Brassicaceae
family(Brassica campestris)
Brassicaceae
family
The Chinese cabbages, bok choy (left-var. chinensis) and napa or pai-tsai (right-var. pekinensis), are closely related to the turnip. Their chromosome number is 2n=20, and they carry the Brassica AA genomes. They were first cultivated as vegetables in China, first appearing in Chinese writings by A.D. 400 or 500. They are grown as annuals and are a cool-season crop usually cultivated in the fall due to their sensitivity to flowering-induction under 15-16 hour days.