Identification of sources of resistance to Meloidogyne spp. in striped jalapeño pepper (Capsicum annuum L.)

Abstract

Objective: To identify striped jalapeño chili pepper (Capsicum annuum L.) plants as a source of genotypes resistant to Meloidogyne enterolobii and Meloidogyne incognita, enabling genetic diversification in the development of improved cultivars within breeding programs.

Design/methodology/approach: The resistance of 15 striped jalapeño chili pepper accessions native to northern Hidalgo State was evaluated against M. enterolobii (Me) and 12 accessions against M. incognita (Mi). The experimental unit consisted of one plant per replicate, with four replicates per accession. Each plant was inoculated with 1000 J2, obtained monoxenically from Me and Mi. The susceptible control was the California Wonder (CW) cultivar for both Meloidogyne species, while the resistant control against Mi was line CM-334. Resistance was assessed using the following variables: number of galls, number of egg masses, number of eggs per gram of root, and reproduction index. Evaluations were performed 34 days after inoculation (dai) for Me and 42 dai for Mi. A randomized complete block design was employed, and statistical analysis was performed using R Studio.

Results: Accessions CP922, CP933, CP937, CP938, CP939, and CP946 exhibited resistance to both nematode species. In addition, accessions CP932, CP903, and CP942 showed specific resistance to Mi, whereas CP941 and CP935 displayed resistance to Me. In particular, striped jalapeño accessions CP922, CP933, CP937, CP938, CP939, and CP946 demonstrated a response ranging from moderately resistant to highly resistant against both Meloidogyne species.

Limitations on study/implications: This work represents a fundamental starting point, as it constitutes the first effort aimed at identifying plant species resistant to root-knot nematodes on jalapeño chili pepper. However, the findings correspond to an initial exploratory phase, and the characterization carried out does not yet clarify the physiological, biochemical, or molecular mechanisms underlying the observed resistance. This limits its immediate application in genetic improvement or integrated pest management programs. Therefore, further research incorporating molecular biology, transcriptomics, and metabolomics tools is required to validate the potential of these species as strategic genetic resources.

Findings/conclusions: The identified accessions represent a promising alternative for use and further study in Capsicum spp. breeding programs against the root-knot nematodes Meloidogyne enterolobii and Meloidogyne incognita.