Development of Wide-Compatible Lines by Pyramiding Multiple Neutral Alleles of - Hybrid Sterility Loci.

Since the development of hybrid rice in the 1970s, great success has been achieved in hybrid rice production in China and around the world. The utilization of inter-subspecific hybrid rice has always been considered due to its stronger heterosis characteristics. However, - hybrids face a serious problem of sterility, which hinders the exploitation of their heterosis. In the past decades, the genetic basis of - hybrid sterility has been well studied. It was found that in sterile - hybrids, female sterility was mainly controlled by the locus and male sterility by the , , , , and loci. In this study, we developed wide-compatible lines (WCILs) by pyramiding multiple neutral (n) alleles of the hybrid sterility loci. First, we identified alleles of the loci in single-segment substitution lines (SSSLs) in the genetic background of Huajingxian 74 (HJX74). Then, the alleles of , , , , and loci in SSSLs were pyramided in the HJX74 genetic background. The WCILs carrying alleles at the , , , , and loci showed wide compatibility with and rice varieties. Therefore, the WCILs will be used to develop inter-subspecific hybrid rice with normal fertility.