利用分子标记辅助选择聚合Pi-1和fgr基因改良水稻恢复系

Pyramiding Pi-1 and fgr Genes to Improve Rice Restorer Lines by Molecular Marker-assisted Selection

以含有广谱稻瘟病抗性基因Pi-1的籼稻品系BL122为稻瘟病基因的供体,籼稻恢复系香型中间材料XH74为香味基因的供体,三系优良恢复系R290为受体亲本,通过杂交、多次回交、基因聚合和多次自交,并同时利用与Pi-1基因紧密连锁的SSR标记RM144以及香味基因fgr的功能标记GRFM04在不同世代分离群体中进行分子标记辅助选择,最终筛选获得6个双基因纯合的改良株系。利用30个广东代表性稻瘟病菌株接种鉴定,6个改良株系的抗性频率为100%,而对照R290抗性频率仅为66.67%;自然病圃诱发鉴定6个改良株系,其叶瘟和穗颈瘟均表现高抗。检测表明6个改良株系叶片和米粒均具有较浓的香味。统计分析表明,除1个株系结实率稍低与对照差异显著外,其余改良株系与对照相比,在所有农艺性状上均差异不显著。通过分子标记辅助选择将稻瘟病基因Pi-1和香味基因fgr聚合到恢复系R290中,不仅显著地提高了恢复系的稻瘟病抗性,而且稻米有了较浓的香味,利用这批改良株系育成杂交稻新组合荣优633和五优633已参加省区试。

To improve blast resistance and grain quality of rice restorer lines by molecular marker-assisted selection is the main objective of this research.In this study,BL122 and XH74,which contained blast resistance gene Pi-1 and recessive fragrance gene fgr,respectively,were used as the donors,and the elite restorer line R290 as the recipient.Then crossing,backcrossing,gene pyramiding and selfing were accomplished according to the breeding procedure.Molecular marker analysis was conducted by using the markers RM144 and GRFM04,which were tightly linked with the Pi-1and fgr,respectively,in different segregating populations.Six improved lines with homozygous genotype in two loci were successfully developed through molecular marker-assisted selection.The frequency of resistance to the pathogens for all improved restorer lines was 100%,higher than that of the check R290,which was only 66.67%,by artificially inoculating 30 representative blast isolates collected in Guangdong Province.The improved restorer lines also displayed high resistance to leaf and neck blast while grown in the epidemic areas.Both leaves and grains of the improved restorer lines showed strong fragrance.Moreover,the results showed that,there was no statistically significant difference in the agronomic traits between the improved lines and the original R290,except for one line,which had significant difference in seed setting rate.The introduction of the blast resistance gene Pi-1 and the recessive fragrance gene fgr into the restorer line by molecular marker-assisted selection improved not only its resistance to blast,but also its grain quality.And two hybrid rice combinations were developed by using these improved lines.