Comparative mapping in F-2:3 and F-6:7 generations of quantitative trait loci for grain yield and yield components in maize

This study was conducted to compare maize quantitative trait loci (QTL) detection for, grain yield and yield components in F-2:3 and F-6:7 recombinant inbred (RI) lines from the same population. One hundred and eighty-six F-6:7 RIs from a Mo17xH99 population were grown in a replicated field experiment and analyzed at 101 loci detected by restriction fragment length polymorphisms (RFLPs). Single-factor analysis of variance was conducted for each locus-trait combination to identify QTL. For grain yield, 6 QTL were detected accounting for 22% of the phenotypic variation. A total of 63 QTL were identified for the seven grain yield components with alleles from both parents contributing to increased trait values. Several genetic regions were associated with more than one trait, indicating possible linked and/or pleiotropic effects. In a comparison with 150 F-2:3 lines from the same population, the same genetic regions and parental effects were detected across generations despite being evaluated under diverse environmental conditions. Some of the QTL detected in the F-2:3 seem to be dissected into multiple, linked QTL in the F-6:7 generation, indicating, better genetic resolution for QTL detection with RIs. Also, genetic effects at QTL are smaller in the F-6:7 generation for all traits.