INHERITANCE OF ADULT-PLANT LEAF RUST RESISTANCE DERIVED FROM THE COMMON WHEAT VARIETIES EXCHANGE AND FRONTANA

Abstract

The inheritance of adult-plant resistance to race 5 of leaf rust was investigated in the varieties ''Exchange'' and ''Frontanar''. Two independently-inherited genes were identified and isolated, 1 from each of the varieties. The "Exchange" gene, designated as Lr12, conditions a type 2 reaction to race 5 and is partially dominant. The "Frontana" gene, designated as Lr13, conditions a 2+ reaction and is also partially dominant; however in "Manitou", which has adult resistance transferred from "Frontana", this gene is recessive. The Lr12 and Lr13 genes both require 1 or more modifiers to produce the fleck reaction characteristic of the parental varieties. Both genes give resistance to a wide range of races of leaf rust.