基于MAS技术对水稻保持系软华B稻瘟病抗性的分子改良

Molecular Improvement of Rice Blast Resistance in a Rice Maintainer Line Ruanhua B Based on MAS

为选育优质抗稻瘟病保持系软华B,以携带稻瘟病抗性基因Pi46和Pi2的优质籼稻H281作为供体亲本、以软华B为轮回亲本,利用分子标记辅助选择(MAS)技术结合系谱选育法,聚合2个外源基因以改良保持系软华B。对性状稳定的改良株系进行稻瘟病抗性鉴定、稻米品质分析等。通过回交及多代自交,并结合分子标记检测,获得以软华B为遗传背景且含有2个纯合目标基因的BC_(1)F_(6)群体2个、BC_(2)F_(5)群体2个、BC_(3)F_(4)群体2个。田间自然诱发鉴定结果表明,不同回交世代改良材料在自然病圃均抗稻瘟病;育性鉴定结果显示,回交世代对不育系的不育度为52.7%~100.0%;农艺性状考查及米质分析表明,改良株系基本保留了软华B的主要农艺性状和稻米品质特性。SNP基因芯片分析结果显示,BC_(1)F_(6)的背景回复率为74.42%~77.77%,BC_(2)F_(5)的背景回复率为86.42%~87.75%,BC_(3)F_(4)的背景回复率为92.27%~92.59%。利用连续回交、自交和分子标记辅助选择等技术可有效聚合多个抗性基因,获得抗稻瘟病的新保持系,快速实现保持系软华B的分子改良,为选育抗病、优质的杂交稻组合提供良好的亲本材料。

In order to improve blast resistance of the maintainer line Ruanhua B,to carry rice blast resistance genes Pi46 and Pi2 high-quality Indica H281 as the donor parent,Ruanhua B as recurrent parent,using marker-assisted selection(MAS)technology combined with pedigree breeding method,polymerization of two foreign genes with improved maintenance line Ruanhua B resistance,Ruanhua B was carried out on the characteristics of stable strain identification of resistance to rice blast,rice quality analysis,etc.Two BC_(1)F_(6)populations,two BC_(2)F_(5)populations and two BC_(3)F_(4)populations with two homozygous target genes were obtained by backcrossing,multi-generation self-crossing and molecular marker detection.Field naturally induced identification showed that the improved lines of different backcrossing generations were resistant to rice blast.The sterility of backcross generation to sterile lines ranged from 52.7%to 100.0%.Agronomic traits and rice quality analysis showed that the improved lines basically conserved the main agronomic characters and rice quality characteristics of Ruanhua B.The results of SNP gene chip analysis showed that the background response rate of BC_(1)F_(6)was 74.42%—77.77%,that of BC_(2)F_(5)was 86.42%—87.75%,and that of BC_(3)F_(4)was 92.27%—92.59%.Multiple resistance genes can be effectively polymerized by continuous backcross,self-cross and marker-assisted selection techniques to obtain a new maintainer line resistant to rice blast,and achieve rapid molecular improvement of maintainer line Ruanhua B.