Identification Of Pi9 Gene Among Rice Cultivar In Heilongjiang Province And Improvement Of Rice Blast Resistance For Daohuaxiang

Rice plays an important role in the world’s food production,it’s a pivotal crop in the world.The rice blast harms the rice seriously,it endanger the rice from yield and quality.All along,rice blast is the question of questions in rice diseases because of it’s wide range,variation speed and serious damage.Regard the existing rice resources as a starting point, then screening and promoting excellent resistance resources is always the first choice in rice blast resistance breeding. Use molecular marker technology to screen excellent cultivars could get resistance resources quickly and effenciency. Pi9 is one of the widest genetic resistance spectrum among the cloned rice blast resistance genes, it could resist infection of physiological races from many countries and regions in the state effectively.At the same time, the gene is valuable of application in Heilongjiang Province.This study used the p B8 marker which is closely linked with Pi9 gene, to screen rice blast resistance varieties among 96 major cultivars in Heilongjiang Province, at the same time, inculate the material in both seeding stage and tillering stage, to evaluate the resistance of each cultivar.After clearing distrubitiong of Pi9 gene in 96 Heilongjiang province’s major cultivar, use 75-1-127 as the donor parent which include monogenic lines of Pi9 gene, High quality japonica Daohuaxiang as recipient parent for crossbreeding,use p B8 as maker for molecular marker selection in hybridized group F2 generation,at the same time,identify the rice blast resistance at seeding stage and tilling stage by dominant rice blast race-ZA5 for the F2 generation group,and detect the agronomic characters such as ripening rate,thousand seed weight and so on for the inoculated plants.Choose the single plant which carries Pi9 gene and whoes ability of resistance improved successfully and agronomic characters is choiceness.The experiment got the following main results:(1)Among the 96 selected major rice varieties in heilongjiang province, a total of 44 cultivars carry Pi9 gene, is 45% of the selected cultivars.Studying the distribution of Pi9 gene has an important significance for breeding of rice blast resistance in Heilongjiang Province.(2)Inoculation identification test for the selected 96 major cultivars showed that disease levels of the 44 cultivars carrying Pi9 gene are all lower than the 4th grade, it shows resistance for the rice blast overall.Disease levels of 52 cultivars without Pi9 gene are all higher than the 5th garde, it shows infected overall. Pi9 genes is high value in breeding for rice disease resistance of Heilongjiang Province.(3)Among 113 per plant of hybridization F2 generation of Daohuaxiang and 75-1-127, Pi9 gene imported into 105 plants successfully, only 8 individuals excluded Pi9 genes, To transfer Pi9 gene between cultivars through hybridization will be realiztic.Finally,6 units was found whose resistance for rice blast and characters are both choiceness through the experiment for agronomic and quality.(4)Among the F2 generation of Daohuaxiang and 75-1-127 hybridization, compared with the strains without Pi9 gene,everage disease level of strains carrying Pi9 genes is 3 grade lower. Use Pi9 gene to improve the resistance for rice blast among good-quality rice cultivars is feasible.