Application of molecular markers and cytogenetic stocks to Brassica genetics, breeding and evolution

摘要

The genus Brassica includes three cultivated diploid species: B. nigra (2n = 16, genome B), B. oleracea (2n = 18, genome C) and B. rapa [Brassica campestris] (2n = 20, genome A), and three amphidiploid species: B. carinata (2n = 4x = 34, genomes BC), B. juncea (2n = 4x =36, genomes AB) and B. napus (2n = 4x = 38, genomes AC). Marker development and chromosome mapping have disclosed important information on the structure of these genomes. They are complex genomes, highly duplicated with intra- and intergenomic conservation of linkage blocks which permits homoeologous recombination. Chromosome maps are also being used to locate useful genes in vegetable and oilseed crops. Among the genes being mapped by various laboratories, disease resistance, cytoplasmic male sterility restorers and oilseed quality are the most prominent. As a case study, the detection is reported of markers associated with linolenic acid concentration and desaturases in B. napus and B. oleracea. Eventually, markers linked to these genes will be used for marker-assisted selection, gene isolation, molecular characterization and manipulation.