Resistance to corn borer in crosses between sweet and field corn populations

摘要

Field corn (Zea mays L.) is more resistant to corn borers than is sweet corn. The objective of this work was to determine the best combination of field and sweet corn germplasm for improving resistance of sweet corn to corn borers. A diallel cross was made among three field corn synthetic cultivars (EPS6(S)C3, EPS7(S)C3, and EPS10) and three sweet corn cultivars (Golden Bantam, Stowell's Evergreen, and Country Gentleman) that were evaluated in Spain for 2 years under artificial infestation with eggs of pink stem borer (PSB) (Sesamia nonagrioides Lefebvre) or European corn borer (ECB) (Ostrinia nubilalis Hubner), natural infestation by these insects, or protected with a pesticide. Plants infested artificially with PSB were the most damaged. Natural infestation by PSB was high. Larvae were more abundant in the stems than in the ears. The field corn synthetics, particularly 'EPS7(S)C3', had more favorable variety effects for resistance traits than the sweet corn cultivars, 'Country Gentleman' being the poorest. For the sweet x field corn crosses, 'EPS10' x 'Golden Bantam', 'EPS10' x 'Stowell's Evergreen', and 'EPS6(S)C3' x 'Country Gentleman' had the highest heterotic (h(jj)) effects for yield under PSB infested conditions. The crosses 'EPS6(S)C3' x 'Golden Bantam' and IEPS7(S)C3' x 'Stowell's Evergreen' had the lowest heterotic effects. The crosses 'EPS6(S)C3' x 'Golden Bantam' and IEPS7(S)C3' x 'Stowell's Evergreen' appear the best for improving yield under infested conditions of the sweet corn heterotic pattern 'Stowell's Evergreen' x 'Golden Bantam'.