Genetic location and characterization of chromosomal regions affecting second-generation European corn borer resistance in a maize population

Abstract

<p>Restriction fragment length polymorphisms (RFLPs) have been used to locate and estimate the effects of quantitative trail loci (QTL) for many complex traits in maize. The primary objective of this study was to locate and estimate the effects of genetic factors affecting resistance to second generation European corn borer (2ECB) tunneling and each of five morphological traits in a maize population. The second objective was to compare genetic location and effects of QTL over multiple environments. A restriction fragment length polymorphism (RFLP) based linkage map was developed for the population. Interval mapping and single-factor analysis of variance were used to identify chromosomal regions containing QTL;Eight QTL affecting 2ECB tunnel length were located to six chromosomes. Five QTL were detected in two of three environments, and three were unique to individual environments. Phenotypic variation explained by individual QTL ranged from 3 to 25%. Additive genetic effects were consistent between environments. Dominance effects for two QTL differed between environments in both direction and level of dominance. Epistasis was detected between one pair of loci affecting resistance to 2ECB tunneling;A total of 24 QTL were detected to affect five morphological traits: plant and ear heights, growing-degree-days (GDD) to pollen shed and silk emergence, and the GDD interval between pollen shed and silk emergence (silk-delay). Individual QTL explained from 8 to 25% of the phenotypic variation detected. Eleven QTL were detected in at least two environments. Additive genetic effects were generally consistent across environments, while dominance effects were variable.</p>