Abstract
Genetic segregations for six enzyme-coding loci were studied in the F2 progenies obtained from interspecific hybrids between B.vulgaris and B.macrocarpa. The loci identified are Got-2. Lap, Gdh-2, Aph-1, Px-1, and Px-2. Px-1 and Px-2 were tightly linked with each other, of which the latter locus was expressed only in B.macrocarpa. Got-2, Lap and Gdh-2 exhibited a distorted segregation that deviated from the expected Mendelian ratio. The segregation of Got-2 showed a significant excess of the B.macrocarpa allele, whereas a marked deficiency of the allele was observed for Lap and Gdh-2. The distortion appeared to be caused by the linkage with the genes responsible for reproductive barriers found in the hybrids. B.vulgaris, B.maritima and B.atriplicifolia had most of the alleles in common, whereas B.macrocarpa had many unique alleles that were not detected or at least were rare in the former three species, suggesting that B.macf-ocarpa may be the most different species in the section Vulgares. B.patula and B.adanensis were also slightly different from B.vulgaris, B.maritima and B.atriplicrfolia. Of the former two species, B.adanensis was the most similar to B.macrocarpa in the section.
