Estimation of seed viability constants for tall wheatgrass, cocksfoot, rye, and sheep fescue to inform gene banking decisions. Hamid Reza Eisvand

Stored seeds deteriorate over time and must be regenerated to ensure that the benefits of ex situ conservation are realized. Prediction of seed longevity is based on the seed viability equation. This equation has four constants which are species specific. The aim of this project is the estimation of these constants and prediction of regeneration frequency for Elytrigia elongata, Dactylis glomerata,Festuca ovina, Secale cereal, andSecale montanum. Seeds were equilibrated at 20, 40, and 60% RH and their moisture content was determined after equilibration. Seeds were then sealed in nylon pockets and stored at 30, 35, and 40° C. Germination was tested monthly. Seed viability constants (KE , Cw , CH, CQ) were estimated and regeneration time was calculated for each species. High variation in seed longevity was observed both among the genus and species. Elytrigia elongata with KE=6 and Cw=1.64 had the maximum seed longevity of all species evaluated; seeds stored in an active collection (8% mc, 5° C) would have to be regenerated after 131 years. The minimum seed longevity was obtained for Festuca ovina with KE=4.3 and Cw=0.5; seeds stored in active collections would have to be regenerated after 33 years.