Effects of Global Warming Simulated Temperature and Water Stress on Fruit Quality of Tomato (Lycopersicum esculantum) Var. Rajitha

Experiments were conducted in the temperature regulated poly-tunnels for five consecutive growing seasons at the Open University of Sri Lanka to evaluate the impact of the enhanced temperature and water stress due to Global warming on marketable fruit quality. Split plot experiment based on complete randomized design with 10 replicates was applied as experimental design. The plants were grown in pots, and the main plot included two moisture levels (No water stress, 50% water stress from the field capacity) and sub plots contained 3 different temperature regimes (34°C maximum temperature / 32°C maximum temperature / ambient temperature). Experiments were repeated for 3 seasons to replicate temperature effect. The combination effect of water stress and temperature stress proved to be a significant drawback for tomato yield and marketable fruit quality such as colour, shape, soluble solids content, pH and sugar acid ratio. Mealy bug attack too was very significant in high temperature poly tunnel experiment which affected the marketable fruit quality. Therefore, tomato variety Rajitha could not be a successful open field crop in the dry zone of Sri Lanka if temperature is increased due to global warming. But tomato could be cultivated under green houses by providing adequate water and required soil temperature.