Sweetpotato Genotypes ‘CIP BRS Nuti’ and ‘Canadense’ Are Resistant toMeloidogyne incognita,M.javanica, andM.enterolobii

Abstract

Sweet potato is a staple crop in Brazil presenting a smaller number of pathogens and diseases in comparison with other root and tuberous crops. Root knot nematodes are among the most serious sweet potato root pathogens. The impact of these pathogens also extends to following crops. Since in Brazil it is common to cultivate more than one crop per season this problem is rapidly disseminated. The aim of this study is to assess the resistance of two sweet potato clones and three commercial sweet potato genotypes to three different Meloidogyne species. Assays were performed under greenhouse conditions in two separate seasons. CIP BRS Nuti, one of the new clones and Canadense, one of the commercial genotypes were resistant to Meloidogyne incognita, M. javanica and M. enterolobii. This finding was obtained based on the reproduction factor smaller than 0,2 meaning that the initial population of 5,000 nematodes was reduced to less than 1,000 individuals after 90 days of inoculation. This data was also confirmed by the small number of eggs, egg masses and galls. Tomato and sweet potato cultivar Beauregard, known to be susceptible to the three nematode species were highly damaged by the pathogens. To our knowledge CIP BRS Nuti and Canadense are the first South American commercial cultivars with triple nematode resistance.