Inheritance of blast resistance and its allelic relationship with five major R genes in a rice landrace “Vanasurya”

A rice landrace “Vanasurya” was identified to be blast resistant after multilocation evaluation under uniform blast nursery (UBN). The F2population derived from the cross between Vanasurya x susceptible rice cultivar, CO 39 showed a segregation of 3R:1S, which revealed that the resistance to blast disease is governed by a single dominant gene. Test of allelic relationship of blast resistance in the landrace, Vanasurya with known major blast resistance genes, viz. Pi1 , Pi9 , Pita , Piz5 and Pi54 by crossing it with the monogenic blast differentials showed that blast resistance gene in Vanasurya was allelic to Pita whereas it was non-allelic to other genes tested. This was further confirmed through molecular marker analysis with a gene based marker YL155/87 for Pita .