Improved longevity of onion ( Allium cepa L.) seeds by immersing in hexylene glycol

Abstract

Onion ( Allium cepa L. cv. ‘Arka Niketan’) seeds with different moisture contents were sealed hermetically or immersed in liquid desiccants, i.e. ethylene glycol, propylene glycol, glycerol, diethylene glycol, hexylene glycol and triethanolamine and stored at ambient temperature. Viability and vigour in the seeds were monitored during storage. The seeds stored hermetically at 10% moisture content (MC, fresh weight basis) lost viability completely in about 300 days. The seeds immersed in the liquid desiccants except those in hexylene glycol, imbibed the chemicals and lost viability completely in a period of about 1–4 years. There was no loss of viability in the seeds immersed in hexylene glycol for 1100 days. However, some loss of viability and substantial loss of vigour in terms of reduction in growth of seedlings was detected subsequent to storage for 1460 days. The seeds hermetically stored at 8% MC lost viability in about 1100 days. The seeds with 2% MC stored hermetically or immersed in hexylene glycol did not show apparent loss of viability even after 1460 days storage, though a slight loss of seed vigour as evidenced by decline in growth of seedlings was shown by the seeds immersed in the hexylene glycol. The longevity of undried seeds immersed in hexylene glycol was intermediate between that of seeds with 8% and 2% MC both hermetically stored. The results suggest preservation of onion seeds in hexylene glycol as a simple and cost effective method for improving short- or mediumterm longevity at ambient temperature.