Screening of Young Olive Trees for Resistance to the Root‐Knot Nematode <i>Meloidogyne javanica</i>

Abstract

ABSTRACT The olive tree ( Olea europaea L.) is considered one of the most important fruit‐producing crops across the Mediterranean Basin. Despite its importance, this crop remains vulnerable to infection by root‐knot nematodes, Meloidogyne spp., and only a few cultivars with partial resistance to these nematodes have been identified. This study aimed to determine the response of olive cultivars to M. javanica infection. Six cultivars (Koroneiki, Arbequina, Arbosana, Picholine Marocaine, Menara and Haouzia) were infected with 1500 s‐stage juveniles (J2s) per 1 kg of soil. Morpho‐physiological metrics and M. javanica reproduction [final population, reproduction factor (RF)] were assessed after 9 months of incubation in the greenhouse. Morphological and physiological metrics were not affected by nematode infection, except for plant height, which was reduced for the Koroneiki cultivar. Regarding nematode reproduction, Koroneiki and Arbosana cultivars had significantly higher final populations (Pf &gt; 300 per 100 g soil) and reproductive factors (RF &gt; 2). In contrast, Menara and Arbequina recorded the lowest Pf (&lt; 40) and RF (&lt; 0.3). The Picholine Marocaine variety showed intermediate susceptibility, with reproductive parameters between those of the resistant and susceptible varieties. Overall, Menara, Arbequina and Haouzia were resistant to M. javanica , whereas Koroneiki and Arbosana were highly susceptible, with Picholine Marocaine showing an intermediate response.