Determinatión of Optímum Harvesting Time for Okra (Abelmoscus Esculentus Var. Haritha) to Cope with Temperatura and Water Stress Pue to Global Warming

Abstract

The aim of this study is to compare the physical and biochemical parameters o f Okra when subjected to heat and water stress and to determine the optimum harvesting time as an adaptalion to global warming. Experiments were conducted in three growing seasons in the low country wet zone as a replicaied trial. The plants were grown in pots under lemperature-controlled poly tunnels. Main plolincluded two different wetting applications (No water stress and 50% water stress from the field capacity) and sub plots contained 3 different temperature regimes (34 °C maximum temperature poly lunnel /3 2 °C maximum temperature poly tunnel / ambient temperature). Individual water stress showed highly significant effect on growth, and yield parameters of Okra. High yield reduction has showed in the water stressed plants.. Further temperaiure stress has especial|y affected the pod quality parameters such as fibre and pectin content. Therefore the optimum time of harvesting of Okra in days after full bloom under ambient temperature is 10 whereas in the temperature stress conditions its varied. Accordingly the optimum harvesting time in 32°C and 34°C will be 7- 8 days and 5-6 days after full bloom when plants are not subjected to water stress. Results also showed that Okra has 27% higher yield than ambient temperature, 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 7 days after full blooming.