Water Consumption and Vegetative Growth Progress in Resistant and Susceptible Olive Cultivars Infected by Verticillium dahliae
Purpose: Water consumption and vegetative growth in resistant (“Frantoio”) and susceptible (“Picual”) olive cultivars infected with Verticillium dahliae were assessed. Methods: Plants were inoculated with the pathogen and disease evaluated in growth chamber. Mean daily water consumption and vegetative growth were recorded during 13 weeks. Results: Water consumption significantly decreased in inoculated plants compared to non-inoculated plants during the 3rd - 6th weeks after inoculation period. From the 9th week, a significantly lower consumption occurred in infected “Picual” plants compared with “Frantoio” plants. Vegetative growth was reduced in inoculated plants of both cultivars, although the reduction of the fresh weight was remarkably higher in “Picual” compared with controls due to defoliation and tissue desiccation, impeding the production of new shoots and leaves. Conversely, in “Frantoio”, defoliation was significantly reduced to low levels. Conclusions: Water consumption and vegetative growth in plants of resistant (“Frantoio”) and susceptible (“Picual”) olive cultivars inoculated by Verticillium dahliae were consistently associated with the progress of the wilt symptoms and the level of resistance of the cultivar. Growth and water consumption reductions in “Picual” were irreversible in almost all plants, while “Frantoio” plants were able to maintain water translocation, overcome the infection and avoid vascular occlusion, and restart vegetative growth.