AGRONOMIC PERFORMANCE OF SELECTED SWEET POTATO CULTIVARS UNDER GREENHOUSE AND FIELD INFESTED WITH MELOIDOGYNE INCOGNITA AND SOILBORNE INSECT PESTS

The root knot nematode (RKN), Meloidogyne incognita, is widespread worldwide and a major pathogen of several cultivated crops. The use of resistant genotypes is the most effective and environmentally sound way to manage RKN. In this study, we screened 16 selected sweet potato cultivars including Amanda, Barbara, Beatriz, Beauregard, Brazlandia Branca, Brazlandia Rosada, Brazlandia Roxa, BRS Amelia, BRS Cuia, BRS Rubissol, Carolina Vitoria, Duda, Julia, Marcela, PA-26/2009, and Princesa obtained from Embrapa and Universidade Federal do Tocantins' germplasm bank. Studies were conducted under greenhouse and field conditions and the agronomic performance of the cultivars was evaluated in a nematode and soilborne insect-infested field. All 16 sweet potato cultivars tested were rated as resistant to this nematode both under greenhouse and field conditions with reproduction factors < 1. In the field infested with M. incognita, sweet potato cultivars Duda, BRS Amelia, Beauregard, Brazlandia Rosada, and Brazlandia Roxa stood out as superior cultivars, with average yield ranging from 26 to 47 tons per ha. Overall, most cultivars exhibited a fusiform to near fusiform root shape, a good characteristic for the market, and were moderately affected by insects (attack incidence 1 to 30%). As global demand for energy continues to rise, selecting new cultivars of sweet potatoes with increased resistance to nematode diseases and with high yield will be important for food security and biofuel production.