Abstract
The effects of sudden and gradual water stress on the growth and yield of two cultivars of chilli pepper, Huay Siithon (HS) and Yatsubusa (YB), were investigated. Sudden water stress was imposed by completely withholding water, while gradual one by supplying about 75%, 50% and 25% of the amount of water which was supplied to the control plants in the first week, second week and the next 10 days, respectively. Thereafter no water was supplied to the plants until rewatering in this treatment. Plants in both treatments were rewatered when severe wilting persisted throughout the night.
The harvesting dates for both cultivars were delayed due to the stress, while the delay was less pronounced in the plants subjected to sudden-stress (SS plants) than in the plants subjected to gradual-stress (GS plants) . The more pronounced decrease in the fruit weight, mature fruit yield and total yield in the GS plants of both cultivars than those in the SS plants indicates that the gradual and long-term water stress affected growth and yield more adversely than the sudden and short-term water stress. The reduction in the mature fruit and total yield in both stress treatments in YB was much greater than in HS. The absence of the decrease or small decrease in the shoot and root dry weight of the stressed plants were attributed to the immediate recovery of the vegetative growth which may have taken place after stress removal.
