Striving Towards an Operational Disease Resistance Program for ‘Ōhiʻa Against the Fungal Pathogen Ceratocystis lukuohia

The ʻŌhiʻa Disease Resistance Program (ʻŌDRP), a collaboration between the US Forest Service - Institute of Pacific Islands Forestry, and the Akaka Foundation for Tropical Forests, aims to identify and propagate ʻōhiʻa (Metrosideros polymorpha) resistant to the rapid ʻōhiʻa death (ROD) pathogen, Ceratocystis lukuohia. To date ʻŌDRP has conducted five screening trials of ʻōhiʻa and discovered genotypes exhibiting little to no external foliar wilt symptoms, indicating potential resistance. These surviving ʻōhiʻa will be planted on high ROD hazard sites to assess long-term survival and potential breeding efforts. Our findings suggest that the majority of ʻōhiʻa are susceptible to C. lukuohia infection. However, the wildtype resistance discovered in these trials offers hope for restoration with ROD-resistant ʻōhiʻa. We hope to grow our program to an operational level that can serve a variety of stakeholders wanting to replant and restore forests with our disease-resistant material.