Experimental Analysis of Yam (D. Spp) Tuber Stability in Tropical Storages

ABSTRACT AN experimental investigation, using 180 D. rotundata tubers, was conducted to determine the stability of the yam tubers in three storage structures. The structures used were a traditional yam barn, an underground pit with a chimney attachment (Pit 1) and an underground pit without a chimney (Pit 2). Air temperatures varied from 21 °C to 26°C with a mean of about 25°C in Pit 1, from 23°C to 28°C with a mean of 27°C in Pit 2, and from 24°C to 37°C with a mean of 35°C in the barn. The relative humidities attained in these structures were of the order of 90%, 83% and 60% respectively. Tubers stored in the well ventilated pit 1, sustained a weight loss of 15 to 25% in 5 months. Sprouting in this structure was not initiated until the 12th week and the sprouting index, defined as the number of sprouted tubers divided by the total number of tubers, was only 43% in 16 weeks. On the other hand, a weight loss of up to 60% in 5 months was attained in the yam barn where 100% sprouting occured in 10 weeks of storage- These results will be useful in making engineering specifications for the storage conditions for intact yam tubers.