以华201S为受体亲本.以含Xa21和Xa7基因的抗白叶枯病材料华恢20为供体亲本,进行1次杂交、3次回交和3次以上自交,每个世代用基因内标记PTA248对Xa21进行分子检测,用连锁标记STSP3(与Xa7的遗传距离为0.9 cM)对Xa7进行检测.新选育的4个株系YRT009(Xa21)、YR7014(Xa21)、YR7016(Xa7)和YR7023(Xa7/Xa21)在生育期、主要农艺性状、育性转换特性方面都与华201S基本相似.YRT009(Xa21)和YR7014(X021)对PXO61、PXO99、ZHE173和GD1358等4个菌株具有良好的抗性,而对FuJ和YN24不具有抗性.YR7016(Xa7)和YR7023(Xa7/Xa21)对6个菌株都表现良好的抗性,尤其足聚合双基因的YR7023(Xa7/Xa21)对6个菌株都表现高抗.表明已经将广谱白叶枯病抗性基因Xa21和Xa7渗入到华201S中,成功地改良了华201S的白叶枯病抗性.%Hua 201S is an elite photo-thermo-sensitive genie male sterile(PTGMS) line, which was used for developing two-line hybrid rice. A bacterial blight resistant breeding line ‘ Huahui 20’ containing Xa21 and Xa7 genes as donor parent was crossed with Hua 201S. F1 was backcrossed to Hua 201S for three times. The BC3Fi progenies were advanced to BC3 F3 by selfing.The primers PTA248 for Xa21 and STSP3 (genetic distance to Xa7 is 0. 9 cM) for Xa7 were used for molecular markerassisted selection in each progeny. The fertility alterations, main agronomic traits and growth durations of the four selected lines YR7009(Xa21 ), YR7014 ( Xa21 ), YR7016 (Xa7) and YR7023 ( Xa7/Xa21 ) were similar to the recipient parent Hua 201S. YR7009(Xa21 ) and YR7014(Xa21 ) were resistant against four Xanthomonas oryzae pv. oryzae(Xoo) strains, PXO61,PXO99, ZHE173 and GD1358, but not resistant against two Chinese strains, FuJ and YN24. YR7016(Xa7) and YR7023 (Xa7/Xa21) were resistant against all the six Xoo strains tested. It showed that Xa21 and Xa7 were introgressed into the PTGMS line Hua 201S, improving the resistance against rice bacterial blight.
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