Reaction of gene differential rice varieties against gall midge Orseolia oryzae (Wood-Mason) biotypes in the greenhouse

Abstract

The Asian rice gall midge, Orseolia oryzae (WoodMason) is a serious pest of rice in India. This pest has been contained during the last three decades through cultivation of over 50 high yielding resistant rice varieties suited to different pest endemic areas within the country [1]. However, extensive cultivation of a single variety with one major gene for resistance over a large area resulted in rapid development of virulent biotypes capable of overcoming host-plant resistance. A reoriented breeding strategy to counter the situation involves development of gene pyramids with two or more resistance genes in a single cultivar through marker aided selection approach. So far, ten gall midge resistance genes have been identified and designated [1-3]. However, the reaction of different gall midge biotypes against these specific genes is not completely known. This ·information is essential to make an informed choice of genes for pyramiding in a single cultivar to confer durable gall midge resistance. Hence, the differential rice varieties with known genes against gall midge biotypes 1, 3 and 4 were screened under greenhouse conditions at the Directorate of Rice Research (ORR), Hyderabad and the findings are presented in this paper.