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Highly infested soils undermine the use of resistant olive rootstocks as a control method of verticillium wilt
Author(s) -
Valverde Pedro,
Trapero Carlos,
Arquero Octavio,
Serrano Nicolás,
Barranco Diego,
Muñoz Díez Concepción,
LópezEscudero Francisco J.
Publication year - 2021
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/ppa.13264
Subject(s) - rootstock , verticillium wilt , verticillium dahliae , cultivar , biology , horticulture , verticillium , agronomy
Verticillium wilt of olive (VWO) is probably the most devastating fungal disease for olive trees worldwide, and currently the main cultivars are susceptible or moderately susceptible to this disease. The evaluation of resistant cultivars as rootstocks to control the disease has scarcely been explored, and mainly in short‐term studies under controlled conditions, which usually do not correspond with field evaluations. The main objective of this study was to assess the responses to VWO of different scion × rootstock combinations of the olive cultivars Picual, Arbequina, Changlot Real, and Frantoio in a long‐term field experiment with a soil highly infested with the defoliating pathotype of Verticillium dahliae . The results showed that grafting the susceptible cultivar Picual onto resistant rootstocks delayed the onset of the disease symptoms; however, after 4 years, it was observed that all combinations that contain Picual (a) were extensively colonized by V . dahliae ; (b) developed severe symptoms of the disease; and (c) had plant mortality similar to Picual growing on its own roots. This result highlights the importance of long‐term field experiments to evaluate VWO and shows that grafting susceptible olive cultivars onto resistant ones does not provide a durable control of VWO under high inoculum potential, as V . dahliae is able to progress through the resistant rootstock and then extensively colonize and kill the susceptible scion. However, the high inoculum potential observed in this study does not allow us to consider the evaluated resistant cultivars as completely ineffective under lower inoculum densities.