The genus Brassica includes many economically important crops providing nutrition as well as health-promoting substances. Most cultivars of the Brassica vegetables are F1 hybrids, and breeding system was successfully established by effectively applying the phenomenon of heterosis or self-incompatibility. However, their production is constantly threatened by abiotic and biotic stresses such as the increasing numbers of races and isolates of pathogens, inappropriate cropping systems, and changing climate. Traditional methods of control are often costly and environmentally damaging, while the ideal way is to mine and use the abiotic or biotic resistance from the crop hosts. Fortunately, genomics and molecular genetics enables the rapid discover and application of plant breeding to improve adaptation to environmental conditions and abiotic or biotic resistance. Herein, we have summarized the important characteristics for breeding of the Brassica vegetables, including the trials for understanding the molecular mechanisms with genetic and epigenetic approaches. Some future perspectives are also given concerning how to efficiently use these genes and overcome global climate change.