Evaluation of a divergent set of SSR markers to predict F1 grain yield performance and grain yield heterosis in maize

Previous work showed that many of the loci polymorphic between the Stiff St alk Synthetic and Lancaster Sure Crop heterotic group had allele frequency differences of 0.5 or more. These loci were also located in regions where l arge quantitative trait loci (QTL) have been detected for yield heterosis i n the cross between the widely used genetically divergent inbred lines B73 and Mo17. B73 and Mo17 represent one of the widely used heterotic maize gro ups in the U.S Corn Belt. It was hypothesized that 'perhaps those markers r esponsible for distinguishing heterotic groups are linked to loci that are responsible, in part, for heterosis.' The objectives of this study were to test tills hypothesis for maize hybrids with unrelated parents from widely used U.S. Corn Belt heterotic groups. In this study loci that were polymorp hic between the two heterotic groups and had allele frequency differences o f 0.40 or more were examined. F1 grain yield and grain yield heterosis were determined in a set of 59 crosses between unrelated parents that had been grown in a set of replicated experiments. The loci polymorphic with allele frequency differencess in these two heterotic groups were located in almost all of the regions identified previously as being polymer phic with allele frequency differences of 0.5 or greater between the Stiff Stalk;Synthetic and Lancaster Sure Crop lines. The Stiff Stalk Synthetic heterotic group wa s common to both studies but the Lancaster group was not. However, the sele cted loci in this study did not explain significantly more of the variation for Fl grain yield or grain yield heterosis than that explained using all of the loci studied.