This study was carried out in two steps at UFPB, in Areia, Paraiba state, Brazil, to evaluate the yam seed production by a high density planting system of tuber-seed portions and its effect on tuber yield. The experimental design in the two steps was randomized blocks with eight treatments and four replications. In the first step were produced yam tuber-seeds through planting of tuber-seed. Initially, we produced tuber-seed portions by planting pieces of 25, 50, 75, 100, 125, 150, 175 and 200 g, spaced 20 x 20 cm. The seeds produced in the previous step, had average weight of 108, 133, 157, 181, 205, 229, 253 and 277 g, which were planted to evaluate the yam yield. We evaluated the average mass and the production of seed tubers and the total and commercial yield. The production and average weight of tuber-seeds increased linearly with increasing weight of the pieces of tuber-seeds planted, with maximum values of 277 and 4,170 g, respectively, obtained with a piece of 200 g of tuber-seeds. The total average yield was 13.6 t ha-1 depending on the weight of the planted seed-roots. The marketable yield of tubers was 10.8 t ha-1 obtained with tuber-seeds with an average weight of 181 g, which represents a savings of 34% in the amount of tuber-seeds necessary for the implementation of a hectare of yam.
Dioscorea cayennensis; tubers-seed; planting density; tubers production
