|Snook, Maurice - UNIV OF GEORGIA-ATHENS|
|Coe Jr, Edward|
Submitted to: Corn and Sorghum Improvement Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 4, 1997
Publication Date: N/A
Technical Abstract: We used quantitative trait locus (QTL) methodology to identify genetic factors controlling maysin concentration in silks of four maize, Zea mays L., populations. Maysin is a C-glycosyl flavone that inhibits growth of the corn earworm (CEW), Helicoverpa zea (Boddie), which feeds initially on young silks. In the population (GT114 x GT119)F2, over half of the phenotypic variation in maysin concentration was accounted for by the regulatory locus p1. A region on chromosome 9S accounted for 11% of the variation, but its effect was expressed only when the pathway was activated by a functional p1 allele. Population (GE37 x FF8)F3 revealed major effects on maysin concentration and CEW larval growth on chromosomes 2 and 6; candidate loci in these regions include whp1 and sm1. However, a region on chromosome 9S had a large effect on maysin level, but none on larval growth. Separate genetic control of closely related flavonoid compounds was inferred from results for the population (GT114 x NC7A)F2. We detected a large influence on maysin concentration on chromosome 9S, while apimaysin concentration was primarily affected by the pr1 region of chromosome 5. Partial results from the population (GE37 x Mp464)F2 indicated a major effect on maysin in the chromosome 9S region, and smaller effects in the p1 region of chromosome 1 and the c2 region of chromosome 4. One of our most intriguing results is the detection of a significant QTL in the same region of chromosome 9S in all four populations. Our future efforts will include investigations of the nature of the effect of that locus.