Allelic shifts and quantitative trait loci in a recurrent selection population of oat

Recurrent selection to enhance grain yield of oat (Avena sativa L.) has been ongoing at the University of Minnesota since 1968. Grain yield was increased by 21.7% after seven cycles of recurrent selection. The objectives of this study were to monitor the long-term genetic changes in this recurrent selection population using restriction fragment length polymorphisms (RFLPs). Ninety-seven RFLP loci detected by 73 cDNA clones were used to evaluate changes in allelic frequencies during the recurrent selection process. Significant allelic shifts were detected in eight genomic regions. Four linkage groups were studied in greater detail to localize putative quantitative trait loci (QTL). In total, seven primary or major QTL regions were identified using allelic shift, correlation, and single-factor analysis of variance (ANOVA) data. Six of these regions were associated with grain yield and one was associated with plant height. Thirty-three other minor QTL were detected using correlation and/or ANOVA data. Multiple regression models for grain yield, heading date, and plant height indicated that associated markers accounted for 30, 38, and 27% of the phenotypic variance, respectively. Our results indicate that we have identified genomic regions containing favorable alleles selected during the recurrent selection process. Thirteen of the 40 QTL identified for the individual traits in the recurrent selection population were previously identified in the Kanota X Ogle recombinant inbred mapping population. Therefore, these QTL may be generally important in oat.