Development Of Restorer Lines And Male Sterile Lines For Two-line Hybrid Rice With Multiple Resistances

Rice borers,brown planthopper?BPH?,blast and bacterial blight?BB?are the most destructive diseases and insect pests in rice production.The occurrence of these diseases and insect pests will reduce the commercial value,such as yield decreases and quality decreases.9311 is an excellent restorer line widely used in two-line and three-line hybrid rice in southern China,but 9311 is susceptible to blast,borers,BPH and BB.Studies have shown that the most economical and effective method is to select resistant varieties by using resistance genes to pests and diseases.In this study,the R-genes Cry1C*,Pi9,Xa23,Bph14,Bph15 were pyramided to develop multi-resistance rice breeding lines by using developed lines Huakang3005,Huakang3037 and Huakang3038 with the genetic background of 9311 through hybridization and molecular marker-assisted selection?MAS?.I also developed several thermo-period-sensitive genic male sterile?PTGMS?lines harboring Cry1C*,Pi2,Bph14,Bph15,Xa23 from the offspring between Hua1306S and DB1503-88-7 which developed in our laboratory.These developed lines with multiple resistance will be used as basic breeding materials for developing two-line hybrid rice varieties with multi-resistance.Here are the results of the study:1.Twelve new restorer lines were obtained,carrying Cry1C*,Bph14,Bph15,Xa23and Pi9 genes,developed from the offspring of‘Huakang3005/Huakang3037//Huakang3005/Huakang3038'.These twelve developed lines were coded as TMQ15110-11-280-5-1,TMQ15110-11-39-2,TMQ15110-14-180-1,TMQ15110-14-229-1,TMQ15110-14-230-8,TMQ15110-8-191-14-8,TMQ15110-11-95-8,TMQ15110-11-96-10,TMQ15110-11-113-3,TMQ15110-11-214-9,TMQ15110-14-241-10 and TMQ15110-40-49-4?2.The twelve new developed restorer lines were not damaged from rice borers in the field without controlling borers during the whole growth period,but the 9311 with nonresistance gene was harmed by rice bores.Identification of resistance to BPH and BB showed that twelve new lines showed resistance or highly resistance to BPH,and twelve new lines also showed resistance or highly resistance to GD1358 and ZHE173 of Xoo strains.Due to the limitation of conditions,the identification of rice blast resistance was not done.3.In hybrid combinations,as long as one of the parents carries Cry1C*gene,hybrid F₁s were resistant to rice borer,implying the resistance of Cry1C*gene to borers is completely dominant.Only when both parents carry Bph14 and Bph15 genes,F₁ hybrid can showed resistance to BPH,implying that Bph14 and Bph15 genes are non-dominant.As long as one of the parents carries Xa23 gene,the hybrid F₁s showed resistance to BB.Although the lesion length of the hybrid F₁ was slightly longer than that of the homozygous parent,implying the gene Xa23 is dominant.4.The results of yield test showed that the yield of new lines of multi-resistant restorer lines was slightly increased compared with that of 9311,The yield of some individual lines was significantly increased,and the growth period was 1-4 days shorter than that of 9311.However,the rice quality of most lines was worse than that of 9311.Combining ability analysis showed that the yield and general combining ability of main agronomic traits of new restorer lines with multi-resistance genes were similar to those of9311.5.In the offsprings of‘DB1503-88-7/Hua1306S',we selected four Photo-thermo-sensitive genic male sterile?PTGMS?lines,one line carries Pi2 and Cry1C*genes,one line carries Pi2,Bph14,Bph15,Cry1C*genes,and two lines carries Xa23,Pi2,Bph14,Bph15,Cry1C*genes.