Assessment of new genetic resources to uncover potential nematode resistance traits for eggplant (Solanum melongena) improvement

Abstract

Eggplant (S. melongena L.) belongs to Solanaceae and is cultivated worldwide. Root-knot nematodes (RKN), Meloidogyne spp., are among the most important pathogens affecting eggplant production both in greenhouse and open field cultivation. Chemical control was carried out for many years, but their excessive usage is harmful for both human and environmental health. Genetic improvement of eggplant is the best environmentally friendly alternative method for the containment of pests, also providing sustainable production in growing areas. Thus, it is necessary to characterize the available germplasm of cultivated eggplant as well as of allied and wild species to uncover potential sources of resistance exploitable for breeding. To date, there is no sufficient information available on resistance sources to nematodes for eggplant. In this study, some new potential resistance sources to M. incognita race 1, the most common nematode species affecting eggplant worldwide, were investigated. Plantlets of 15 genotypes, including eggplant varieties, heirlooms, allied species, and interspecific hybrids, were inoculated with second stage juveniles (J2), and disease assessment was performed by visually evaluating galls on the roots using a 0-5 scale and by counting egg masses/galls on plant root system and J2 in soil. Among the genotypes tested, a strong resistance source was detected in both S. torvum and S. tomentosum, being this latter the best candidate exploitable for breeding programs as this species is crossable with eggplant and ILs are already available.