Use of resistant cardoons as rootstocks for the control of verticillium wilt in globe artichoke

Grafting plants onto resistant rootstocks could represent a quick method that may enable the susceptible scion to control the soil borne disease. A program, aimed at verifying the possibility of using globe artichoke plants grafted on Verticillium resistant rootstocks, is in progress. Our work aims at (a) recovering sources of a resistance to V. dahliae in a collection of wild and cultivated cardoons, and (b) at evaluating the possibility to apply grafting technique to globe artichoke by utilizing disease resistant cardoon as rootstocks. In our work, a collection of wild and cultivated cardoons has been tested, under controlled conditions, for resistance to V. dahliae by artificial inoculations with a conidial suspension of the fungus. Out of 44 populations obtained by open pollination in the field, 9 of them showed a high level of resistance to Verticillium wilt without any symptoms. Initial results are showing that, for the success of grafting, it is necessary (i) to adjust the amount of light during seed germination and young seedling growth in order to favour the development of the hypocotyls and so physically allow grafting technique; (ii) to synchronize the time of sowing for the two bionts. On the basis of the experience gained so far, a positive view on the grafting practice can be expressed also for globe artichoke. Therefore, the use of plants grafted onto rootstocks resistant to the most dangerous soil borne pathogens can be considered as an useful agronomical technique, mainly in areas where the soil weakness is particularly important. © ISHS.