The chromosome complement of Brassica oleracea (2n = 18) was dissected by means of alien chromosome addition lines generated by successive backcrosses of either of two B. campestris accessions (2n = 20) to the resynthesized B. napus 'Hakuran' (2n = 38). Alien chromosome addition lines were characterized by chromosome counts, morphology, pollen and seed fertility, and transmission of chromosome-specific markers. Mean chromosome number in the first backcross generation was approximately 23.5 and was little influenced by the B. campestris accession. Fertility and isozyme marker transmission were also not affected by choice of B. campestris accession. Transmission of chromosome-specific markers to the BC2 was more variable than to the BC1, and appeared to be affected by the B. campestris recurrent accession. Twenty-five monosomic addition lines (2n = 21) were recovered in the second backcross generation, representing 7 of the 9 B. oleracea synteny groups. One monosomic alien chromosome decreased seed fertility but not pollen fertility. Only one monosomic addition could be reliably identified morphologically.Key words: chromosome markers, aneuploidy, restriction fragment length polymorphism, isoymes.
Construction of a complete set of alien chromosome addition lines from Gossypium australe in Gossypium hirsutum: morphological, cytological, and genotypic characterization
