Planting density using mini-cutting seedlings: Effects on root and starch production of sweet potato

ABSTRACT Traditional propagation of sweet potatoes using vines increases the transmission of pathogens in the crop. Using pathogen-free mini-cutting seedlings is a promising alternative, but it provides lower root production per plant. Adjusting the planting density can optimize this technique and compensate for the lower individual production of plants. This study aimed to determine the optimal planting density for maximizing storage root yield and quality of sweet potatoes propagated by mini-cutting seedlings. The experimental design was of randomized blocks with four treatments and five replications. The treatments were represented by planting densities of 25,000; 33,333; 41,667, and 50,000 plants/ha, with a row spacing of 1.20 m. The study demonstrated that increasing the planting density to 40,258 plants/ha increased total root yield by 24%, while starch yield increased by 17% up to a density of 41,624 plants/ha. Higher planting densities favored the production of roots of all sizes, including those of greater marketable value. However, to maximize the production of large and medium-sized roots, densities between 36,420 and 50,000 plants/ha are recommended. Although high densities may result in a small reduction of 7% in the root mean weight, the use of mini-cutting seedlings does not compromise root yield and quality, as long as the ideal planting density is adopted.