Analysis of Rapid increase of Rice Blast Fungus Race KI-409 in Korea

한국 도열병균 KI-409 race의 급격한 증가 현황과 원인 분석

Temporal and spatial distribution of Korean rice blast fungus (Pyricularia grisea) race KI-409 that has been rapidely increased since 1993 and became predominant in 1995 in Korea were investigated. Varietal resistance of current commercial cultivars of rice to the race was also tested in this study. The race KI-409 was first isolated from rice cv. Namyangbyeo in 1985. Since 1985 the race had been isolated mainly from the rice cultivars having BL1 BL7 pedigree as a resistance source. Distribution ratio of the race in 1995 was 23.7% in average and became a predominant in the P. grisea population in Korea. The race distributed widely and found in all the eight provinces in Korea. Many commercial cultivars such as Chucheongbyeo as well as those with BL1 or BL7 as a genetic background were found to be susceptible to the race KI-409.