Plant parasitic nematodes communities associated with olive trees in Morocco

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