Data for An Assay To Rapidly Estimate Host Resistance To Walnut Twig Beetle Feeding

<p><span style="font-size:12pt"><span style="line-height:115%"><span style="font-family:Aptos,sans-serif"><span new="" roman="" style="font-family:" times=""><span style="color:black">Thousand cankers disease (TCD) is a devastating fungal disease of <i>Juglans</i> spp. and the causal agent is vectored by the walnut twig beetle (WTB). Control methods for the vector and pathogen have been explored, but the development of TCD-resistant black walnut cultivars offers the most promising long-term solution. A critical first step in this process is identifying and comparing relative resistance to WTB feeding in walnut accessions. This study describes an assay developed to rapidly screen for resistance to WTB feeding in black walnut genetic lines. We used a detached bolt assay to evaluate three metrics of beetle performance to infer resistance: beetle reproduction, phloem consumption, and adult beetle mass. We hypothesized that genetic variation in walnut would drive phenotypic differences that would result in a gradient of resistance to WTB across genotypes. We predicted that more resistant trees would have reduced beetle emergence, increased phloem consumption, and smaller adult beetles. We found significant differences in the numbers of emerging WTB across the 14 cultivars assayed, with ~10x more beetles emerging from the most susceptible genotype than the most resistant genotype. We found limited or no evidence of differences across genotypes for the other performance metrics measured. This assay can enable breeders to rapidly identify promising candidate trees for long-term field trials without jeopardizing standing populations of walnut, serving as a critical first step in resistance breeding, with potential applications in improvement of both black walnut and other tree species threatened by woodboring pests. </span></span></span></span></span></p>