Rice male sterile cytoplasm and fertility restoration

摘要

This paper summarizes status of research in rice male sterile (MS)cytoplasm and fertility restoration in China. Hundreds of MS lines,including indica and japonica rices, glutinous rice, early-, medium-, and late-maturing rices, have been developed. Twenty-two types of MS lines have been derived from nucleus substitution backcrosses between ecotypic strains of wild rice and cultivars. About 20 types of japonica MS lines have been derived from substitutional backcrosses between varieties of indica and japonica rice.According to genetic properties, morphology of sterile pollens, and relations between restorers and maintainers, the MS lines are classified into three groups: 1) MS lines of wild abortive (WA) and similar types,2) MS lines of Hong-Lien types, and 3) MS lines of Dian 1, Dian 3, and BT types. Hybrid rice derived from MS lines of WA types have been used in commercial production in China for 12 yr on nearly 60 million hectares.The MS lines of WA,Gam, D, Hong-Lien, Dian 1, Dian 3, and BT type currently are used in hybrid rice production.Some investigations indicated that the genetic characteristics of WA type sterile cytoplasm were rather stable. And the studies on 8 sterile cytoplasms including WA, Liuye, Gam, Hong-Lien, Dian 1, Dian 3, and BT type indicated that sterile cytoplasm reduced the productive capacity of hybrids in contrast to normal cytoplasm of the maintainers. The restorers of the MS lines used in production were obtained mainly by screening and cross breeding.Varieties possessing restoring ability for WA type MS lines are concentrated in low latitudes of Southeast Asia and South China. For the MS lines of WA type which belong to indica sporophytic sterile type, their restorer variety IR24 contains two pairs of dominant genes- (R 1 R 1 R 2 R 2 ). R 1 R 1 comesfrom Cina, a late indica variety in China, and R 2 R 2 comes from SLO 17. The restorers of MS lines of Dian 1 type, which belong to japonica gametophytic type, contain a pair of dominant restoring genes allelic with those of the BT type. Different genetic backgrounds of parents and varied growing conditions of hybrids have some effects on the restoring ability of restorer genes.