A laboratory experiment was conducted in the Crop Botany Laboratory , a t Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur during 15 October to 15 November, 2001 to study the influence of three temperature regimes (15OC, 25OC and 35OC) on germination characters and seed reserve qobilization in six wheat genotypes. Three heat tolerant ( Aghrani, Kanchan and CB-30) and three heat sensitive (Sonora, CB-24 and CB-34) wheat genotypes were used as study material. Speed of

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... ination expressed a s rate of germination, coefficient of germination and germination vigor index was found to be increased with increasing temperature from 15 O C to 35OC in all wheat genotypes, but heat tolerant ability based on speed of germination was not found. Generally shoot and root growth of HS genotype in relation to length and dry weight were affected more than those of HT genotypes a t high temperature. The amount of seed reserve loss a s respiration increased from 25OC to 35OC in all genotypes, but the increment was higher in Sonora (14.1%) and CB-24 (13.21%), moderate in Kanchan (6.36%), CB-30 (5.22%) and CB-34 (4.95%) and lowest in Aghrani (2.03%). At 15OC, the amount of seed reserve loss a s respiration was also increased from that a t 25°C in all genotypes except in Aghrani and CB-30. But again the increment was higher in Sonora, CB-24 and CB-34 (2.79 to 8.84%) than that of Kanchan (1.67). In case of ~~h r a n i and CB-30, it even decreased. At 25OC temperature the seed reserve mobilization efficiency was significantly higher than that a t 15OC and 35OC in all wheat genotypes. But the heat sensitive genotypes had higher efficiency (2.58 to 3.48 glg) than that of the heat tolerant genotypes (1.99 to 2.09 gig) a t 25OC. Based on reduction of efficiency both a t 15OC and 35OC from that of 25OC, Sonora, CB-24 and CB-34 (HS) were found more affected than Aghrani, Kanchan and CB-30 (HT).