Evaluation of the wildActinidiagermplasm for resistance toPseudomonas syringaepv.actinidiae

Abstract Bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa) is a catastrophic disease that threatens the global kiwifruit industry. As yet, no cure has been developed. Planting resistant cultivars is considered as one of the most effective ways to control Psa. However, most existing cultivars lack Psa‐resistance genes. Wild Actinidia resources contain rich genetic diversity and may have powerful disease‐resistance genes under long‐term natural selection, but lack of knowledge about the resistance to Psa for most Actinidia species results in some excellent wild resistant genotypes being underutilized. In this study, the response to Psa of 104 wild genotypes of 30 Actinidia species (including 37 taxa) was tested with an in vitro bioassay, and a considerable number of individuals from different species with tolerance or high resistance to Psa were identified. The results showed high consistency between years. This is the first large‐scale evaluation of diverse Actinidia species with resistance to Psa through an in vitro bioassay. The resistant genotypes of A. chinensis identified could be used in future kiwifruit improvement programmes. The findings should help provide an understanding of the resistance to Psa.