West African yam seeds stored under desiccated and cold storage conditionsare orthodox

The longevity of botanical seeds of a West African yam species, Dioscorea r otundata Poir. cv. Obiaoturugo, was determined under a number of dry-cold s torage conditions to preserve yam genetic resources. Seeds were dried to 14 .5%, 10.1%, and 5.0% seed moisture content and stored at -20 degrees C, 5 d egrees C, 15 degrees C and 25 degrees C for three years. The half-life (P-5 0) values derived by probit analysis of viability decline curves during sto rage of seeds for 12 dry-cold storage treatment combinations suggest that s eed longevity can be prolonged by desiccation and cold storage. The highest seed storage life of 21 years was derived for seeds dried to 5% moisture c ontent and stored at -20 degrees C. This was followed by 19 years with the seeds dried to 5% moisture content and stored at 5 degrees C. The shortest seed storage life of about seven years was estimated for seeds of 14.5% moi sture content at 25 degrees C. Results showed that the storage of seed usin g the conventional dry-cold gene bank conditions offer good potential for l ong-term yam germplasm maintenance.