Prediction of seed longevity in the genebank: How reliable are the estimates?

Abstract

Germplasms of crop plants are stored as seeds in genebanks at low temperature with low seed moisture content where they remain viable for several decades. The longevity of seeds stored in genebanks is predicted using viability equations developed by subjecting seeds to accelerated ageing under controlled laboratory conditions. We discuss here the serious consequences of provisionally or unreliably developed estimates of seed longevity parameters in making such predictions. A slight under or over estimation to the tune of 0.01 of the linear temperature parameter may result in a difference ranging from 46 to 74 years in the expected longevity. Whereas in case of the quadratic temperature parameter, a minor estimation difference (0.0001) may cause a difference of 11 to 12 years. A nonlinear estimation method based on Levenberg-Marquardt iterative convergence algorithm was applied for the reliable estimation of viability parameters for Lupinus polyphyllus seeds. The said estimation procedure resulted into comparatively narrow confidence intervals; and almost four to five times gain in precision over the conventional linear estimation in estimating potential longevity and moisture sensitivity parameters.