Effect of ultra-drying on storability and vigour of onion seeds

Abstract

Onion seeds are poor storers they have one of the lowest storability among cultivated crops. Seed moisture is one of the critical factors which determines the seed storability. The effect of ultra-drying of onion seeds on seed storability and seed vigour was studied. Seeds of three onion varieties Bhima Dark Red, Bhima Shakti and Bhima Safed were dried in 2:1 beads to seed ratio (w/w) for 96 hours and packed and stored in moisture impervious pack for 12 months under ambient conditions. The initial moisture of seeds was 8.46% - 5.25%, which reduced to 3.48 - 2.91% at after 96 hours. The ultra-dried seeds had higher seed viability and vigour in comparison to control (undried seeds). At the end of 12 months of storage, the average seed germination in ultradried seeds was 81% whereas in control it was 52%. In comparison to control at the end of 12 months, the ultradried seeds had 23.82%, 33.80%, 83.12% and 98.60% higher seedling length, seedling dry weight, vigour index-I and vigour index-II. The ultra-dried seeds also recorded lower electrical conductivity indicating lower membrane degradation during storage. Thus, drying of onion seed in 2:1 beads to seed ratio for 96 hours is beneficial in enhancing the storability of onion seeds.