Genetic analysis of heading date in winter and spring wheat

Climate change will have severe effects on wheat production, but crop phenology can be an important component of wheat adaptation. In this study, elite soft winter wheat and hard spring wheat (HSW) populations were phenotyped for heading date (HD) in North America and Tanzania (HSW only). All lines were genotyped with common single nucleotide polymorphism markers to compare the genetics and prediction accuracy of genomic selection (GS) for HD in winter and spring wheat. Lines were tested under diverse environments and the HSW germplasm was assessed for their early maturity performance in Africa. Two clusters of environments were formed for each population. One cluster consisted of southern environments and the other consisted of northern environments. The latter produced a more narrow range of HD than the southern cluster. Thirteen highly significant (p < 0.0005) quantitative trait loci (QTLs) for HD were detected in two populations. Within each population, the QTL effects were consistent between clusters of environments. Within each population, GS model developed using data from one cluster of environments could predict HD in the other cluster. The prediction accuracy of GS between two populations was minimal. Similarly, only a few minor effects QTL were in common between the two populations. Additionally, we identified 15 spring wheat genotypes with HD earlier than commercial Tanzanian wheat varieties. These genotypes could be used as a resource for creating early HD wheat varieties for Tanzania.