分子标记辅助改良培矮64S稻瘟病抗性

为提高我国大面积应用的两系光温敏不育系培矮64S的稻瘟抗性,本研究通过杂交转育与分子标记选择相结合的途径,利用RM3330与RM262为标记,将Pi25与Pi-d(t)基因成功聚合于培矮64S中,经抗性、不育性、综合农艺性状评价,获得了5个基因型纯合且农艺性状稳定的F8代抗性改良候选不育系。抗性鉴定结果显示,抗性改良候选不育系及其抗性组合的叶瘟病情指数平均降幅为18.78%和23.24%,穗颈瘟病情指数平均降幅为18.58%和58.45%,抗性提高幅度极显著。育性观测结果表明抗性改良候选不育系不育度都在99.5%以上,柱头外露降低5.64%,包颈粒率降低8.55%。经济性状调查结果显示不育系除穗粒数下降、有效穗增加外,其余经济性状变化不明显;试配的杂交组合平均理论产量和实际产量比对照提高16.22%和6.89%,增产极显著。这些结果表明,通过Pi25与Pi-d(t)基因的导入显著提高了培矮64S稻瘟病抗性,获得了实用的光温敏不育系新材料。

Improving the Blast Resistance of Pei-ai-64S by Marker-assisted Selection

Two-line photo-thermal-sensitive male sterile Pei-ai-64S is widely planted in China.In order to improve its blast resistance,using RM3330 and RM262 as markers,Pi25 gene and Pi-d(t) gene were transferred together in Pei-ai-64S through combining the cross breeding and the marker assisted selection.Five homozygous male sterile lines,which are the F8 generation,were screened out through assessing the blast resistance,the sterility and the agronomic traits.Their blast resistances have been improved and their agronomic traits are steady.The identification of blast resistance shows that the disease indexes of leaf blast in resistance improved male sterile lines and in the hybrids derived from these lines averagely decreased 18.78% and 23.24% respectively,and the disease indexes of neck blast averagely decreased 18.58% and 58.45% respectively.The blast resistance is significantly improved.The detection of fertility shows that the sterile degrees of that improved lines are all above 99.5%,and the stigma exsertion rate decreased 5.64%,and the unemerged spikelet rate decreased 8.55%.Furthermore,except the grain number per spike decreasing and the number of effective spikes per plant increasing,other economic traits have no significant change.Comparing with the control,the average theoretical yield per plant and the yields of plots of the hybrids increased 16.22% and 6.89% respectively.The yield increased significantly.These results show that the blast resistance of Pei-ai-64S could be significantly improved by introducing Pi25 and Pi-d(t) into it,and this new photo-thermal-sensitive male sterile line is practical.