Distributions for European Corn Borer (Lepidoptera: Pyralidae) Resistance Ratings of S1 Lines from ‘BS9’ Corn

Abstract

A corn (Zea mays L.) cultivar, ‘BS9’, was evaluated to determine effectiveness of four cycles of S1 recurrent selection to improve S1 line performance for resistance to European corn borer, Ostrinia nubilalis (Hübner). One hundred S1 lines from the base population (C0) and the population from the fourth cycle of selection (C4) were evaluated for first-generation resistance, second-generation resistance, an thesis date, and stalk rind puncture. On a scale from 1, highly resistant, to 9, highly susceptible, mean first-generation damage ratings decreased significantly from 4.3 in the C0 to 3.0 in the C4, and mean second-generation damage ratings decreased significantly from 5.8 in the C0 to 3.9 in the C4. Significant differences were also detected for an thesis date and stalk rind puncture. Genetic variance, entry mean heritability estimates, and frequency distributions indicated that further selection for first-generation resistance is not necessary, but further progress would be desirable for second-generation resistance in ‘BS9’. No significant correlations were found in either S1 population between first-generation and second-generation resistance or stalk rind puncture with first-generation or second-generation resistance.