Inheritance of Seed and Flower Color in Flax: A Comprehensive Genetic Study

Abstract Background: Flower and seed color are two important traits in flax breeding. Flower color is associated with the attraction of insects for pollination, and seed color affects the quality of oilseeds. Eight genetically diverse genotypes of flax with pairwise contrasting seed and flower color were crossed in all directions (56 crosses), and the inheritance mode of seed and flower color was studied in F1, F2 and F3 generations during 2015-2018. Results: Segregation patterns in F1 and F2 generations indicated that seed coat color is primarily determined by maternal genotype, but parents’ genetic constitution finally defines the expression of character. Segregation analysis in the F3 generation indicated that seed coat color is governed by three loci designated as G, D, and Y1. The inheritance patterns of seed color were either monogenic, strongly influenced by variation within a single gene, or epistatic due to interactions between two genes across different genetic backgrounds. Chi-square tests indicated that brown seed color was produced by recessive allele of the Y1 locus and dominant alleles of the G and D loci (GGDDy1y1). The yellow seed color was attributed to the homozygous condition of two recessive genes and one dominant gene (ggDDy1y1 and GGddy1y1) or homozygous condition of three dominant genes (GGDDY1Y1). Flower color was also found to be controlled by three loci assigned as B1, B2, and C′. Blue flower color is governed by dominant alleles at all three loci while, homozygous recessive at any of the three loci will result in a white flower. In the 56 crosses with similar and contrasting flower colors perfect segregating ratios of 3:1, 9:7, 13:3, and 27:37 blue to white flowers in the F2 generation suggested different epistatic interactions between these loci including duplicate-recessive and dominant-recessive. Conclusion: Overall, the findings of this study reveal that the genetic background influences trait inheritance in flax. Our results indicate that the three loci governing the seed color are different from the three controlling the flower color. Still, there is epistatic relationships among the genes for the two traits depending on the genetic background of the parental genotypes.