Improvement Of The Bacterial Blight And Insect Of Three Restorer Lines

Rice bacterial blight (BB) stem borers (leaffolder, Chilo suppressalis, tryporyza incertulas) can threaten the rice yield stability and reduce the rice quality. Most of popularized hybrid rice varieties in China were susceptible to BB and stem borer. The molecular marker assisted selection (MAS) and backcross are an effective technological method to introgressing resistance genes into elite popularized varieties for developing new promising varieties with resistances to diseases and insects.Three bacterial blight resistance genes Xa7, Xa21, Xa23and one insect-resistance gene cry1C*were introgressed into three rice restorer lines, Yihuil577, Zhehui7954and Minghui1259, by using MAS and backcrossing in this study. After several breeding lines harboring single R-gene were developed, the gene pyramiding methods were used for developing breeding lines bearing multi-resistance genes. The performances of resistance, yield, growth duration, main agronomic traits and rice quality in developed breeding lines and their hybrids were evaluated at experiment farm of Huazhong Agricultural University, Wuhan. The main results are showed as follows:1. Xa7, Xa21, Xa23and cry1C*were introgressed into Yihui1577, Zhehui954and Minghui1259by MAS and backcrossing, respectively.58breeding lines harboring different R-genes were selected, including six lines harboring Xa7, Xa23, Xa7+Xa23, cry1C*Xa7+cry1C*, Xa23+cry1C*, Xa7+Xa23+cry1C*,four lines Xa21, Xa7+Xa21, Xa21+cry1C*, Xa7+Xa21+cry1C*,respectively. Several CMS were crossed with these breeding lines.2. Seven strains of Xanthomonas oryzae pv. Oryzae, PXO61, PXO99, ZHE173, GD1358, FuJ, YN24and HeNll were inoculated to58breeding lines and their hybrid combinations. The results showed that breeding lines and hybrid combinations carrying Xa23were resistant to all of seven Xoo strains. The breeding lines and hybrid combinations carrying Xa21gene were resistant to six Xoo strains, PXO61, PXO99, ZHE173, GD1358, YN24and HeNll. The breeding lines and hybrid combinations carrying Xa7gene were resistant against four Xoo strains, PXO61, GD1358, ZHE173and FuJ. The breeding lines and hybrid combinations carrying Xa7and Xa21genes were resistant to seven Xoo strains. The resistance of the breeding lines and hybrid combinations carrying Xa7+Xa23showed the highest level and wide-spectrum of resistance than the other breeding lines and hybrid combinations.3. The results of evaluating the insect-resistance in the field showed that the breeding lines and their derived hybrids carrying cry1C*were not damaged by leaffolder and stem borer.4. Four restorer lines and derived hybrids resistance to BB, one restorer line and derived hybrid resistance to both BB and stem borer were selected, respectively. They can replace Yihui1577and derived hybrids in rice production. HH1208(Xa23), HH1210(Xa7+Xa23), HH1211(Xa7+Xa23) and HH1206(Xa7+Xa21) and derived hybrids in which YixianglA was used as female parent were highly resistant to BB. The evaluation results of yield, main agronomic traits and rice quality traits showed as similar as Yiyihui1577and Yixiang1577. HH1216(Xa23+cry1C*) and Yixiang1A/HH1216were resistant to both BB and stem borer. Four superiority combinations against BB,CS15S/HH1206(Xa7+Xa21), Jingke1A/HH1206(Xa7+Xa21), JufengA/HH1206(Xa7+Xa21) and Chuannong1A/HH1206(Xa7+Xa21)were selected.5. Three restorer lines and derived hybrids resistance to BB, one restorer line and derived hybrid resistance to both BB and stem borer were selected, respectively. They can replace Zhehui7954and derived hybrids in rice production. ZH1001(Xa7), ZH1006(Xa23), ZH1008(Xa7+Xa21) and derived hybrids, Ⅱ-32A/ZH1001(Xa7), Ⅱ-32A/ZH1006(Xa23), Ⅱ-32A/ZH1008(Xa7+Xa21) were resistant to BB. The evaluation results of yields, main agronomic traits and rice quality traits showed as similar as Zhehui7954and Ⅱ-you7954, respectively. ZH1012(Xa7+crylC*) and II-32A/ZH1012(Xa7+cry1C*) were resistant against both BB and stem borer. Their yields, main agronomic traits and rice quality traits were as similar as Zhehui7954and Ⅱ-you7954, respectively. Two superiority combinations against BB, JingkelA/ZH1001(Xa7) and Jingke1A/ZH1006(Xa7+Xa21) were selected.6. One restorer lines and derived hybrids resistance to BB, one restorer line and derived hybrid resistance to both BB and stem borer were selected, respectively. They can replace Minghui1259and derived hybrids in rice production. MH1006(Xa7+Xa23) and its hybrid combination Ⅱ-32A/MH1006(Xa7+Xa23) were resistant to BB. MH1008(Xa7+cry1C*) and Ⅱ-32A/MH1008(Xa7+cry1C*) were resistant to both BB and stem borer. The evaluation results of yield, main agronomic traits and rice quality traits showed as similar as Minghui1259and Ⅱ-youl259.