Identification of chili pepper genotypes (Capsicum spp.) resistant to meloidogyne enterolobii

Abstract

Chili pepper has economic importance and is the dominant Solanaceae in the market of spicy spices. Among the pathogens that affect this crop, Meloidogyne enterolobii is one of the most important because it presents a wide range of hosts and there are no resistance genes identified that are efficient against this species. The present study aimed to evaluate the reaction of chili pepper genotypes (Capsicum spp.) to M. enterolobii in order to identifify genetic resistance. Three experiments were conducted in a completely randomized design under greenhouse conditions: Experiment I, with 53 genotypes with ten replications; Experiment II, with twenty genotypes with ten replications; Experiment III in a 16 × 4 factorial scheme, with sixteen Capsicum spp. genotypes and four inoculum concentrations of M. enterolobii and eight replications. Inoculation was performed seven days after transplanting the Capsicum spp. seedlings into 2L plastic bags filled with sterilized soil and sand (2:1), using 4,000 eggs + J2/plant. Ninety days after inoculation (DAI) (Experiments I and II) and 60 DAI (Experiment III) nematode population density, reproduction factor (RF), fresh root mass, egg mass index (EMI) and gall index (GI) were evaluated. Genotypes with RF < 1.0 were considered resistant according to Oostenbrink (1966). Thirty one genotypes of Capsicum spp. showed resistance to M. enterolobii with RF ranging from 0.87 to 0.08. Seventeen resistant genotypes of C. chinensis presented RF lower than 0.85, ten genotypes of C. annuum had the RF lower than 0.75, three genotypes of C. frutescens had the RF lower than 0.87 and only one genotype of C. baccatum was resistant to M. enterolobii, presenting RF = 0.6. EMI and GI weren’t considered reliable variables to determine resistance and susceptibility. Fourteen genotypes rated as resistant in Experiments I and II were submitted to increasing concentrations of inoculum and, nevertheless, remained resistant.