Olive mycorrhization: Influences of genotype, mycorrhiza, and growing periods

The influence of mycorrhizal inoculation using two arbuscular mycorrhizal fungal species including Glomus mosseae and G. intraradices on some growth traits and phytochemicals of olive plantlets cultivars Koroneiki and Valanolia during 20-80 weeks after inoculation was studied. The results revealed that Valanolia had higher leaf area than Koroneiki, while Koroneiki had higher height, more number of lateral shoots and leaves, higher content of phenol and higher root colonization. There was no significant difference in leaf content of total chlorophylls and carotenoids between the cultivars. The fungal species did not show any significant difference in the traits studied, except for the percentage of root colonization, which was higher in the plantlets inoculated with G. intraradices. However, both the arbuscular mycorrhizal treatments significantly increased the plantlets height, stem diameter, number of lateral shoots and leaves, internode length, and leaf total phenols, chlorophylls and carotenoids. In contrast, they had no significant influences on leaf area. Among the attributes measured in this experiment, internode length, leaf area, total phenols and carotenoids did not change during the growing periods, while the other traits showed an increase from 20 to 80 weeks after inoculation. The positive effects of mycorrhiza inoculation observed in the present study may be beneficial and applicable to the commercial olive nurseries.