The effect of vernalization genes on earliness and related agronomic traits of spring wheat in northern growing regions

Vernalization response (Vrn) genes play a major role in determining the flowering times of spring-sown wheat (Triticum aestivum L.). The objective of this study Was to investigate the effect of Vrn genes on flowering and maturity times and important agronomic traits in a set of reciprocal whole-chromosome substitution lines and eight western Canadian spring wheat cultivars of known Vrn genes, grown over three seeding dates Canada over 2 yr. The genotype carry,in Alberta, ing sprinq habit alleles at Vrn-A1, Vrn-B1, and Vrn-D5 flowered and matured the earliest, and had grain protein content but the lowest grain yield. Genotypes with spring habit alleles Vrn-A1 and Vrn-B1 were early maturing and high yielding. Genotypes with the spring habit Vrn-D5. allele either singly or in combination with Vrn-A1 were late maturing. The spring habit allele of Vrn-A1 was not completely epistatic to Vrn-B1 and Vrn-D5 for flowering or maturity time. The spring habit allele of Vrn-B1, however, was epistatic to that os Vrn-D5. In northern wheat growing regions, breeding preference should be given to Vrn genotypes with three spring habit alleles or those with spring habit alleles of Vrn-A1 and Vrn-B1. Genotypes carrying spring habit Vrn-D5 allele singly or in combination with Vrn-A1 should be planted as early in the growing season as possible to realize their full yield potential.