Evaluation of germination and some biochemical indices of faba bean (Vicia faba L.) seeds stored at different temperatures and moisture content

This study was performed to investigate the effect of storage conditions on seed germination performance of faba bean (cv. Shami). For this purpose, a three factors factorial experiment was conducted in laboratory of Seed Science and Technology, Faculty of Agriculture, Yasouj University, in 2013-2014, based on CRD design with five replications.  The experimental factors were storage temperature (15, 25, 35 and 45 °C), seed moisture content (6, 10, 14, 18 and 22 percent) and storage duration (0, 30, 60, 90, 120, 150, 180, 210, 240 and 270 days). Also, in order to study some biochemical characteristics, 5 storage durations (0, 30, 90, 180 and 270 days of storage) were selected. Results showed that during storage, germination percentage, seedling length, seedling dry weight and seedling vigor index responded to temperature and seed moisture content (SMC), that is by increasing the moisture content of seeds at each temperature, germination percentage reduced (5-100%) and electrolyte leakage (60 to 370%) increased. At temperatures of 15 and 25 °C at moisture contents of 6, 10 and 14%, the seed deterioration rate was low while was fast (more than twice) at moisture levels of 18 and 22%. However, at 35 and 45 °C, the rate of seed deterioration, increased storage moisture content of 10 %, so that at SMC of 22 %, germination and seedling growth dropped to the lowest levels (zero) after 30 days of storage. Soluble protein content and catalase activity also decreased with during storage period. Reduction of antioxidant enzymes activity and increase of free radical damage were found as main reasons for the decline of faba bean seed viability during storage at high temperatures and high seed moisture content. Seed moisture contents of 6, 10 and 14% at temperatures of 15 °C and 25 °C are recommended for long-term storage of faba bean seeds.