Variation in adaptation to drought within the Brassica genus
is more widely observed with Brassica juncea showing
tolerance and B. napus being more susceptible to dry
conditions. However, variation in sensitivity to drought is
present within B. napus and B. juncea (Niknam et al., 2003). In
southern Thailand, leafy vegetables are grown where rainfall
may be excessive or deficient and tolerance of both these
conditions is needed for high productivity.