A suitable liquid preservative for enhancing longevity of orthodox seeds

Abstract

Onion ( Allium cepa L. cultivar ‘Arka Niketan’) seeds with different moisture contents were sealed hermetically or immersed in a liquid preparation consisting of 25% (w/w) CaCl 2 in glycerol (CALGLY) and stored at ambient temperature. Seeds with an initial germination of 96% when hermetically stored at 10% and 8% moisture content (MC, fresh weight basis) lost viability completely in about 300 and 1100 days, respectively. The seeds that were hermetically stored at 2% MC, and those at 10% and 2% MC immersed in CALGLY did not show any loss of viability after 2190 days, although some loss of vigour was apparent as shown by a detectable reduction in seedling growth. Thus, the improvement in longevity of onion seeds obtained by immersing in CALGLY was equivalent to that obtained with the seeds hermetically stored at 2% MC. Immersing seeds at 2% MC in CALGLY did not improve their vigour over seeds hermetically stored at a similar moisture content, but immersing in the liquid preparation improved the vigour and viability of the seeds stored at 10% MC. These findings provide evidence that CALGLY improved longevity of the onion seeds at 10% MC probably by ultradrying them to about 2% MC. CALGLY similarly improved the longevity of other representative orthodox seeds, viz. capsicum ( Capsicum annum L. var. ‘Arka Gauraw’), chilli ( Capsicum annum L. var. ‘Arka Lohit’), carrot ( Daucus carota L. var. Nantes), and pea ( Pisum sativum L. var. ‘HUP’) over the seeds with similar moisture contents in hermetic storage, at ambient temperature. Storing seeds by immersion in CALGLY is a simple and cost-effective method for enhancing medium- or long-term longevity of orthodox seeds at ambient temperature.