Characterization of interspecific hybrids between Chinese cabbage (Brassica rapa) and red cabbage (Brassica oleracea)

Interspecific hybridization is an excellent way to create germplasm resources and is considered an important driver of genome evolution. We selected one Chinese cabbage variety and one red cabbage variety for hybridization. Heterologous haploid offspring were obtained by embryo rescue, and heterologous diploids were obtained by colchicine-induced chromosomal doubling. The field traits and simple sequence repeat markers of 98 F2 plants were investigated. The result showed that the parental traits were separated in the hybrids, with traits tending to shift from those of Chinese cabbage to those of red cabbage, and trait values showed normal distributions. Simple sequence repeat patterns varied, with the number of missing bands being significantly greater than that of novel bands in hybrids. Thus, the phenotypes of the early formed allopolyploids were unstable and accompanied by dramatic changes in the genome. This study not only increased the genetic resources available for B. napus but also laid a theoretical foundation for exploring trait segregation in early formed allopolyploids.