Screening and identification of wide compatible BLB-resistant rice restorer lines

[Objective]The present experiment was conducted to provide scientific experimental data for utilization of disease resistant genes in wild rice(Oryzae rufipogon) using marker-assisted selection(MAS) and also to provide desirable target parental lines for breeding super hybrid rice and source parental lines for selecting new restorer lines.[Method]The bacterial leaf blight(BLB) resistance gene donor Zhongye 5112 was crossed with the acceptor wide compatible restorer line Gui 649 for selection of their 35 F4 offsprings which were detected by using PCR-based molecular marker RM206,closely linked to BLB resistance gene Xa23.The field inoculation tests of BLB were also performed at the same time.[Results]Amongst 35 F4 hybrid offsprings,13(11 japonica and 2 indica) showed potential of BLB-resistance,wide compatibility and better comprehensive agronomic traits.The allele of Xa23 appeared in the donor Zhongye 5112 and its 13 F4 offsprings,while it was absent in acceptor Gui 649 and other 22 offsprings.The field artificial inoculation results indicated that amongst 37 rice lines,18 lines showed moderate BLB-resistance except for Zhongye 5112,which proved that these lines contained Xa23 gene.Furthermore,the 13 lines with gene Xa23 were crossed to indica and japonica tester varieties and male sterile lines for evaluation of their wide compatibility and hybrid heterosis.The results showed that 12 lines with Xa23 gene had wide compatibility based on the seed setting rate of their F1 hybrids.As compared to control variety Shanyou 63,3 hybrid combinations with super high yield and desirable hybrid heterosis,viz.,Longtefu A×100-1-4,Longtefu A×08262-2-1 and Longtefu A×08278-1-1 were identified for planting in rice producing areas of Guangxi.[Conclusion]The results of marker assisted detection of BLB resistance in different rice lines were coincided with those of field artificial inoculation,which indicated that the gene Xa23 could be detected with PCR-based molecular marker RM206 used in this study.The experimental data could be used for utilization of disease resistance genes of wild rice(Oryzae rufipogon) through marker assisted selection(MAS) .Thirteen elite lines selected in this study can be used as desirable target parental lines in breeding super hybrid rice and as source parental lines in selection of new restorer lines.