New pepper accessions proved to be suitable as a genetic resource for use in breeding nematode-resistant rootstocks

Root-knot nematodes (RKNs),Meloidogynespp., are considered, worldwide, as one of the main pathogens of solanaceous crops, including pepper (Capsicumspp.). Restrictions on the use of standard nematicides have motivated the development and use of resistant cultivars and rootstocks. Three genes in pepper, calledMe1,Me3andN, confer resistance to the three main RKN species (Meloidogyne incognita,Meloidogyne javanicaandMeloidogyne arenaria). However, their effectiveness seems to be limited because nematode populations that have overcome the resistance have been found, leading to a search for new sources of resistance and strategies to preserve their effectiveness. In two greenhouses and over a 7-month growing period, we evaluated the resistance toM. incognitaand the agronomic behaviour as rootstocks of nine pepper (Capsicum annuum) accessions – HDA330 (Me1carrier), Serrano Criollo de Morelos, (Me3carrier), Yolo Wonder (partially resistant) and another six accessions of unknown resistance originating from cultivars well adapted to the local growing conditions. The resistance conferred by theMe1gene was more robust than that conferred byMe3. Resistance toM. incognitawas found in four new accessions: P13, CTL, CT5, and P14. In P13, the level of resistance was similar to that of HDA330. The resistant accessions showed better agronomic behaviour than the susceptible accessions, which was most noticeable towards the final of the growing period. Some accessions constitute a potential resource for use in the genetic breeding of RKN-resistant rootstocks.