| Rice is the most important food and crop of China as the main stable food of one third people in the world. Rice blast causes the worst devastating effects among the three main diseases of rice, which makes much loss to economic production and food supply. One subjective of this research is to improve the resistance of photoperiod and thermo-period sensitive genic male sterile PA64S by pyramiding the blast resistance genes Pi-1 and Pi-2 from sponsor BL6 through molecular marker-assisted selection. We obtain the BC3F1 by three times backcross between BL4 and PA64S, and then 43 positive material lines after self.10 lines with highly sterile and resistance to blast among the 43 were chosen and planted in Wuhan and Yuan'an to investigate pollen sterility from July to September everyday, and treated by long day light(14h) and low temperature(23.5℃) in phytotron.10 improved PA64S lines and 43 hybridizing with 9311 were planted in Yuan'an by natural induction in field to investigate the resistance to leaf blast and neck blast. The results are as follows:1. The 10 improved PA64S lines were selected from the 43 positive materials, and 5 of them showed sterility degree above 99.5% in natural field in Wuhan in August in 2009.8 of the 10 improved lines in Yuan'an showed a pollen sterility above 99.5%. Under the condition of phytotron,3 ot the 10 improved lines had a complete pollen sterility above 99.5%.2. The investigation of the 10 improved lines showed a moderate resistance to leaf blast and a strong resistance to neck blast, which had significant difference from PA64S. The results of the resistance to leaf blast and neck blast showed a significant correlation. The hybrid lines of 43 positive lines and 9311 represents a strong resistance to leaf blast at seedling, but fluctuated at heading stage from 1.6 to 3.1, meanwhile, the resistance of the hybrid lines to neck blast at head was high and significant correlated with the resistance to leaf blast at head stage.A genetic linkage map was constructed through a RIL group of erbaiyin/ZS97.5 QTLs for leaf blast resistance and 2 QTLs for neck blast resistance were detected, which existed on chromosome 1,6 and 11. Additive effect of QTLs for leaf blast resistance are between 0.1925 and 0.4031, and phenotype contribution of which is between 7.86% and 39.86%; Additive effect of QTLs for neck blast resistance are negative, and phenotype contribution of which is between 9.73% and 24.07%. |
