Abstract

In a laboratory, experiment germination characteristics and seed reserves mobilization of wheat cultivars were evaluated at three temperature regimes (16, 26 and 36°C). Four heat tolerant cultivars (Gourab, Sourav, Kanchan and Shatabdi) and two heat sensitive cultivars (Sonora and Kalyansona) were used as study materials. Germination characteristics expressed as rate of germination, coefficient of germination and germination vigor index, increased with an increase in temperature. The shoot dry weight and shoot to root dry weight ratio, increased with increasing temperature. But in root dry weight, the highest values were found to be 26°C compared to 16 and 36°C temperature. The dry matter distributed in shoot and the respiratory loss, increased with increasing temperature in all the cultivars. But these increments were greater at 16 - 26°C than those at 26 - 36°C. Therefore, temperature had a profound effect on seed metabolic efficiency (SME). At moderate temperature (26°C), all the cultivars showed the highest SME than the lowest (16°C) and highest temperatures (36°C). Heat tolerant cultivars attained higher SME (2.55 - 2.88 g/g) than those of heat sensitive cultivars (Sonora and Kalyansona) (2.00 - 2.1 g/g).

Key words: Wheat, temperature, germination, seed metabolic efficiency.