The Genetic Basis for the Difference in Seed Weight Between Thatcher and Selkirk Wheats

The inbred backcross line method was used to study the genetics of the difference in seed weight between two hard red spring wheat cultivars, Thatcher and Selkirk. Three major genes, one with large and two with relatively small but equal effects, were found to control the difference. The distribution of the alleles was unidirectional with Thatcher carrying the alleles for light and Selkirk carrying the alleles for heavy seed. Linkage, dominance, and epistasis caused practically no bias in the analysis. The result indicates that breeding for seed weight should be simple.