Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2007
Publication Date: 2/5/2007
Citation: Williams, M., Pataky, J.K., Riechers, D.E. 2007. Prevalence of a gene conferring sensitivity to nicosulfuron and mesotrione in sweet corn and field corn [abstract]. Weed Science Society of America Meeting Abstracts. Paper No. 181.
Technical Abstract: In previous research, a single gene in a herbicide-sensitive sweet corn inbred, Cr1, conditioned sensitivity to nicosulfuron, mesotrione and other postemergence herbicides. Many other sweet corn hybrids and inbreds and certain field corn inbreds also have been noted as being sensitive to certain postemergence herbicides. The objective of this study was to determine the prevalence of the gene from Cr1 in other herbicide-sensitive maize germplasm. Fifty-four sweet corn hybrids, 39 sweet corn inbreds, and 37 field corn inbreds were selected based on sensitive reactions to one or more herbicides. Hybrids and inbreds were crossed with Cr1 and with Cr2 (a nicosulfuron- and mesotrione-tolerant sweet corn inbred). Inbreds also were crossed with nicosulfuron-sensitive field corn inbreds, GA209, B90 or B94. Hybrids were self pollinated to produce the F2 generation. The F2 generation of the cross of sweet corn inbreds with Cr1 also were produced by self-pollinating F1 plants. Responses to nicosulfuron and mesotrione were assessed in field trials in 2006 for inbreds, hybrids and progeny from the various crosses. Based on phenotypic responses of sweet corn hybrids, crosses of hybrids with Cr1 and Cr2, and progeny from the F2 generation of hybrids, 33 sweet corn hybrids were classified as heterozygous for a gene conferring nicosulfuron sensitivity, eight were homozygous for sensitivity, and nine were homozygous for tolerant responses. Based on 1:1 segregation of progeny from the cross of each hybrid x Cr1, we concluded that all 33 hybrids heterozygous for a herbicide-sensitivity gene were allelic with Cr1. Similarly, 27 sweet corn inbreds appeared to be sensitive to nicosulfuron and allelic with Cr1; whereas 11 were nicosulfuron tolerant. Seventeen dent corn inbreds appeared to be sensitive and allelic with Cr1, and 11 were tolerant. Responses of some inbreds and hybrids could not be classified easily based on the number of progeny sampled in the first trial of this study. Sweet corn inbreds and hybrids that were sensitive to nicosulfuron and mesotrione and allelic with Cr1 came from 11 different seed or food processing companies that represent the majority of sweet corn production in the US. The 17 sensitive field corn inbreds originated from 13 different public breeding programs. Hence, a gene that conditions sensitivity to nicosulfuron, mesotrione, and potentially to several additional postemergence herbicides, is prevalent in sweet corn germplasm used commonly in breeding programs in North American, and it occurs in various sources of public field corn germplasm.