The inheritance of seed colour and vernalization requirement in Brassica napus using doubled haploid populations

Summary In the Mediterranean coastal region, spring barley cultivars are sown in the autumn, corresponding with the rainy season. Thirty eight cultivars out of 44 spring which were collected from North African countries including Morocco, Algeria, Tunisia, Libya and Egypt were of a single dominant spring gene type (+Sh₂+). Almost the same situation was found in Spain, Italy and Greece, with exceptions for France and Turkey. Kernel row of North African cultivars was characterized by six-rowed type, though there was one exception in Egypt. In the South European countries of Spain, Italy and Greece, six-rowed type varieties were also prevalent. As to non-brittle rachis, in North African countries oriental type cultivars (Btbt₂) were much higher in frequency than occidental type cultivars (btBt₂), while in European countries, occidental type cultivars were rather dominant, except for Italian cultivars. In Turkey, located in the joint area between Europe and Asia, cultivars tested were mostly occupied by spring genotype other than +Sh₂+, and also characterized by tworowed head and occidental type for non-brittle rachis. In the Mediterranean coastal region, especially in North Africa, restricted genotypes, +Sh₂+ for spring growth habit and v for six-row may indicate adaptability favorable to the growth conditions in these areas. Furthermore, North African cultivars were characterized by the oriental type of non-brittle rachis. This may give us information about the migratory routes of the original landrace to North Africa.