Thursday, November 16, 2006 - 9:00 AM

Genetic and QTL Analysis of Pericarp Thickness and Ear Inflorescence Architecture in South Korean Waxy Corn Germplasm.

Eunsoo Choe, University of Illinois, AW-101 Turner Hall 1102 S. Goodwin Ave., Urbana, IL 61801 and Torbert Rocheford, AW-101 Turner Hall, 1102 S Goodwin Ave, Urbana, IL 61801.

Consumption of fresh waxy corn is widespread among Asian people for its tenderness, sweetness, and stickiness. Due to increasing Asian-American population and market, breeding and genetic research on waxy corn for U.S. fresh consumption is needed. Marker assisted selection of QTL for introducing favorable characteristics from exotic varieties to more adapted U.S. background would enhance breeding success. Objectives of this study were to detect QTL for pericarp thickness, which affects tenderness and for ear inflorescence architecture traits are relevant to consumer preference and yield and study the genetic relationships among traits using principal components analysis (PCA). Evaluations were performed on 264(BH20xBH30)F3 families. BH30 has thinner pericarp thickness than that of BH20 and both are waxy corn inbreds from South Korea. 100 SSR markers were mapped. Forty-one QTL were detected for five different pericarp thickness traits measured on the upper germinal, lower germinal, upper abgerminal, lower abgerminal and crown regions. QTL for pericarp thickness traits explained from 31.7 to 42.3% of phenotypic variation. Most allele for thin pericarp thickness were from BH30. Transgressive segregation and some significant epistatic interactions were detected. PCA showed the first principal component (PC) explained 87.6% of pericarp trait variation, and eight PC-QTL were detected. Forty-six QTL were detected for ear inflorescence architecture traits measured on cob length, ear and cob diameter, kernel depth, number of kernels per row, number of row per ear, kernel thickness, ear and cob weight, and kernel weight. QTL for these traits explained from 8.7 to 32.8% of the phenotypic variation. Four PCs for ear inflorescence architecture traits explaining 81.8% of total phenotypic variation, and twenty-two PC-QTL were detected. Notably, QTL regions significant for two or more ear inflorescence architecture traits and PC-QTL were detected in bins 1.08(id1), 3.04(ts4, lg3), 4.05(fea2), 7.02(ra1) and 8.05(knox5) which have known inflorescence mutants and genes.