Resynthesis of Brassies napus L. through Interspecific Hybridization between B. alboglabra Bailey and B. campestris L. with Special Emphasis on Seed Colour

Brassica napus L. was resynthesized through interspecific hybridization between B. alboglabra Bailey and B campestris L. with the objective or developing yellow-seeded forms of this species. For hybridization, one black-seeded form and one light brown-seeded form of B. alboglabra (a subordinate of B. oleracea) and one brown and ten yellow-seeded forms of B. campestris were chosen as parents. Crosses with B. alboglabra as the female parent were more successful than crushes with B. campestris as female. The use of the embryo rescue culture technique greatly increased the number of surviving hybrid embryos. Colchicine treatment was required for doubling the chromosome number of the amphihaploid hybrid plants. In the newly-resynthesized rape forms, the white petal of B. alboglabra was partially epistatic over the yellow petal of B. campestris. The self compatibility of B. alboglabra was hypostatic to the self incompatibility of B. campestris. The black-seeded character of B. alboglabra and the brown-seeded character of B. campestris were completely eptstatic over the yellow-seeded character of B. campestris and the light brown-seeded character of B. alboglabra. Implications of the results from this study in breeding yellow-seeded B. napus are discussed.