Exploring the Genetics of Earliness in the CDC Teal × CDC Go Canadian Western Red Spring Wheat Mapping Population

In the spring growing regions of western Canada, early maturity is an important trait for timely harvest to avoid frost during the grain fill period and associated harvest and post-harvest problems. Earliness is genetically regulated by vernalization, photoperiod, earliness per se genes and complex gene interactions. In this study, we explored effect of these gene complexes on expression of 10 agronomic traits and grain protein concentration in the CDC Teal × CDC Go Canadian western red spring wheat mapping population. The population of 187 recombinant inbred lines was genotyped with 341 DArT polymorphic markers and a functional Vrn-B1 marker; and phenotyped over three years in replicated yield trials near Edmonton AB Canada. The dominant allele of Vrn-B1 lessened the number of days to heading, flowering and maturity, and increased leaf color concentration and plant height. A total of 21 QTLs were found for all agronomic traits except plant height and grain protein concentration. Two earliness per se QTL were mapped to chromosomes 1A (QEps.dms-1A) and 4A (QEps.dms-4A) in all three growing seasons, contributing 15-27% and 8-10% to the total genetic variation of early maturity, respectively. Our results suggest that these two earliness QTLs and Vrn-B1 exhibited additive interaction and a combination of three dominant alleles headed, flowered and matured 1.7, 1.9 and 4 days earlier, respectively, than lines with all recessive alleles.