分子标记辅助选择Pi9基因改良水稻不育系桃农1A稻瘟病抗性

Improving Blast Resistance of Rice CMS Line Taonong 1A By Pi9-based Marker-assisted Selection Strategy

以籼稻品系75-1-127为广谱持久抗稻瘟病基因Pi9的供体亲本,先后以三系保持系桃农1B及其不育系桃农1A为受体亲本,利用Pi9基因内共显性InDel标记CoInDF_(1)R_(2)开展MAS回交育种以定向改良桃农1A稻瘟病抗性。分子标记CoInDF_(1)R_(2)在75-1-127基因组中扩增出1条大小为354 bp的条带,而在桃农1B和桃农1A基因组中扩增条带大小约为470 bp。分别以75-1-127与CO39作为抗病对照与感病对照进行室内人工接种,得到桃农1A、桃农1B及其改良不育系和保持系的抗菌谱,结果显示,75-1-127的抗性频率为86.67%,桃农1A与桃农1B的抗性频率均为6.67%,而改良不育系桃农1A-Pi9及其保持系桃农1B-Pi9的抗性频率同75-1-127,且田间病圃表现高抗苗瘟。经田间不育特性、农艺性状与产量结构调查分析,育成1个高抗稻瘟病、不育性彻底且稳定、柱头外露率高、包颈粒率低、农艺产量性状优良的新不育系桃农1A-Pi9-1及其配套保持系桃农1B-Pi9-1,实现了桃农1A稻瘟病抗性的定向改良。

To improve blast resistance of the rice cytoplasmic male sterile(CMS)line Taonong 1A and its maintainer Taonong 1B,a PCR-based co-dominant InDel marker,CoInDF_(1)R_(2),was developed according to the sequence information of the broad-spectrum and durable blast resistance gene Pi9,then was used in marker-assisted selection backcross breeding practice.The marker CoInDF_(1)R_(2)amplified a 354 bp DNA band from the genome of 75-1-127,while the PCR product size from both genomes of Taonong 1A and Taonong 1B was about 470 bp.Greenhouse inoculation assay was performed using fifteen Magnaporthe oryzae strains isolated from different rice areas at home and abroad,the Pi9 gene donor rice line 75-1-127 was showed much higher resistance frequency(86.67%)than that of two acceptor parents Taonong 1A and Taonong 1B(6.67%),the improved Taonong 1A-Pi9 and Taonong 1B-Pi9 was showed the same resistance frequency as 75-1-127 and with high-level seedling blast resistance in field nursery.By means of integrated field assays,an improved CMS line Taonong 1A-Pi9-1 and its maintainer Taonong 1B-Pi9-1 were screened,with high-level and broad-spectrum blast resistance,complete and stable sterility,high stigma exsertion rate,low enclosed spikelet rate,excellent a-gronomic and yield traits.