Plant parasitic nematodes communities associated with olive trees in Morocco
Résumé
Plant-parasitic nematodes significantly contribute to economic losses in the ten top olive
producing countries in the world, especially in the Mediterranean basin (Spain, Italy, Greece,
Tunisia, and Morocco).Diversity and structures of plant-parasitic nematode communities respond
to evolutionary, environmental and anthropogenic forces. Instead of controlling the main pathogenic
nematode species as usual, one of the innovative strategies to control plant-parasitic nematodes would
be to manage diversity in communities in order to lead them to be less pathogenic. The present study
aims at understanding the contribution of olive domestication and human impacts on the plantparasitic
nematode communities by analyzing the diversity of plant-parasitic nematodes in cultivated
olive compared to wild olive in Morocco. Thus, 220 samples were collected in 2012 in several sites with
cultivated and feral olive trees (i.e. wild olive resulting from cultivated olive) in the olive production areas
located all along the Atlas foothills, as well as on wild olive Morphobiometric observations revealed
a significant diversity of plant-parasitic nematodes, belonging to 12 families and 28 genera. Our results
showed the presence of genera Pratylenchus and Meloidogyne in all sampled systems that are known
harmful taxa for agriculture especially in nurseries. These two genera were more abundant in the
cropped systems. Principal component analysis revealed no significant effect of olive systems on
the diversity of PPN in communities but on the PPN community patterns Other factors such as
olive genotype, soil physic-chemical characteristics, geo-climatic characteristics, associated plants with
olive trees will also be discussed as major factors affecting the plant-parasitic nematode community
patterns.