Effect of Water Stress at Various Stages of Plant Development on Growth and Yield of Chilli Pepper

Abstract

Four cultivars of chilli pepper (Capsicum annuum L.) obtained from different regions were investigated for the effects of water stress applied at various stages of development on their growth and yield. In a plastic greenhouse, the stress treatment was applied at the seedling and mature stages by withholding water supply, and rewatering when severe wilting symptoms persisted throughout the night. Mature stages were divided into three 10-day intervals, namely pre-anthesis, anthesis and post-anthesis stages. All the cultivars were able to tolerate the stress for almost the same period of time at the same treatment stage, but the plants treated at the seedling stage were able to tolerate the stress for a longer period of time. This phenomenon may be ascribed to the fact that the water loss of the plants treated at the seedling stage was lower than that of the plants treated at the mature stages. Plant growth and yield were more appreciably affected by stress at the seedling stage than at the mature stages in all the cultivars. This observation suggests that prolonged and gradual stress at the seedling stage suppressed the growth and yield more significantly than brief and rapid stress at the mature stages. Huay Siithon (HS) was less affected than Deshi Morich (DM), which belongs to the same variety conoides as HS, while Yatsubusa (YB) was more affected than Khonkaen University cluster (KC), which belongs to the same variety fasciculatum as YB, especially in the mature fruit yield. These observations suggest that the genetic background acquired through adaptation to natural conditions may influence the differences in the plant responses to water stress.