Submitted to: Journal of Genetics and Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 27, 2000
Publication Date: N/A
Interpretive Summary: The fall armyworm is a major insect pest of field and sweet corn in many parts of the Americas. Infestations of fall armyworm often reach devastating levels in the southern USA with yield losses up to 2% annually. Fall armyworm damage is often a limiting factor in the production of late-planted sweet corn. Knowledge of how resistance to fall armyworm is inherited in sweet corn would be useful to plant breeders in developing effective breeding strategies for incorporating resistance into new sweet corn germplasm lines. In this investigation, 11 supersweet corn lines were crossed to Mp708, a fall armyworm resistant field corn germplasm line developed by USDA, ARS scientists at Mississippi State, MS. An evaluation of the segregating F2 populations indicated that fall armyworm resistance was highly heritable and was not linked to the gene for sweetness. Mp708 was a good source of resistance to fall armyworm and should be useful to plant breeders incorporating resistance into sweet corn hybrids. Growing resistant hybrids will reduce the need for insecticides in sweet corn production.
Technical Abstract: Fall armyworm is a major insect pest in field and sweet corn in many parts of the Americas. Knowledge of the heritability of fall armyworm resistance in sweet corn would help breeders to more effectively plan strategies for incorporating resistance into new corn germplasm. The objectives of this study were to estimate heritability for fall armyworm resistance and predict selection gain in sweet corn. Seven inbred lines and four commercial single cross sweet corn hybrids, all homozygous for the shrunken-2 gene for sweetness, were crossed to Mp708, a fall armyworm resistant field corn line. The F2 populations were subdivided with half being selected for the shrunken-2 trait and the other half left unselected. Parents and their respective F2 populations were artificially infested with fall armyworm larvae and evalauted for leaf feeding damage. Heritability estimates ranged from 0.22 to 0.93 depending on the method of estimation. Populations homogeneous for shrunken-2 resulted in higher than expected gains in resistance; however, resistance to fall armyworm damage did not appear to be linked to the shrunken-2 gene.