Guo Yonghong, Olsen Richard T, Kramer Matthew, Pooler Margaret
U.S. Department of Agriculture/Agricultural Research Service, U.S. National Arboretum - Floral and Nursery Plants Research Unit, Beltsville, MD 20705.
U.S. Department of Agriculture/Agricultural Research Service, Statistics Group, Beltsville, MD 20705.
Plant Dis. 2016 Aug;100(8):1622-1626. doi: 10.1094/PDIS-01-16-0016-RE. Epub 2016 May 3.
Boxwood blight caused by Calonectria pseudonaviculata is a newly emergent disease of boxwood (Buxus spp. L.) in the United States that causes leaf drop, stem lesions, and plant death. A rapid and reliable laboratory assay that enables screening hundreds of boxwood genotypes for resistance to boxwood blight is needed to enable breeding and selection of resistant cultivars. Using eight boxwood cultivars with differing susceptibilities, we examined parameters for a screening assay comparing whole plant inoculation with detached leaf inoculation, use of mycelium versus spores as the inoculum, comparison of times of the year for inoculation, and comparison of two leaf inoculation methods. Inoculation of detached leaves gave comparable results to inoculation of whole plants when compared across genotypes, although the detached leaf assay resulted in greater percentages of symptom expression. The time of year of plant inoculation (spring, summer, or winter) did not affect the relative expression of symptoms among the most resistant and susceptible genotypes. Inoculating plants with mycelium was as effective as spore inoculation for causing disease symptoms and allowed us to distinguish the more resistant genotypes, yet mycelium inoculation was much easier to prepare in large quantities for multiple assays.
由拟舟形弯孢菌引起的黄杨枯萎病是美国黄杨（黄杨属植物）新出现的一种病害，可导致叶片脱落、茎部病斑和植株死亡。需要一种快速可靠的实验室检测方法，以便能够筛选数百种黄杨基因型对黄杨枯萎病的抗性，从而进行抗病品种的培育和选择。我们使用八个敏感性不同的黄杨品种，研究了一种筛选检测方法的参数，该方法比较了整株接种与离体叶片接种、使用菌丝体与孢子作为接种物、一年中不同接种时间以及两种叶片接种方法的比较。跨基因型比较时，离体叶片接种与整株接种的结果相当，尽管离体叶片检测导致症状表达的百分比更高。植株接种的时间（春季、夏季或冬季）并不影响最抗病和最感病基因型之间症状的相对表达。用菌丝体接种植株引发病害症状的效果与孢子接种一样，并且使我们能够区分抗性更强的基因型，然而菌丝体接种更容易大量制备用于多次检测。
