RESISTANCE OF ARRACACHA GENOTYPES TO MELOIDOGYNE JAVANICA AND MELOIDOGYNE INCOGNITA UNDER FIELD CONDITIONS
The losses caused by Meloidogyne spp. (root-knot nematodes) are one of the main problems for the production of arracacha (Arracacia xanthorrhiza) in Brazil. Meloidogyne spp. are widely disseminated in arracacha production areas. An integrated nematode management approach is required, and an important component of this approach is genetic resistance. Studies on the reaction of arracacha genotypes to Meloidogyne spp. are scarce. Therefore, the objective of this study was to evaluate arracacha genotypes for resistance to Meloidogyne spp. The genotypes selected for evaluation have the potential to be used by farmers, when available, or by breeding programs. Forty genotypes of arracacha, 39 with yellow-colored flesh, and one with white-colored flesh were evaluated. Arracacha ‘Amarela Comum’ and a white-fleshed variety ‘Branca’ were included as susceptible and resistant controls, respectively. The experiments were conducted in a field naturally infested with a mixed population of Meloidogyne javanica and Meloidogyne incognita race 1 in 2011/2012 and 2013/2014. At harvest, root galling was rated and total and commercial storage root mass (t/ha) measured. The mixed population of M. incognita race 1 and M. javanica significantly affected the quality of arracacha roots and yield. Of the genotypes currently available to growers, ‘Amarela de Senador Amaral’ and ‘Branca’ were more resistant to Meloidogyne spp. compared to ‘Amarela Comum’, ‘BRS Rúbia 41’, ‘BRS Acarijó 56’, and ‘BRS Catarina 64’. Genotypes CNPH-25, CNPH-26, and CNPH-46 were superior for Meloidogyne spp. resistance and storage roots mass, making them the most suitable candidates to become new cultivars, or for use in crosses aiming to develop new cultivars that have high-yield potential, yellow-colored flesh, and resistance to Meloidogyne spp.