Population structures of Pyricularia oryzae Cavara in South Sulawesi

Abstract

Blast disease caused by Pyricularia oryzae is one of the major rice diseases affecting rice output in Indonesia causing a 90% reduction in yield. This study aimed to determine the distribution of Pyricularia oryzae virulence pathotypes (races) in several South Sulawesi regencies. The P. oryzae races were determined in the Green House using 7 rice differential varieties: Asahan, Cisokan, IR 64, Krueng Aceh, Cisadane, Cisanggarung, and Kencana Bali. A total of 72 P. oryzae isolates from Maros, Gowa, Bone, and Pinrang Regencies were tested. The IRRI evaluation standard assessed the disease intensity seven days after inoculation. There were a total of 24 race compositions of P. oryzae were discovered based on the reactions of different rice varieties. However, only two races were dominant. Race 001 was dominant among Pinrang and Maros isolates, whereas race 020 was dominant in Bone and Gowa. Based on this result, monitoring of disease severity and the dynamics of P. oryzae population race structures is important for the breeding and rational distribution of resistant rice varieties.