Impact of Temperature and Water Stress on Growth Yield and Related Biochemical Parameters of Okra

Abstract

The main aim of this research is to compare the physical and biochemical parameters of okra when subjected to heat and water stress and to determine how heat shock or water deficit, either individually or in combination, affect the growth and yield of okra species. Experiments were conducted in three growing seasons in the low country wet zone as a replicated trial. The plants were grown in pots under temperature-controlled polytunnels. Main plot included two different wetting applications (no water stress, 50 % water stress from the field capacity) and sub plots contained 3 different temperature regimes (34 °C maximum temperature polytunnel / 32 °C maximum temperature polytunnel / ambient temperature). Individual water stress showed highly significant effect on growth, and yield parameters of okra. High yield reduction was shown in the water stressed plants. Further temperature stress has especially affected the pod quality parameters such as fibre and pectin content. Harvesting time of okra under ambient temperature was not suitable for the high temperature conditions due to rapid pod growth rate and break down of the calcium pectate, 5 to 6 days after full blooming. Results indicated that okra has high yield when it is grown under high temperature environment with no water stress. Therefore by maintaining irrigation at field capacity level even at high temperature stress conditions, it is possible to achieve a good yield by harvesting okra pods 5 to 6 days after full blooming without significant yield reduction. Tropical Agricultural Research Vol. 23 (1): 77-83 (2011) DOI: http://dx.doi.org/10.4038/tar.v23i1.4634