Inheritance of seed color in flax

Seed color of flax (Linum usitatissimum L.) is used in Canada to identify the two main market types. Traditional, high linolenic acid flax must have brown seed, while solin or zero linolenic acid flax must be yellow-seeded. The objective of this study was to determine the allelic-gene relationship of the dominant yellow gene, the variegated recessive gene, and various spontaneous and unknown recessive yellow genes in flax. Eleven flax cultivars or lines, four spontaneous recessive yellow seed mutants (YSED2, YSED4, S95407, and S96071), one recessive yellow European line (G-1186/94), two dominant yellow seed lines (CPI84495 and YSED18), one variegated line (M96006), and three brown lines ('ED47', 'Vimy', and 'CDC Bethune') were crossed in all possible combinations, excluding reciprocals. Test crosses were performed with four USDA-ARS introductions ('Minerva', 'Bolley Golden', 'Crystal', and 'Bionda') possessing the four different seed color genes, to determine which locus controlled the yellow-variegated seed color. Test cross data indicated that YSED2, YSED4, S95407, and S96071 possessed the same recessive allele of the g locus producing yellow seed. The European yellow line, G-1186/ 94, had a recessive allele at the d locus producing yellow seed, and a dominant yellow Y1 allele was carried by CPI84495 and YSED18. The variegated seed color was conditioned by a second recessive allele of the b1 locus, designated as b1(vg). Segregation analysis indicated that all the four loci governing seed color were inherited independently except for a possible weak linkage between g and b1(vg). The recessive genes (g, d, and b1(vg)) when homozygous recessive, were epistatic to the other loci carrying dominant alleles.