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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #104293
Title: RESTRICTION FRAGMENT LENGTH POLYMORPHISM MARKERS ASSOCIATED WITH SILK MAYSIN, ANTIBIOSIS TO CORN EARWORM (LEPIDOPTERA: NOCTUIDAE) LARVAE, IN A DENT AND SWEET CORN CROSS.

Author
item Guo, Baozhu
item ZHANG, ZHONGJUN - UGA, ENTOMOLOGY
item Widstrom, Neil
item SNOOK, MAURICE - UNIVERSITY OF GA
item Lynch, Robert
item PLAISTED, D - NOVANTIS SEEDS, INC.

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2000
Publication Date: 4/1/2001
Citation: Guo, B., Zhang,Z.J., Widstrom, N.W., Snook, M.E., Lynch, R.E., Plaisted, D. 2001. Restriction fragment length polymorphism markers associated with silk maysin, antibiosis to corn earworm (Lepidoptera: Noctuidae) larvae, in a dent and sweet corn cross. Journal of Economic Entomology. 94:564-571.

Interpretive Summary: Production of sweet corn with undamaged ears depends heavily on pesticides to reduce ear damage caused by the corn earworm. An estimated 25-40 insecticide applications may be made in a single season to control ear-feeding insects. Also sweet corn can serve as the major nurse crop for the corn earworm which eventually causes damage to other crops (e.g., field corn, cotton, peanuts, and many other vegetable crops). Therefore, development of resistance sweet corn lines would reduce the impact of pesticide application on the environment and lessen the impact of the pest for all crops. This study was to determine the genes controlling maysin (a natural insecticidal chemical) in a population developed from a cross between high-maysin field corn and low-maysin sweet corn and to develop sweet corn germplasm with resistance to ear-feeding insects. Using quantitative trait locus analysis, we identified a DNA marker ( p1) on chromosome 1S explained 25.6% of maysin variation and a second major gene (a1) on chromosome 3L accounted for 15.7% of the maysin variation. Consequently, marker-assisted selection based on results from this study will be a suitable breeding strategy for improving the resistance of sweet corn to corn earworm damage and reducing pesticide application.

Technical Abstract: Maysin, a C-glycosylflavone in maize silk, has insecticidal activity against corn earworm (Helicoverpa zea Boddie) larvae. Sweet corn (Zea mays L.) is a vulnerable crop to ear-feeding pests and depends on pesticide application to control insects which cause ear damage. This study was to identify maize chromosome regions (quantitative trait loci, QTL) associated dwith maysin synthesis in silks and eventually to develop sweet corn germplasm with resistance to ear-feeding insects. Using an F2 population derived from SC102 (high maysin dent corn inbred) and B31857 (low maysin sh2 sweet corn inbred), we examined the genetic mechanisms controlling the synthesis of maysin in silks. Single-factor analysis of variance revealed that npi286 (near p1, Bin 1.03) explained 25.6% of the phenotypic variance and a1 (Bin 3.09) accounted for 15.7% of the phenotypic variance. Locus a1 has a recessive gene action for high maysin with the presence of functional lp1 allele. Markers umc66a (near c2, Bin 4.07) and umc105a (Bin 9.02) also detected in this analysis with contribution of 2.8% and 2.3% to the phenotypic variance, respectively. A multiple-locus model, which included npi286, a1, csc3 (Bin 1.05), umc245 (Bin 7.05), agrr21 (Bin 8.09), umc105a, and the epistatic interactions npi286 x a1, a1 x agrr21, csu3 x umc245, and umc105a x umc245, explained 76.3% of the total phenotypic variance. Tester stock crosses showed that, at the a1 locus, SC102 has functional a1 alleles and B31857 has homozygous recessive a1 alleles. Consequently, marker- assisted selection based on results from QTL studies seems to be a suitable breeding strategy for improving resistance of sweet corn to corn earworm damage and reducing pesticide application.