Analyzing Avirulence Genes Of Magnaporthe Oryzae From Heilongjiang Province And Screening Of Rice Germplasm Resistance To Blast Fungus

Rice blast, caused by Magnaporthe grisea, is one of the most constraints to rice productionworldwide. In this study, a total of177single spore isolates, collected from different rice main cultivarsin the different growing regions of Heilongjiang in2009, were used to test the Avr genes by the specificprimers of Avr1-co39, Avr-pita, ACE1, Avr-pik, Avr-pizt, Avr-pia and Avr-pit, and20rice varieties withsingle blast resistance gene were inoculated in the greenhouse to analyse the isolates’ virulence.Moreover, the resistance of23rice cultivars to blast were evaluated by inoculation at the seedling stage.The main results are described as follows:1. PCR results showed that all the7Avr genes were widely distributed in the isolates fromHeilongjiang province. Among them, ACE1and Avr1-co39had the highest and lowest frequencies with61.6%and31.6%, respectively. The frequencies of the other Avr genes varied from42.6%to55.9%,indicating that distributions of Avr genes in the isolates were associated with geographic locations andrice varietes in Heilongjiang.2. Pi-9showed the broadest resistance spectrum (80%~100%) to the isolates collected from6ricegrowing regions in Heilongjiang province, having the extensive utilization value in rice breedingprogram. The resistance spectrum of Pi-2(t)、Pi-zt、Pi-5(t) and Pi-12(t) ranged from50to70%, alsoshowed higher utilization value.3. Gayabyeo, Huayu560, Gang46B, Co43, X21and Pokhreli had resistance to the isolates of blastpathogen from Heilongjiang at the seedling stage. The specific fragment of Pi5was detected in Pokhreli,and specific fragments of Pi-zt and Pita were detected in Huayu560. Pi9didn’t be detected in the sixrice varieties.In conclusion, our results will provide useful information for rice breeding in Heilongjiang province.