Quantitative trait locus (QTL) and QTL x environment (E) interaction effects for agronomic and malting quality traits were measured using a 123-point linkage map and multi-environment phenotype data from an F1-derived doubled haploid population of barley (Hordeum vulgare). The QTL × E interactions were due to differences in magnitude of QTL effects. Highly significant QTL effects were found for all traits at multiple sites in the genome. Yield QTL peaks and support intervals often coincided with plant height and lodging QTL peaks and support intervals. QTL were detected in the vicinity of a previously mapped Mendelian maturity locus and known function probes forα- andβ-amylase genes. The average map density (9.6 cM) should be adequate for molecular marker-assisted selection, particularly since there were few cases of alternative favorable alleles for different traits mapping to the same or adjacent intervals.

ABSTRACT.The ae (amylose extender) recessive mutant alleles in maize are an important genetic resource for the development of highamylose cultivars. On the basis of ae allele sequences (from the National Center for Biotechnology Information), the ae mutant alleles were cloned from high-amylose maize and the allelic Ae gene from common maize luyuan92 inbred lines. Five pairs of primers were designed to screen for a molecular marker of ae alleles, yielding a dominant molecular marker, ae474. We used 53 types of high-amylose maize and common maize inbred lines and their hybrid and backcross offspring for verification and analysis. The ae dominant molecular marker was effective in selecting for the ae alleles and for biological materials with a high-amylose genotype. Presence and absence of the marker in the offspring conformed to the expected Mendelian ratios. Using this marker, we were able to detect the ae alleles in a backcross and its second generation more efficiently (53.3 and 73.3%, respectively) than was possible without marker selection. These data indicate that the marker can be used as a tool to improve selection efficiency and accelerate the cultivation of new varieties of high-amylose maize.