EVIDENCE FOR COMPLEMENTARY GENE ACTION CONFERRING RESISTANCE TO PUCCINIA GRAMINIS AVENAE IN AVENA SATIVA

Abstract
Plants derived from a cross between the oat cultivar Kyto (A. sativa L.) and A. steriis L. were highly resistant to oat stem rust (P. graminis Pers.) in the adult plant stage. This resistance was much superior to that of either parent. This is the 1st example of transgressive segregation in this host-parasite system. The genetic mechanism of the resistance is not completely understood, but the resistance apparently is conferred by gene Pg-12 from ''Kyto'' interacting with a 2nd gene. An alternate hypothesis is that a suppressor gene in ''Kyto'' prevents the resistance conditioned by Pg-12 from being expressed in the adult plant stage. This type of resistance is highly effective against all but 2 of the oat stem rust races known to occur in North America.