三个中籼稻骨干恢复系对白叶枯病和褐飞虱抗性改良效果的评价

利用分子标记辅助选择和田间鉴定选择相结合的方法，将抗白叶枯病基因Xa23和抗褐飞虱基因Bph18(t)导入明恢86、蜀恢527和浙恢7954等3个骨干中籼恢复系，获得带有Xa23抗性基因纯合的改良恢复系明恢86-Xa23、蜀恢527-Xa23、浙恢7954-Xa23和携有抗褐飞虱Bph18(t)基因的蜀恢527-Bph18(t)、浙恢7954-Bph18(t)，并从蜀恢527/IRBB23 F₁和浙恢7954/IR65482 F₁复交后代中选育出的带有Xa23和Bph18(t)的双基因聚合系浙蜀-Xa23-Bph18(t)。明恢86-Xa23、蜀恢527-Xa23、浙恢7954-Xa23和浙蜀-Xa23-Bph18(t)对中国和菲律宾的17个白叶枯病菌均表现高抗，蜀恢527-Bph18(t)、浙恢7954-Bph18(t)和浙蜀-Xa23-Bph18(t)对褐飞虱的抗性也达到中抗以上水平。抗性改良恢复系及其与不育系II-32A、沪旱11A的测交种在不接种白叶枯病菌条件下的产量和结实率与原来的恢复系及相应杂交种相仿，但在接种条件下带有Xa23基因的恢复系及测交种的结实率和产量明显优于原来的恢复系及相应杂交种。研究表明，抗性基因Xa23在不同恢复系背景下的抗性表达完全，对恢复系白叶枯病改良的效果明显，而抗性基因Bph18(t)对褐飞虱的改良效果与遗传背景有关。对分子标记回交和复交改良恢复系的抗病虫性进行了讨论。

Evaluation on Effect of Resistance Improvement of Bacterial Leaf Blight and Brown Planthopper for Three Dominant Indica Restorer Lines

A novel bacterial blight (BB) resistance gene, Xa23, and brown planthopper (BPH) resistance gene, Bph18(t) were introgressed into three popular restorer lines (Minghui 86, Shuhui 527, and Zhehui 7954) for wild abortive cytoplasmic male sterility by marker-assisted backcross and pyramiding breeding approaches in combination with artificial inoculation and stringent phenotypic selections. The four derived BB resistant restorer lines Minghui 86-Xa23, Shuhui 527-Xa23, Zhehui 7954-Xa23,and Zheshu-Xa23-Bph18(t)] and their derived hybrid combinations with II-32A and Huhan11A demonstrated similar BB resistance spectrum as the donor parent, IRBB23. The three derived BPH resistant restorer lines Shu 527-Bph18(t), Zhehui 7954-Bph18(t), and Zheshu-Xa23-Bph18(t)] showed resistant or moderate resistant to BPH. The newly developed BB and BPH resistant restorers and their derived hybrids were identical to their respective original versions for agronomic traits especially under disease free condition. However, under severe disease condition, the four BB resistant restorer lines exhibited significantly higher grain weight and spikelet fertility as compared to the respective original restorer lines thus further resulting in BB resistant hybrids with significantly higher grain yields than their respective original hybrids. The results indicated that the Xa23 gene could completely express its dominant resistance in different backgrounds of both restorer and male sterile lines across different growth stages, suggesting its immense breeding value in BB resistance improvement for hybrid rice. However, effect of resistant improvement of Bph18(t) for BPH depends on genetic background. Improvement of resistance of BB and BPH for restorer lines by molecular marker-assisted backcross and pyramiding was deeply discussed.