Improvement Of The Bacterial Blight Resistance Of Rice Restorer Line Hr15and Insect-Resistance Of Rice Restorer Line Guanghui998

Rice bacterial blight (BB) is one of the three major diseases in rice production on the world, it can threaten the rice yield stability and quality. Stemborers (leaffolders, Chilo suppressalis, tryporyza incertulas) are a group of Lepidopteran insects that cause severe damage to rice production in China, there is an estimate that50million acres are infested with this kind of pest, and the economic losses caused by these insects could account for billions of yuan in2011. The incorporation of resistance genes into cultivars by transgenic method and molecular marker-assisted selection (MAS) technology are the most effective methods for improving the disease and insects resistances in crop genetics and breeding in recent years.The study introgressed BB resistance gene Xa23into restorer line HR15, and introgress lepidopteran insects resistance gene cry1C*into restorer line Guanghui998by using MAS method in the process of the conventional cross-backcrossing. Main research results are as follows:1. The BB resistance gene Xa23was introgressed into the CMS restorer line HR15through molecular-marker assisted backcross selection methods. Ten new breeding lines with BB resistance gene Xa23were selected and crossed with three CMS lines.Seven Xoo strains (PXO61, PXO99, ZHE173, GD1358, FuJ, HeNll and YN24), were used for identifying BB resistance of ten selected lines and recipient and donor parents under the field condition. The results showed that the new selected lines carrying Xa23were highly resistance against BB as similar as donor parent CBB23. Most of F1combinations were also resistance against BB.2. The comparative analysis results of agronomic traits and grain quality between the selected lines and recipient parent (HR15) showed that most of agronomic traits and grain quality charcateristics were similar to HR15. All of agronomic traits of line XFQ10004-4and corresponding combination, BO-ⅡA/XFQ10004-4were as similar as HR15except of higher yield because of BB resistance. The line XFQ10004-4was designed as Huahui23and the corresponding combination designed as BO-Ⅱ-You23which will be applicated for reginal trial in Hainan Province as an alternative to BO-Ⅱ-You15. 3. The insect-resistance gene cry1C*from transgenic line T1c-19was introgressed into Guanghui998, an elite CMS restorer line, and four new restorer lines carrying cry1C*were selected and crossed with five CMS lines. The results of investigating under the field conditions without pesticide-applying showed that the selected four restorer lines and their F1hybrids showed high resistance against leafforder. The results of Bt protein assessment showed that Bt proteins of four new restorer lines and their hybrids were expressed as similar as donor parent T1c-19.4. The results of agronomic traits analysis and grain quality analysis showed that the main agronomic traits and the grain quality of improved lines were similar to original Guanghui998. All of the agronomic traits of four new lines, XFQ10072-5and XFQ10072-33were better than Guanghui998, but their grain qualities has not changaned for better. The yield heterosis of JufengA/XFQ10072-33was seemed to be the best among tested hybrids.