The Combined Effect of Salinity and High Temperature on Winter Wheat at Booting.

The combined stress of salinity and high temperature is one of the major environmental factors that limit wheat (Triticum aestivum L.) productivity. As the world population increasing, and water resources for the cropping decreases and temperature increases, thus identification of genotypes tolerant to salinity and high temperature is critical for yield improvement. The objective of this study was to evaluate the effects of combined stress (salinity and high temperatures) during booting stage on growth and yield characters of winter wheat genotypes. Twelve genotypes of winter wheat were grown in non-saline medium and at optimum temperatures (25/15 °C day/night) until booting. At booting, plants were irrigated with three different salinity levels (0. 60. 120 mM NaCl and exposed to optimum and high temperature (25/ 15 °C day/ night and 35/ 20 °C day/night) for 10 days. High temperature stress, when combined with salinity during booting stage, negatively affecting the growth and development of plant and resulting in lower plant productivity. Greater impact on yield was observed at the combined stress compared with salinity alone and/or high temperature alone. The study found that salinity and high temperature treatments, decreased leaf level photosynthesis, seed set, grain number and grain yield per spike. In addition, the study showed considerable variation in high temperature and salinity tolerance among winter wheat genotypes for leaf level photosynthesis, seed set, grain number and grain yield.