分子标记辅助选择改良水稻恢复系香5的病虫抗性

香5是由湖北省农科院选育的优质两系杂交稻恢复系,所配组合广两优5号(广占63-4S/香5)于2013年通过了湖北省审定.利用回交和分子标记辅助选择技术,将供体亲本MD12086-1351中的抗稻瘟病基因Pi9、抗褐飞虱基因Bph14、Bph15和抗白叶枯病基因Xa23渗入到香5背景中,育成了3个同时携带Pi9、Bph14、Bph15和Xa23基因的新株系.鉴定结果表明,新株系的叶瘟抗性明显提高,穗颈瘟抗性部分提高,苗期抗褐飞虱,分蘖盛期高抗白叶枯病;产量、主要农艺性状、香味和稻米品质主要指标与香5相似.新株系所配的组合在产量、主要农艺性状上与香5所配的组合相似.表明新株系可以作为香5的替代系用于培育抗稻瘟病、抗褐飞虱和抗白叶枯病的两系杂交稻新组合.

Improvement of Disease and Insect Pest Resistance of Rice Restorer Line Xiang 5 by Molecular Marker-assisted Selection

Xiang 5 is a high quality restorer line of two-line hybrid rice developed by Hubei Academy of Agricultural Sciences,and the derived combination Guangliangyou 5(Guangzhan 63-4S/Xiang 5)was certificated by Hubei Province in 2013.In this study,the blast resistance gene Pi9,the brown planthopper(BPH)resistance genes Bph14 and Bph15 and the bacterial blight(BB)resistance gene Xa23 were simultaneously introgressed into the genetic background of Xiang 5 through molecular marker-assisted backcrossing by using MD12086-1351 as donor parent.Three selected breeding lines designated as STQ15035-53-139-10-10,STQ15035-53-97 and STQ15035-53-176 carrying homozygous Pi9,Bph14,Bph15 and Xa23 were developed.The results of BPH and BB resistance evaluation showed that the improved lines were resistant to BPH and BB while Xiang 5(the recipient)was highly susceptible.The resistance spectrum identification of rice leaf blast showed that the resistance frequency of the three improved lines ranged from 90.91%to 95.45%,while Xiang 5 was only 27.27%.The evaluation results under natural blast epidemic field conditions showed that three improved lines conferred significantly increased resistance level of leaf blast compared with Xiang 5,but there was only a small improvement for panicle neck blast.The aroma,main agronomic traits and grain quality of the improved lines were similar to those of the recipient parent Xiang 5,and the hybrids derived from the improved lines were also similar to those of Xiang 5 in main agronomic traits and grain yield,indicating that the improved lines can replace Xiang 5 for developing new two-line hybrids with resistance to blast,BB and BPH.