic effects of CMS on eight major characters of rice hybrids. The results showed: (1) Significantly negative effects were observed on seed-setting percentage, filled grain number per panicle, grain yield per plant, plant height. The cytoplasmic effects on heading stage, panicle number per plant, spikelet number per panicle and 1000-grain weight were not significant. (2) The negative effects of different sterile cytoplasms were different, the cytoplamic effects of BT type were much smaller than HL and WA types, the cytoplamic effects of WA type were the biggest. Because the cytoplamic effects performenced only on the traits relating to the sterility, The hybrids between A lines restored easily and R lines with strong restoring ability can increase the seed-setting and avoid or minish the cytoplamic effects.2. By crossing the A lines with different CMS and the R lines of indica and japonica varieties, the research on the relationships between restorers and maintainers of the three lines of indica and japonica rice was conducted. The results showed: (1) The R lines for WA-cytoplasm of indica rice can restore the WA-CMS lines of japonica riceand restored the BT-CMS lines much better than WA-CMS lines of japonica rice; the R lines for BT-cytoplasm of japonica rice couldn't completely restore the CMS lines with WA-cytoplasm and HL-cytoplasm of indica and japonica rice. (2)The BT-CMS lines were more easily restored than HL-CMS lines, HL-CMS lines were more easily restored than WA-CMS lines. By crossing the the R lines with WA-cytoplasm of indica rice and wide compatibility varieties, the technical strategy of breeding for R lines with WCG was brought forth.3. The study on the sterility, restorable character, flowering habit and outcross rate of three types of isonuclear alloplasmic CMS lines with same genetic background was conducted. The results showed :(1) Most pollens of BT-CMS and HL-CMS lines were mainly stained-abortion, all pollens of WA-CMS lines were typical-abortion, the sterility of them was stable; self-seed setting rate of zhenxiqiuguang A and liuqianxin A was 0.06% and 3.72 , respectively, the sterility o f them was the most unstable. (2) Flowering time and flowering season of BT-CMS lines were close to their maintainers. Flowering time of HL-CMS lines was little later than those of maintainers, flowering season was the similar to the maintainers, flowering time of WA-CMS lines was distinctly lagged, flowering season was obviously prolonged, flowering season was not concentrated; The outcrossing rate of BT-CMS and HL-CMS lines were obviously higher than WA-CMS lines. (3) The restored ability of BT-CMS was the best, WA-CMS was the most difficult. In order to solve the problem that the sterility of BT-CMS was unstable and the cytoplasm was unitary in application of Hybrid Rice at precent time, we promoted the assumption about using the HL-CMS lines replacing BT-CMS lines.4.The research on the combination of the breeded CMS lines integrated WCG and the R lines in recent was conducted. The results showed:(l) The characters of plant height, heading stage and biological yield of intersubspecific hybrids was better than that of intervarietal...