Phytophthora Resistance

Developing Phytophthora-resistant fir Christmas trees

Fraser fir cultured as Christmas trees is one of North Carolina’s largest specialty crops with an annual revenue exceeding $100 million. The most severe disease in Fraser fir nurseries and plantations is Phytophthora root rot which afflicts the industry with an estimated $6 million in losses annually. Because Fraser fir has no innate resistance, the NCSU Christmas Tree Genetics Program has begun evaluation of two exotic species that show promise as quality Christmas tree species and also possess some Phytophthora resistance.
Genetic control of resistance to a single Phytophthora genotype has been confirmed. The research will assess resistance in these fir species to a broader array of Phytophthora genotypes and use next generation sequencing technology to develop DNA markers to select for resistance in genetic field trials.
The technology and knowledge generated will be applied toward developing Phytophthora-resistant fir planting stock targeted for sites with known disease problems and will ultimately abate the adverse impact of this disease on the state’s Christmas tree industry.

A survey of Phytophthora species in Fraser fir Christmas tree plantations in the southern Appalachians

Martin Pettersson is working in a survey of Phytophthora in Fraser fir Christmas tree plantations. Symptomatic Fraser fir roots have been collected in commercial production fields distributed over 14 counties in three states in the Southern Appalachians. Roots from individual trees were transferred to a selective media and small tufts of mycelium were taken from the pure cultures that morphologically resembled Phytophthora spp. After DNA extraction, at least six species of Phytophthora were identified. Martin is working in the analysis of data and the identification methods and soon we will include more results in our website!