Effect of Air and Root-zone Temperatures on Physiological Characteristics and Yield of Heat-tolerant and Non Heat-tolerant Tomato Cultivars

Abstract

Comparative studies on photosynthesis (P_r), transpiration (E), stomatal conductance (G_s), and yield of heat-tolerant tomato (Lycopersicon esculentum Mill. cv. Shuki) and non heat-tolerant one (cv. Sataan) at 2 air (40°/23° and 22°/16°C) and 4 root (15°, 20°, 25°and 30°±0.5°C) temperatures were carried out. Physiological characters were measured at the vegetative, flowering and fruiting stages of growth. P_r, E and G_s of 'Shuki' at high air and root-zone temperatures were significantly higher than those of 'Sataan' at the seedling, flowering and fruiting stages but no significant differences were observed at low air temperatures. Yield of 'Shuki' was significantly higher than that of 'Sataan' at all root-zone and high air temperatures but not at low air temperatures. Yield correlated significantly with photosynthesis at high air temperatures but no correlation was observed at low air temperatures.