McKeever Kathleen M, Johnson Jeremy S, Chastagner Gary A
USDA Forest Service, Forest Health Protection Asheville Field Office, Asheville, NC 28801, U.S.A.
Department of Forestry, Michigan State University, East Lansing, MI 48824, U.S.A.
Plant Dis. 2025 Jul;109(7):1563-1571. doi: 10.1094/PDIS-08-24-1679-RE. Epub 2025 Jul 23.
Turkish fir () has been evaluated as a Phytophthora root rot (PRR)-resistant alternative to other PRR-susceptible Christmas tree species. Although Turkish fir survival under heavy PRR disease pressure exceeds that of other host species, previous research has suggested that there may be variability in resistance owing to pedigree, ambient environment, and species. To assess differences in PRR survival in the field, 36 open-pollinated families of Turkish fir were challenged with a mixture of five species of under conditions conducive for disease. Seedlings were grown from seed that was gathered during a provenance collection effort from three provinces in Turkey. At the collection locations in each province, mother trees were located along an altitudinal gradient. The goals for this study included determining Turkish fir resistance in comparison with susceptible fir species, evaluating phenotype among Turkish fir families, assessing whether differences in phenotypes could be attributable to source location or elevation, determining whether source province or elevation influenced mortality, and comparing recovery of the five species used as inoculum. Turkish fir was demonstrated to be more resistant than noble fir () or Fraser fir () under the experimental conditions. Among the 36 Turkish fir families, 6 had a significantly lower probability of PRR mortality compared with all other families; half of these families were from the Karabük province. Similarly, Karabük province had the lowest overall mortality when family mortality proportions were totaled and compared among provinces. Evaluation of mortality among families from higher elevation sites within a province showed reduced mortality in comparison with middle and lower elevation sites, with variation among seed sources from different provinces. Among the five species of bulked for inoculum, was the predominant species recovered from dead seedlings in both years. Results suggest that Turkish fir may be a viable PRR-resistant option for utilization in the Christmas tree industry despite some variability in phenotype among family.
土耳其冷杉（）已被评估为一种对疫霉根腐病（PRR）具有抗性的树种，可作为其他易感染PRR的圣诞树品种的替代品。尽管在严重的PRR病害压力下，土耳其冷杉的存活率超过了其他寄主物种，但先前的研究表明，由于谱系、环境和物种的不同，其抗性可能存在差异。为了评估田间PRR存活率的差异，在有利于疾病发生的条件下，用五种疫霉的混合物对36个土耳其冷杉自由授粉家系进行了挑战。幼苗由从土耳其三个省份进行种源收集时采集的种子培育而成。在每个省份的采集地点，母树沿着海拔梯度分布。本研究的目标包括：与易感冷杉品种相比，确定土耳其冷杉的抗性；评估土耳其冷杉家系之间的表型；评估表型差异是否可归因于来源地或海拔；确定来源省份或海拔是否影响死亡率；比较用作接种物的五种疫霉的回收率。在实验条件下，土耳其冷杉被证明比壮丽冷杉（）或弗雷泽冷杉（）更具抗性。在36个土耳其冷杉家系中，有6个家系的PRR死亡率显著低于所有其他家系；其中一半的家系来自卡拉比克省。同样，当将家系死亡率比例汇总并在各省之间进行比较时，卡拉比克省的总体死亡率最低。对一个省内较高海拔地点的家系死亡率进行评估，结果表明与中低海拔地点相比死亡率降低，不同省份的种子来源存在差异。在用于接种的五种疫霉中，两年中从死亡幼苗中回收的主要疫霉是。结果表明，尽管家系之间的表型存在一些差异，但土耳其冷杉可能是圣诞树产业中一种可行的抗PRR选择。
