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.

First report of Pyricularia oryzae the cause of blast disease in upland rice, in Lombok, West Nusa Tenggara

“…Morphologically, the most typical characteristics of blast disease shown in dryland rice crops are brown spots shaped like rhombuses (Figure 1). Kuswinanti et al (2023) also obtained the same symptom characteristics in Pyryicularia orizae. Other studies also report on the blast disease Pyricularia oryzae, which can attack all rice plant tissues, including leaves, stems, panicles, and grains (Asibi et al 2019), as shown in Figure 1.…”

“…Blast disease potentially attacks every part of rice organs in the fields (Muimba-Kankolongo 2018). Kuswinanti et al (2023) reported the highest percentage of blast disease attacks in Indonesia found on rice leaves, starting from 5% in the first week and reaching 82.1% at the harvest period. Potential yield losses due to blast disease can reach 50% or more, as reported by Nalley et al (2016), following the next survey in 2021, a field survey conducted in two districts on Lombok Island, including Central Lombok Regency, attacked by blast disease at 70% and North Lombok Regency at 20%.…”

“…Blast disease is one of the pests causing Indonesia's rice production decline (Kuswinanti et al 2023). A high-intensity attack by blast disease on rice crops resulted in farmers' losses (Nalley et al 2016;Simkhada and Thapa 2022).…”