Molecular Characterization and Susceptibility Assessment of Banana Genotypes to Root-Knot Nematode Resistance

Abstract

This study evaluated the susceptibility of five banana cultivars—Zeif, Zeif Imported, Hindi, Grand Nain, and Maghrabi—to the root-knot nematode Meloidogyne incognita and identified molecular markers associated with resistance using ISSR analysis. All cultivars showed varying levels of susceptibility. “Zeif Imported” showed the highest nematode reproduction (1.82 times), while “Maghrabi” showed moderate reproduction (0.952 times). “Grand Nain” had a relatively low final nematode population (1733). Growth parameters including shoot, root, and total plant weights were reduced in all infected cultivars. The greatest reduction in shoot weight occurred in “Zeif Imported” (62.2%), whereas “Hindi” showed the lowest reduction (8.6%), indicating variable host reactions. DNA from healthy and infected plants was analyzed using nine ISSR primers to detect genetic polymorphisms. The primers generated 45 bands, 36 of which were polymorphic, with an average polymorphism of 80% and a PIC value of 0.70, indicating substantial genetic variability. Amplified fragments ranged from 200 to 1500 bp, and several unique bands appeared only in infected samples, suggesting genomic modifications caused by nematode stress. Cluster analysis grouped the cultivars into two distinct clusters, clearly separating resistant and susceptible genotypes. Primers UBC817, UBC815, and UBC850 produced 100% polymorphism, showing strong efficiency in detecting genetic differences. Overall, ISSR markers proved highly effective for identifying nematode-induced polymorphisms and distinguishing resistance levels among banana cultivars. This molecular approach enhances understanding of genetic diversity and resistance mechanisms in Musa spp. and supports breeding programs aimed at developing nematode-resistant banana varieties.