Assessment Of Natural Ageing Related Physio-Biochemical Changes In Onion Seed

This research was performed for a period of three years to determine the effect of natural seed ageing on different physiological and biochemical changes in three extensively cultivated onion cultivars in Northern India. Seed storage studies showed that germination percent, seed viability and other seed quality parameters decreased significantly with increasing storage time. The onion seed can be stored for a maximum period of one year under ambient conditions to maintain required germination percentage (>70%). Overall, Hisar Onion-4 stored better when compared to Hisar Onion-3 and Hisar-2. As the ageing progressed the seed antioxidants, namely superoxide dismutase (SOD), catalase (CAT), dehydrogenase (DHA) and peroxidase (POD) decreased significantly (p < 0.05) in all cultivars whereas, the electrical conductivity (EC) of seed leachates increased significantly. Under the field conditions, seedling establishment percent (SE) onion seed was positively correlated (R-2 = 0.98; p < 0.05) with germination percent (GP). Overall, more than one year period of seed storage was associated with poor germination and seedling establishment potential in onion.