利用分子标记辅助选择改良温敏核不育系GD-8S的稻瘟病抗性

以含有广谱稻瘟病抗性基因Pi 1的籼稻材料BL122为供体，优质感病温敏核不育系GD 8S为受体，通过杂交、多次回交和自交结合分子标记辅助选择技术，将Pi 1基因导入GD 8S中。综合目标基因的分子检测、育性镜检、田间农艺性状表现以及遗传背景的回复率，筛选获得5个改良株系RGD8S 1、RGD8S 2、RGD8S 3、RGD8S 4和RGD8S 5。采用广东省具有代表性的33个菌株进行人工接种抗性鉴定，5个改良株系的抗性频率为75.76%~100.00%，而对照仅为9.09%。农艺性状分析表明，除剑叶长和每株穗数外，其余性状改良株系与对照无显著差异。这些改良株系可用于进一步测配选育高抗稻瘟病杂交稻新组合。

Improving Blast Resistance of a Thermo-Sensitive Genic Male Sterile Line GD-8S by Molecular Marker-Assisted Selection

The broad-spectrum blast resistance gene Pi-1,from the donor line BL122,was introduced into a thermo-sensitive genic male sterile(TGMS)line GD-8S,which possessed good grain quality but high susceptibility to rice blast,by using backcross breeding and molecular marker-assisted selection.Five elite improved male sterile lines RGD8S-1,RGD8S-2,RGD8S-3,RGD8S-4 and RGD8S-5,were selected based on the results of molecular marker analysis,spikelet sterility,recovery ratio of genetic background and agronomic traits.Thirty-three representative blast isolates collected from Guangdong Province,China were used to inoculate the improved lines and the origin line GD-8S artificially.The resistant frequency of the improved lines ranged from 75.76% to 100.00%,much higher than that of the check GD-8S,which was only 9.09%.On the agronomic characters,there was no significant differences between the improved lines and the check GD-8S except for flag leaf length and panicle number per plant.The improved lines could be used for breeding hybrid rice with high blast resistance.