Identification of avirulent genes in Magnaporthe oryzae in Hunan province

ObjectiveComposition of avirulent genes types of Magnaporthe oryzae in Hunan province were studied, in order to provide reference basis for breeding of new rice cultivars and rational distribution of blast -resistant cultivars.MethodA total of 120 M. oryzae monadic isolates were isolated from rice susceptible cultivars (Lijiangxintuanheigu, LTH) in Hunan Taojiang nurseries in 2014. Then, 24 near-isogenic lines (NILs) with known blast-resistance gene was in vitro inoculated artificially with above isolates by acupuncture, and the avirulent genes of tested isolates were identified.ResultThe above 120 M. oryzae isolates all carried 24 avirulent genes, among 24 avirulent genes, occurrence frequencies of Avr-Pita and Avr-Pish were more than 40.00%, while occurrence frequencies of Avr-Piz, Avr-Piz5, Avr-Pi3 and Avr-Pi9 ranged from 30.00% to 40.00%, occurrence frequencies of the rest were lower relatively, especially Avr-Piks, Avr-Pikp, Avr-Pib, Avr-Pi12 and Avr-Pi11 with frequency of less than 10.00%. ConclusionThe rice cultivars carrying resistant genes Pi-ta and Pi-sh sould be generalized in Hunan province; the rice varieties cultivars carrying resistant genes Pi-z, Pi-z5, Pi-3 and Pi-9 should be considered carefully in their utilization and extension in Hunan province; the rice cultivars carrying blast-resistant genes Pi-ks, Pi-kp, Pi-b, Pi-12 and Pi-11 are not suitable for utilization and extension in Hunan province.