Somatic Hybridization Between Brassica Napus And Orychophragmus Violaceus

Orychophragmus violaceus (L. ) O. E. Schulz is a member of the Brassiceae tribe. Superior oil quality, characterized by the high contents of linoleic (53. 17%), oleic acid (20. 32% ) and palmitic (14. 31%) acids, and the low contents of linolenic (4. 76%) and erucic (0. 94%) acids, together with good yield components such as many branches and large seeds, makes it a potential genetic resource for Brassica oilseed crop improvement. The hybridizations between Brassica napus L. (2n=38, genomes AACC) and O. violaceus, for transfer of these useful traits into oilseed rape have been attempted by sexual means and protoplast fusions, and the separation of parental genomes during the mitotic and meiotic divisions of the hybrid cells was proposed in the sexual hybrids. In order to study the cytology of symmetric and asymmetric somatic plants, the somatic hybrids of O. violaceus with B. napus were obtained again and investigated by the methods of cytogenetics and genomic in situ hybridization (GISH). The results were described as follows.(1) Somatic hybridization of B. napus with wild relatives was carried out and the technical system of plant regeneration was established. There are many factors affected the regeneration frequency of the B. napus and O. violaceus protoplasts, among which genotype and culture conditions had a significant impact on cell division and shoot regeneration frequency. The culture conditions covered the combinations of enzyme for protoplasts isolation, pH and combinations of medium, the proportion and sorts of hormone, the density of the protoplasts and so on.(2) Asymmetric fusion plants between the two species were obtained, and were mixploids with the 48～62 chromosome numbers in ovary cell. The hybrids wre classified into two types according to their morphology and cytology, (1) the plant No.100 were completely sterile of male and female and produced no progeny from the backcross with B. napus and O. violaceus. (2)The three plants No.101-1, -2, -3 were male-sterile and gave 10 embryoes after backcrossing to B. napus. No.100 plant was small and similar to B. napus morphologically, but three plants No.101-1, -2, -3 possessed a intermediate morphology...