杂交水稻组合选配的理论和实践

The Theory and Practice in the Breeding of Hybrid Rice Combinations

双亲的遗传差异是产生杂种优势的基础，依此理论来指导实践。回顾了我国杂交水稻组合选配的成就。

Under the guidance of the theory that the parental genetic difference is the basis of heterosis ofF1 hybrids,in breeding of indica hybrid rice, the improved early indica varieties from Yangtze River Valleywere Chosen as the male-sterile maintainers to develop CMS lines,and the indica varieties(lines) from thesoutheast Asia were used to screen and breed restorer lines. The indica hybrid combinations such as Nanyou2,Weiyou 6 thus developed are of geographical distance and generally yield 20% higher than improved conven-tional indica varieties.The japonica hybrids,e.g.Liyou 57 and Xiuyou 57 were developed by crossing theCMS lines which were bred with japonica varieties from Japan with the restorer lines developed by hybridiza-tions between indicas contained the R genes and japonicas.Because of the narrower parental genetic difference,they yield only about 10% higher than improved conventional japonica varieties.Bay way of the parental im-provement,a group of new early-and medium-maturing hybrids such as Weiyou 64,Weiyou 49,ShanyouGui 8 and Shanyou 63 were released in″The Sixth Five-Year Plan″(1981～1985);Weiyou 1126,Weiyou46,Jiangyou Gan 11,Weiyou 46,Shanyou 10,Shanyou 77,Shanyou Gui 99,Shanyou 3550 and Shanyou Gui44 etc., the combinations with different maturities and somewhat improved resistance and grain quality,weredeveloped in″The Seventh Five-Year Plan″(1986～1990);and the rice hybrids with fine grain quality such asBoyou Gui 99 and Jinyou Gui 99 were bred in″The Eighth Five-Year Plan″(1991～1995).Since the parentalgenetic difference can be widened via two-line MS lines which do not need R genes to restore their sterility,the two-line hybrid rice has a greater yielding potential.In the breeding of hybrid rice combinations,atten-tion should be also paid to breeding combinations in line with the local conditions of various rice growingreglons.