Molecular Detection and Analysis of Blast Resistance Genes in Rice Main Varieties in Jiangsu Province, China

Rice blast, caused by Pyricularia oryzae, is one of the most destructive rice diseases worldwide. Using resistant rice varieties is the most cost-effective way to control the disease, and it is crucial to analyze the resistance level and the resistance genes distribution of the main varieties. In this study, we collected 119 rice main varieties in Jiangsu province and evaluated the resistance to leaf and panicle blast and found that indica rice was more resistant to rice blast than japonica rice. Moreover, we detected the distribution of 14 resistance genes (R genes) in the 119 varieties. The distribution frequencies of three R genes, Pish, Pit, and Pia, were higher than 80%, and the Pigm had the lowest distribution frequency (1.68%), followed by Pi2 (15.18%) and Pi5, Piz-t (24.37%). Combined with the multiple stepwise regression and the resistance contribution rate, eight major R genes Pita, Pi5, Pi9, Pib, Pb1, Pikm, Piz-t, and Pi2 significantly affected the resistance of rice, and we also found that six gene combinations with 100% resistance contribution rate could effectively increase the resistance of rice varieties. In summary, monitoring the resistance level of rice varieties and analyzing their resistance genes were beneficial for rice resistance breeding.