Comparative assessment of onion seed longevity under ambient storage and artificial ageing conditions

A study was carried out to assess the storage potential of onion genotypes under natural as well as accelerated ageing conditions. Freshly harveted seeds of thirty onion genotypes were subjected to nine months of natural ageing as well as accelerated ageing for 3 and 6 days (42oC and 75% RH). Significant effects of seed ageing on germination percent, seed vigour index, mean germination time and germination index were recorded. Germination percent ranged from 56.0- 96.0 percent in unaged seeds, which declined to 31.0-82.0 and 18.0-83.0 percent respectively after natural (9 months) and accelerated ageing treatments (6 days). In the current study, the seed germination and vigour indices decreased significantly, whereas the mean germination time increased for all the genotypes under both ageing treatments. Further, cluster analysis was utilized to categorize the onion genotypes into good or poorer storers. A significant and positive correlation was found among both natural as well as artificial ageing treatments. The study facilitated the categorization of onion genotypes into distinct storage groups by evaluating their performance under both natural as well as accelerated ageing.