The reaction of thirteen peach and nectarine cultivars to Verticillium wilt

Verticillium wilt, caused by Verticillium dahliae, is one of the most important soil-borne diseases of stone-fruit trees.

Samples showing evidence of Verticillium wilt were collected from stone fruit orchards in the suburbs of Shahroud and Damavand and four isolates of V. dahliae were obtained. The fungal inoculum was prepared on sterile wheat grains and the response of 13 peach and nectarine cultivars propagated by grafting on GF305 (almond-peach hybrid) rootstock was inoculated with it in the canopy area in the garden in early spring. Sixteen weeks after inoculation, disease severity was recorded on a three-point scale.

All peach and nectarine cultivars were classified as very susceptible, susceptible, or semi-susceptible and none of them showed resistance. The Nectarine Independence cultivar was highly susceptible to disease, while the peach cultivar had the lowest disease severity index and was therefore classified as semi-susceptible.

Among these cultivars, the Romestar peach cultivar is less susceptible to the disease.