GENETIC-VARIATION WITHIN AND AMONG DIFFERENT CULTIVARS AND LANDRACES OF BRASSICA-CAMPESTRIS L AND BRASSICA-OLERACEA L BASED ON ISOZYMES

Genetic variation based on isozymes was studied in 43 landraces and cu ltivars of Brassica campestris from China, 4 cultivars of B. campestri s from Sweden and 1 from India, and 5 cultivars of B. oleracea from Sw eden and 1 from China (B. alboglabra). A total of 17 isozyme loci was studied, 10 of these were polymorphic in B. campestris and 6 were poly morphic in B. oleracea. The level of heterozygosity seemed to be reduc ed in the Swedish cultivars compared to the Chinese landraces and cult ivars of B. campestris. The level of heterozygosity in B. oleracea was even lower than that in the Swedish cultivars of B. campestris. A phy logeny of the cultivars and landraces of B. campestris showed that the B. campestris var 'yellow sarson' cultivar, originating from India, d eviated significantly from the other cultivars of B. campestris. A phy logeny of the cultivars of B. oleracea confirmed the expectations that the cultivar B. alboglabra was not closely related to the cultivated forms of B. oleracea.