The influence of storage conditions on seed viability

So far as is known, all pasture and forage legumes show orthodox seed behaviour: that is over a wide range of storage conditions longevity increases with decrease in moisture content and decrease in temperature in a predictable manner. Although the patterns of loss of viability are similar for all orthodox seeds, for any given set of storage conditions different species may show considerable differences in longevity. Legume seeds in general store well. Ex situ conservation of forage and pasture legumes should therefore present few serious problems providing accessions are of initial good quality and are then stored under the conditions recommended by FAO and the International Plant Genetic Resources Institute, viz. at 3–7% moisture content (depending on species) and at — 18°C or less. Under such conditions it should not be necessary to regenerate stocks for a century or more. If the accessions are of poor quality (initial low viability), or if inferior storage conditions are used, then not only may viability drop sooner to unacceptable levels but there may also be some genetic alteration due to genetic selection within accessions and an accumulation of mutations.