Genetic Mapping, Quantitative Trait Analysis, and Gene Cloning in Brassica oleracea

Among the cultivated Brassica species, B. oleracea is among the most genetically and morphologically diverse species. The modern crop forms of B. oleracea have been cultivated and selected for centuries together with the diverse range of wild forms found in this species and closely related species, which played important roles in creating variation in B. oleracea and other cultivated Brassica species. Utilization of molecular breeding tools has been a great advantage in B. oleracea vegetable breeding around the world. Construction of genetic maps based on molecular markers ranging from isozyme to single nucleotide polymorphism (SNP) markers has enabled mapping of various important genes and quantitative trait loci (QTL) for yield, quality, disease resistance, and earliness in B. oleracea. This chapter focused on milestones in the utilization of various genomics tools such as genetic map construction, gene and QTL (fine) mapping, molecular marker development and marker-assisted selection in B. oleracea vegetable crops for enhancing productivity, quality, and yield to meet ever increasing vegetable demand. Use of genetic resources such as male sterile systems, restoration of male sterility for hybrid seed production and exploration of heterosis in hybrid Brassica vegetable breeding is also discussed.