In wheat (Triticum aestivum L.), major determinants of plant phenology are physiological responses to vernalization temperature, and day length (photoperiod), conditioned by VRN and the PPD genes, respectively. The objectives of this research were to characterize the allelic variation at the major VRN and PPD loci in a diverse panel of winter wheat genotypes (n = 208) and to associate the allelic variation with phenologic, agronomic and adaptation traits. The panel was genotyped using allele-specific markers of the major VRN and PPD loci; VRN-A1, VRN-B1, VRN-D1, VRN-B3, PPD-A1, PPD-B1, and PPD-D1. The photoperiod-sensitive alleles Ppd-D1b and Ppd-A1b were present in 127 and 166 genotypes, respectively. Genotypes with different alleles at PPD-D1 and PPD-A1 varied for number of days to booting, heading, anthesis, and maturity as well as, height and yield. Variation at the VRN loci was minimal. Genotypes with photoperiod-insensitive alleles had higher stability for days to anthesis, than photoperiod-sensitive genotypes.