Abstract
The effects of temperature and water stress on agronomic and physiological characteristics were studied in heat-tolerant tomato cultivar TM 0126. Water stress significantly reduced yield, flower number, fruit weight, fruit number, pollen germination percentage, and shoot and root dry weight. High temperature (HT, 30/25°C day/night) significantly reduced yield, pollen germination percentage, shoot and root dry weight. No statistical interaction between the effect of water stress and temperature regimes was observed for yield, yield components, pollen germination percentage, shoot and root dry weight. A more pronounced decrease in the photosynthetic rate (Pr) by the water stress treatment was detected under HT than under MT (moderate temperature regime, 23/18°C day/night), but after re-watering a more rapid increase of Pr was observed under HT than under MT. A similar tendency was found in the effect of water stress on the transpiration rate (Tr) . Stomatal resistance (Rs) was significantly higher under HT than under MT, but the increase by water stress was more remarkable under MT than under HT. Leaf water potential (Ψ1) was significantly reduced by the water stress treatment under both temperature regimes. The absence of interaction between water stress and temperature for some agronomic characteristics of this cultivar may be caused by the rapid recovery of physiological characteristics after re-watering. Mechanism of drought and high temperature tolerance of TM 0126 was discussed.
