Prediction of Seed Regeneration time of Some Medicinal Plants by Estimation of Viability equation Constants

One of the most common methods for conservation of plant genetic resources is their ex situ storage as seed gene banks. Seeds that are stored in the gene banks must be regenerated due to exchange and seed deterioration; if they not be regenerated the potential benefits of infrastructure investments for germplasm ex situ conservation may not be attained. Prediction of seed longevity is based on viability equation that has four constants which are species specific. The aim of this project was estimation of these constants and then using them for predicting the regeneration time of Thymus transcaspicus،T. daenensis،Salvia officinalis، Satureja hortensis، Dracocephalum moldavica، Descurainia sophia،Eruca sativa andMelilotus officinalis. The seeds were placed in three environments with relative humidity of 20، 40 and 60% and their moisture content was measured after equilibrium. Then the seeds sealed in nylon pockets and stored at 30، 35 and 40 ºC. The TP germination tests with three replications were done monthly. The Excel software was used for estimation of viability constants (i. e. KE، Cw، CH، CQ). The KE was estimated 5. 065، 5، 5، 4. 46، 3. 837، 4. 33 and 4. 21 for T. transcaspicus، T. daenensis، Salvia officinalis، Satureja hortensis، Dracocephalum moldavica، Descurainia sophia، Eruca sativa and Melilotus officinalis respectively. The maximum and minimum seed longevity estimated for T. transcaspicus and Eruca sativa respectively. If viability be 100% at the beginning of the storage، the seeds of T. transcaspicus and E. sativa with 8% moisture content in the active collection (5 ºC) must be regenerated after 123 and 15 years respectively.