To evaluate the effect of low temperature and calcium carbide on the emergence of yam tuber-seeds, Da Costa cv., an experiment was carried out from October, 1998 to March, 1999, in Areia, Brazil. To evaluate the influence of the low temperature on the emergence of yam tuber-seeds, tubers were stored in cold chamber at 5ºC and relative humidity of 90% in four periods (10; 15; 20 and 25 days). To evaluate the efficiency of the calcium carbide on breaking dormancy of tubers, the same were conditioned in black polyethylene bags with calcium carbide in the proportion of 60 g/kg of roots and stored under conditions of open shed (temperature of 27ºC and humidity of 64%), in four periods (10; 15; 20 and 25 days). As control there were used tubers conditioned in bags of black polyethylene without calcium carbide and stored in open shed. Afterwards, tubers were planted in beds, to evaluate plant emergence. The experiment was laid out in complete randomized blocks with ten treatments and four replications. The experimental unit was constituted of 20 tuber-seeds. The low temperature didn't induce the emergence of yam tuber-seeds in any storage period, and at 25 days, tubers were rotten. At 40 days after planting date, higher emergence occurred in tubers stored in polyethylene bags containing calcium carbide during ten to fifteen days; this increase was of 35% in the number of emerged plants in relation to the tuber-seeds conditioned in bags without calcium carbide and of 38% in relation to the tuber-seeds stored under environmental conditions
Dioscorea cayennensis Lam; dormancy
