Improving rice restorer line Yuehui 826 by marker-assisted selection(MSA)breeding technology

ObjectiveHybrid rice restorer line Yuehui 826 was improved to increase its resistance to rice blast and bacterial blight and enhance the rice quality in order to provide parent for hybrid rice combination with disease resistance.MethodMaterial Z1103 with rice blast resistant genes Pi1 and Pi2,bacterial blight resistant genes Xa23 and waxy gene Wx was donor parent,and hybrid rice restorer line Yuehui 826 was receptor parent. Molecular marker assisted selection technique and pedigree breeding were combined to improve disease resistance and rice quality of Yuehui 826 with four exogenous genes. The resistance to rice blast and bacterial blight,and rice quality were also detected.ResultThrough SSR molecular marker detection,rice quality analysis and field resistance identification,six improved inbred lines with Yuehui 826 as genetic background containing target genes were obtained. Through the further agronomic traits screening and restoring ability test,a soft rice strain containing genes Pi1,Xa23 and Wx was selected and named Yuehui 88 in the early season of 2014. Its restoring ability and agronomic traits were excellent. Its identified resistance to rice blast was grade 3 and bacterial blight grade 1 in field. In the late season of 2014,Yuehui 88 crossed with two-line sterility line Y58S and obtained hybrid rice combination Y Liangyou 88,which was resistant to rice blast and moderately resistant to bacterial blight. Its yield in trial reached 6543 t/ha,increased by 4.97%compared with control Shenliangyou 58 xiangyou-zhan,but the difference was insignificant(P>0.05). The rice quality was identified as national quality grade 3 and provin-cial quality grade 3.ConclusionMAS technology can effectively realize multi-gene polymerization(genes Pi1,Xa23 and Wx),improve resistance of Yuehui 826 to rice blast and bacterial blight and optimize rice quality. Moreover,the new restorer Yuehui 88 is obtained to provide parent materials for quality hybrid combination which are resistant to diseases. Yuehui 88 is soft rice with resistance to rice blast and strong resistance to bacterial blight.