Webber John Bryan, Wada Sugae, Stockwell Virginia O, Wiman Nik G
Department of Horticulture, Oregon State University, Corvallis, OR, United States.
Horticultural Crops Research Unit, United States Department of Agriculture, Agricultural Research Service, Corvallis, OR, United States.
Front Plant Sci. 2021 Dec 17;12:800339. doi: 10.3389/fpls.2021.800339. eCollection 2021.
Bacterial blight of hazelnut ( L.) is caused by pv. (Xac). In the past, bacterial blight has been a key disease impacting the Oregon hazelnut industry where 99% of the United States hazelnut crop is grown. The disease is re-emerging in young orchards, as acreage of newly released hazelnut cultivars rapidly increases. This increase in hazelnut acreage is accompanied by renewed interest in developing control strategies for bacterial blight. Information on susceptibility of hazelnut cultivars to Xac is limited, partially due to lack of verified methods to quantify hazelnut cultivar response to artificial inoculation. In this research, Xac inoculation protocols were adapted to two hazelnut growing environments to evaluate cultivar susceptibility: tissue culture under sterile and controlled conditions, and potted tree conditions. Five hazelnut cultivars were evaluated using the inoculation protocol and seven hazelnut cultivars were evaluated using the inoculation protocol. Under conditions, there were severe bacterial blight symptoms on each cultivar consistent with those seen in the field, but no significant differences in the susceptibility of the newly released cultivars were observed compared to known Xac-susceptible cultivar ("Barcelona"). Under conditions, the proportion of necrotic buds were significantly higher in "Jefferson" and "Dorris" compared to all of the other tested cultivars, including "Barcelona." The symptom progression seen mirrored the timing and symptom progression of bacterial blight reported from field observations. The conditions significantly reduced the amount of time required to measure the inoculation efficiency compared to the environment and allowed for greater replication. Further studies on the effects of Xac can use the results of these experiments to establish a dose-response model for bacterial blight, a wider range of germplasm can be tested under conditions, and management strategies that can be evaluated on large populations of new cultivars using the methods.
榛子细菌性叶枯病（由杏黄单胞菌丁香假单胞菌致病变种（Xac）引起）。过去，细菌性叶枯病一直是影响俄勒冈州榛子产业的关键病害，美国99%的榛子作物都种植在该州。随着新推出的榛子品种种植面积迅速增加，这种病害在幼龄果园中再度出现。榛子种植面积的增加伴随着人们对制定细菌性叶枯病防治策略的新兴趣。关于榛子品种对Xac的易感性信息有限，部分原因是缺乏经过验证的方法来量化榛子品种对人工接种的反应。在本研究中，Xac接种方案适用于两种榛子种植环境以评估品种易感性：无菌和受控条件下的组织培养，以及盆栽树条件。使用一种接种方案评估了5个榛子品种，使用另一种接种方案评估了7个榛子品种。在一种条件下，每个品种都出现了与田间所见一致的严重细菌性叶枯病症状，但与已知的Xac易感品种（“巴塞罗那”）相比，新推出品种的易感性没有显著差异。在另一种条件下，“杰斐逊”和“多里斯”的坏死芽比例显著高于所有其他测试品种，包括“巴塞罗那”。在另一种条件下观察到的症状进展反映了田间观察报告的细菌性叶枯病的发病时间和症状进展。与另一种环境相比，该条件显著减少了测量接种效率所需的时间，并允许进行更多重复实验。关于Xac影响的进一步研究可以利用这些实验结果建立细菌性叶枯病的剂量反应模型，可以在该条件下测试更广泛的种质资源，并且可以使用该方法在大量新品种上评估管理策略。
