Leafy vegetables are expected to grow where
there is an adequate water supply and the soil is well drained. In
Thailand, rainfall varies dramatically from season to season and
from place to place. In the same year, some areas experience
flooding while on the other hand some areas experience long
periods of drought. The responses of plants to waterlogging and
drought are widely reported (Blum, 1996; Freitas, 1997; Arteca,
1997; Huang, 2000a) but less is known about the response of
Brassica species, especially leafy vegetables. There is variation
within the Brassica genus in the response of species to
waterlogging, including Brassica rapa (Ashraf and Mehmood,