Race-Specific Partial Resistance to Blast in Temperate Japonica Rice Cultivars

Abstract

Twenty-nine of 53 japonica rice cultivars and breeding lines tested for resistance to blast disease in nursery trials in Korea and the Philippines showed complete resistance at one or both locations. Seventeen of 24 entries that tested qualitatively susceptible at both locations showed slower disease progress in the Philippines. Greenhouse tests using japonica cultivars Daechang, Nagdong, and Palgeum, and a susceptible check indicated that Korean isolates were more aggressive than Philippine isolates on the japonica cultivars; the isolates were equally aggressive on the susceptible check. The results suggest that race-specific partial resistance caused the slow disease progress on japonica rices in the Philippine nursery test.