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.