Variation of wheat cultivars in their relationship between seed reserve utilization and leaf temperature under elevated temperature

Abstract

An investigation on physiological changes was carried out in three wheat genotypes (BARI Gom 25, BARI Gom 26, and Pavon 76) through seed reserve utilization efficiency (SRUE) and leaf cooling under normal (15 / 25°C) and elevated (25 / 35°C) temperatures in the growth chamber. At high temperature, Pavon 76 required more days to initiate the fully autotrophic stage. After germination, seedling and remnant seed dry weight was the same at day 5 in BARI Gom 26 and day 6 in BARI Gom 25 and Pavon 76. At high temperature, maximum translocation efficiency and seed reserve utilization efficiency (SRUE) were observed in BARI Gom 26 and at a minimum value in Pavon 76. High leaf cooling was recorded in BARI Gom 26. At high temperature, due to high leaf temperature and low transpiration rate of Pavon 76, maximum reduction of seedling growth was recorded in Pavon 76 (17%) as compared to minimum in BARI Gom 26 (5%). It appeared from the result that at high temperature the better seed reserved utilization efficiency and subsequently larger leaf cooling collectively contributed a positive role for seedling development in BARI Gom 25 and BARI Gom 26. The relationship of seed reserve utilization efficiency and leaf temperature were prominent in the case of Pavon 76 (r = -0.768) compared to other genotypes. This relationship indicated that Pavon 76 was the most sensitive genotype and BARI Gom 25 and BARI Gom 26 was the tolerant genotype to heat stress in respect to seed reserve utilization efficiency during seed reserve dependent phase and leaf temperature of photosynthetic-dependent phase.