Restriction fragment length polymorphism markers associated with silk maysin, antibiosis to corn earworm (Lepidoptera : Noctuidae) larvae, in a dent and sweet corn cross

Maysin, a C-glycosylflavone in maize silk, has insecticidal activity agains t corn earworm, Helicoverpa zea (Boddie),larvae. Sweet corn, Zea mays L., i s a vulnerable crop to car-feeding insects and requires pesticide protectio n from ear damage. This study was conducted to identify maize chromosome re gions associated with silk maysin concentration and eventually to transfer and develop high silk maysin sweet corn lines with marker-assisted selectio n (MAS). Using an F-2 population derived from SC102 thigh maysin dent corn) and B31857 (low maysin sh2 sweet corn), we detected two major quantitative trait loci (QTL). It was estimated that 25.6% of tile silk maysin variance was associated with segregation in the genomic region of npi286 (flanking to p1) on chromosome 1S. We also demonstrated that a1 on chromosome 3L, had major contribution to silk maysin (accounted for 15.7% of the variance). L ocus nl has a recessive gene action for high maysin with the presence of fu nctional p1 allele. Markers umc66a (near c2) and umc105a on chromosome 98 a lso were detected in this analysis with minor contribution. A multiple-locu s model, which included npi286, a1, csu3 (Bin 1.05), umc245 (Bin 7.05), agr r21 (Bin 8.09), umc105a, anti the epistatic interactions npi286 X al, al X agrr21, csu3 X umc245, and umc105a X umc245, accounted for 76.3% of the tot al silk maysin variance. Tester crosses showed that at the al locus, SC102 has functional Al alleles and B31857 has homozygous recessive (II alleles. Individuals of (SC102 X B31857) X B31857 were examined with MAS and plants with p1 allele from SC102 and homozygous a1 alleles from B31857 had consist ent high silk maysin. Marker assisted selection scents to be a suitable met hod to transfer silk maysin to sweet corn lines to reduce pesticide applica tion.