Effects of Adult-Plant Resistance on Blast Severity and Yield of Rice. Byung Kook Hwang, Professor, Department of Plant Protection, Korea University, Seoul, Korea. Young Jin Koh, and Hoo Sup Chung. Professor, Department of Agricultural Sciences, Suncheon National University, Suncheon, Korea; and Professor, Department of Agricultural Biology, Seoul National University, Suweon, Korea. Plant Dis. 71:1035-1038. Accepted for publication 24 May 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-1035.

Adult-plant resistance is defined as resistance that is expressed as the plant matures. Field studies were performed in flooded plots in 1984 and 1985 to evaluate various degrees of adult-plant resistance to leaf and panicle blast and to determine the relationship of such resistance to rice yield. The rice cultivars showing adult-plant resistance to leaf blast were effectively protected from leaf blast under flooded conditions. Cultivars with high quantitative levels of adult-plant resistance to leaf blast showed higher resistance to both leaf and panicle blast. Reduction of yield by blast was less in the adult-plant-resistant cultivars than in susceptible cultivars. The cultivar Dobong, which was highly resistant to both leaf and panicle blast, showed as stable a yield potential as Nongbaek, which has a hypersensitive type of resistance to blast.

Keyword(s): Pyricularia oryzae.