Chinese kale and Caisin are two of the main leafy vegetable
crops grown in south-east Asian countries, especially in
Thailand (Sagwansupyakorn, 1994). These two Brassica
species originated in China, however, different cultivars of
them can be grown successfully in a wide range of climatic
conditions including cool winters, warm summers and even the
hot and humid conditions experienced in the south of Thailand
(latitude 88N).