EFFECT OF STORAGE-SYSTEM AND SPROUT REMOVAL ON POSTHARVEST YAM (DIOSCOREA SPP.) FRESH WEIGHT LOSSES

Two aspects of yam storage practice were tested from 1994 to 1995 in c entral Cote d'Ivoire. The first experiment compared the storage enviro nment in pits or sheds with that of the traditional yam open barn meth od. The pits allowed the daily range of variation in temperature to be reduced while maintaining a high relative humidity (RH), whereas the temperature and RH in the sheds were similar to those of the yam barns . Differences in temperature and RH between the storage systems had li ttle effect on the fresh weight losses of the tubers. The more effecti ve protection against solar radiation and rain afforded by the sheds a nd pits reduced fresh weight losses in D. cayenensis rotundata by 12% over 6.5 months in comparison with the barns. The second experiment te sted the regular removal of the sprouts. Sprout removal reduced fresh weight losses equally over 5 and 6 months' storage. The reduction in f resh weight loss was 12% for cv. Gnan (D. cayenensis rotundata) during 6 months' storage. Monthly sprout removal gave an equal benefit in pi ts, in sheds and on yam barns. The monthly cutting of sprouts at the b ase should be encouraged in places where this is not already done. The total loss is mainly determined by the growth of the sprouts and the reduction in weight after onset of sprouting, which are highly depende nt on species and cultivar. Bete bete yams had better keeping qualitie s than all the other cultivars tested.