Action evaluation of a virus on yield and quality of sweet potato tubers

ABSTRACT The Western region of São Paulo State, Brazil, is responsible for approximately 40% of the production of sweet potato (Ipomoea batatas L.) in the state, even under low-technology. The study aimed to evaluate the impact of viruses on sweet potato production variables. The experiment was conducted in Presidente Prudente, São Paulo, Brazil, in a commercial sweet potato crop of pink group, cv. Canadense, with and without virus. In three randomly chosen plots of 10 x 4 m in each half of the field (with and without virus), ten central plants were randomly collected. The number, weight, length and diameter were evaluated. The plots without virus produced 50% more tubers and 100% more weight during harvesting. Tubers obtained from virus-free seedlings showed a greater mass (p < 0.01), height (p < 0.01) and mean diameter (p < 0.05) than those harvested from infected plants. From free-of-virus seedlings, 65% of tubers were classified as 2A (150 to 299 g), the standard that represents 70% of the trading volume at a Food Market place, which provides greater profitability to the producer.