Study On Method And Application Effect Of Recurrent Selection In Rice Restorer Line Breeding

In this study, cytoplasmic male sterility of wild abortion (WA) was used as a facility in rice recurrent selection. Many restorer lines, maintainer lines, routine varieties, which contain target character, and a WA male-sterile line, Long Tefu A, were chosen as primitive parents to structure recurrent selection population according to genetic and appearing characteristics. Also, many single cross hybrids or multiple cross combination of different types were gained from these materials. Fine male-sterile plants (r1r1r2r2) selected from each multiple-cross F| were crossed with male-fertile plants (R1r1R2r2) from other multiple cross combination to obtain genotypes R1r1R2r2 R1r1r2r2 , r1r1R2R2 and r1r1r2r2, in which male-sterile plants were 25%. And basic population of recurrent selection was developed from the bulk seeds of male-sterile plants. In every later recurrent selection population, sterile plants (r1r1r2r2) were gotten by method of phenotypic bulk selection, excellent fertile plants (R1r1R2r2) were gotten by method of progeny testing for plants from the recurrent selection population in last cycle. Then, all seeds of sterile and fertile electees were transplanted in an isolation plot alternately and the former was pollinated with the latter. Seeds collected from sterile plants contained different genotype (R1r1R2r2, R1r1r2r2 , r1r1R2r2 r1r1r2r2), in which sterile plants were still 25%. According to this theory, it was possible to use recessive WA male-sterility on rice recurrent selection.The results of our experiment showed that: (1) Ratio of sterile plants is stabilized at 1/4 in every cycling selection population, therefore, there were abundant of sterile plants for phenotypic selecting to structure the next cycling recurrent selection population, it was to say, recurrent selection could go on in every generation using WA cytoplasmic sterility. (2) Among early cycling population, a lot of single plants didn't fit to breeding objective, plant height and heading date varied in a large of range. But, only after one or two selecting cycles, heading date and plant height of most plants had agreed to breed objective, and it showed great function on later selection for economic and quality character. This experiment system of recurrent selection has been proved effective and feasible to the selection of WA restorer line and routine inbred curtivar. (3) By this study, the population and germplasm sink were improved At the same time, new restorer line and excellent cross combination was achieved. Restorer P004 and cross combination 3037 was prominent...