| Rice(Oryza sativa)is one of the world’s major food crops,provide the main energy source for nearly 50% of the world population.China’s rice production ranks first in the world,Heilongjiang Province is an important japonica rice producing areas,rice blast is to limit the high yield of rice in Heilongjiang Province,one of the important biological stress factors.To maintain high yield and stable rice production,breeding and rational use of resistant varieties is the most effective way to control rice blast.To this end,we carry out genetic testing resistance and resistance evaluation contained major rice varieties in Heilongjiang Province,theoretical guidance for the rational use of existing breeding resistant varieties and new varieties.In this study,the resistance genes Pita,Pia and Piz-t were tested in 48 rice cultivars from Heilongjiang Province,and the resistance of 23 rice cultivars was evaluated by inoculation.The results of the trial study are as follows:In this study,we used the rice disease resistance gene sequence in the Gen Bank database on NCBI website,The Pita,Pia and Piz-t resistance gene primers were designed to be 4 pairs,1 pair and 3 pairs,respectively,Pita genes respectively contained IRBLzt-7,IRBLa-A gene containing Pia IRBLta-K1 and Piz-t genes containing as a positive control,A specific fragment was obtained by PCR amplification with negative control of LTH without resistance gene.The four specific fragments of Pita gene were 1069 bp,1873bp,51 bp and 571 bp,the specific fragment of Pia gene was 2196 bp,and the three specific fragments of Piz-t gene were 206 bp,3154bp and 136 bp,respectively.8 pairs of specific primers were used to carry out PCR amplification of 48 rice cultivars in Heilongjiang Province,Beidao 3,and other 27 varieties containing Pita,Pia and Piz-t genes,representing 56.25% of the species tested;Daohuaxiang 2 and other 8 varieties containing pita and pia gene,accounting for 16.67% of the tested varieties;Beidao 4,and other 10 varieties containing Pia and Piz-t gene,accounting for 20.83% of the species tested;Kongyu 131 and other 3 varieties containing only Pia gene,accounting for 6.25% of the tested varieties.It can be seen that the Pia,Piz-t and Pita genes are more widespread in the main rice cultivars in Heilongjiang Province.The varieties carrying Pia,Piz-t and Pita genes account for 100%,77.08% and 72.92%.In the field of these three genes also play some role in disease resistance,but the higher the number the more resistant gene which does not contain frequency resistance,resistance genes which may contain other varieties.Measuring the frequency of resistance 23 Heilongjiang major rice varieties in five major areas 180 rice blast fungus strains indoor inoculation the seedlings,The results show that:The total resistance of the 23 main cultivars to the tested strains was strong,but the resistance among the cultivars was quite different.Longjing 42 and other 11 varieties of resistance frequency of 81.1% or more,showing resistance;Longqingdao 3 and other 11 varieties of resistance frequency between 60% to 80%,showing moderate resistance;The frequency of resistance of Longjing 21 was 56.2%,which showed moderate susceptibility.The results showed that there were significant differences in the resistance of the cultivars to the blast fungi strains in different rice regions in Heilongjiang Province.The varieties of resistance to the pathogens of Suihua,Daqing,Qiqihar,Luobei and Harbin rice cultivars were respectively 34.8%,30.4%,78.3%,95.6% and 95.6% respectively.The RAC values of seven combinations,such as Longjing 42 and Longjing 40,were higher,indicating that the combined disease resistance was strong and the disease was effective. |
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