Evaluation of rice germplasm for resistance to Gerlachia oryzae

Abstract

Two hundred exotic and land races including improved rice cultivars were screened in the greenhouse for resistance to leaf scald caused by Gerlachia oryzae. Artificial inoculations were made on the leaves with mycelial discs of the fungus from culture médium on leaves of 30-day old plants raised in trays. The degree of resistance or susceptibility was based on disease severity determined using lesion extension. Among the land races, the cultivars Rexoro, Três Potes, Baixada and Prata Preto were resistant. Some of the rice blast resistant sources such as cvs. Colombia-1, COL-14 were also resistant to leaf scald. The improved cultivars Araguaia and Cuiabana exhibited higher degree of susceptibihty compared to cvs. Guarani, Centro-America and Cabaçu.