The Inheritance of Seed Color in a Resynthesized Brassica Napus Line No. 2127-17 including a New Epistatic Locus

摘要

Yellow seed is an important trait in Brassica napus. To know the genetic basis of yellow seed color in Brassica napus, we carried out genetic studies by using conventional genetics analyses. The conventional genetics was studied in generations (F_1, F_2, reciprocal F_2, BC_1 and F_(23)) of B. napus derived from crosses between a yellow-seeded (No. 2127-17) and nine different black-seeded parents. The results indicated that seed color was mainly controlled by the maternal genotype but influenced by the interaction between the maternal and endosperm and/or embryonic genotypes. In the combinations which included black-seeded lines SW0780, 94560, 94545 and 1141B, the yellow seed is partially dominant over black with two or three dominance epistasis ratio. A dominant yellow'seeded gene Y which exhibits epistatic effects on the two independent dominant black-seeded genes B and C was identified in DH line No. 2127-17. These observations are in agreement with our previous reports. But in the rests, including the crosses with HS No. 4, HS No. 3, XY No. 15, 94570 and ZS No. 10, the black seed color was dominant over yellow seed color. The inheritance of this trait in the segregating populations fits the model of a digenic dominance epistasis or triplicate dominance epistasis. A new locus was identified and designated as D: the dominant gene D for black seed color inhibits the dominant gene Y. Therefore, in combination with the Y, B and C, we found that the seed color was influenced by at least four genes.Identifying seed color genes and defining their inheritance should further our imderstanding of yellow seed color trait and facilitate development of new and better yellow-seeded cultivars of Brassica napus.