European Corn Borer Resistance in Half‐Sib Families from a Sorghum Random‐Mating Population 1

One hundred half‐sib families from a sorghum [ Sorghum bicolor (L.) Moench] random‐mating population were artificially infested with European corn borer [ Ostrinia nubilalis (Hubner)] egg masses, and the same families were treated with an insecticide to reduce natural infestation. A two‐replicate split‐plot design with treatments as whole plots and families as subplots was used for 2 years. Agronomic effects of insect damage were assessed, and a quantitative genetic analysis provided information for use in recurrent selection. Total grain yield (including that from lodged stalks and heads) was reduced 13.0% by infestation and subsequent damage, combine grain yield (excluding lodged stalks and heads) was reduced 18.4 %, and potential yield loss (excluding all unlodged stalks and unfallen heads with borer cavities plus lodged stalks and heads) was 48.7%. Weight of 100 seeds determined from total grain yield samples was reduced 7.9 % by infestation. Borer damage (breakage) traits generally had strong negative correlations with grain yield in the infested families. Total grain yield, combine grain yield, seed weight, and stalk breakage had heritabilities of 0.60, 0.64, 0.80, and 0.56, respectively, in the infested families. Selection for these traits, in the presence of borers, should initially improve a population for resistance to the European corn borer. Head damage was determined easily by hand breakage but had a heritability of only 0.32 because of a high family ✕ year interaction and a seemingly nonrandom distribution.