Diallel analysis of mature plant resistance to Helminthosporium maydis in maize.
Six inbreds and their 15 single-cross hybrids were evaluated under natural infection by H. maydis [Cochliobolus heterostrophus] race O in the autumn of 1991 and spring of 1992. Inbred lines Antigua-2D and Sw654 showed that highest level of mature plant resistance and this was consistent between crop seasons. Both general (GCA) and specific (SCA) combining ability were highly significant for resistance in both autumn and spring. Additive effects accounted for a major part of the total variation. These results indicated that pedigree or recurrent selection methods should be effective in breeding for improved resistance to southern leaf blight.