Kjær Erik Dahl, McKinney Lea Vig, Nielsen Lene Rostgaard, Hansen Lars Nørgaard, Hansen Jon Kehlet
Forest & Landscape, Faculty of Life Sciences, University of Copenhagen Frederiksberg, Denmark.
Evol Appl. 2012 Apr;5(3):219-28. doi: 10.1111/j.1752-4571.2011.00222.x. Epub 2011 Dec 3.
An emerging infectious pathogen Hymenoscyphus pseudoalbidus has spread across much of Europe within recent years causing devastating damage on European common ash trees (Fraxinus excelsior) and associated plant communities. The present study demonstrates the presence of additive genetic variation in susceptibility of natural F. excelsior populations to the new invasive disease. We observe high levels of additive variation in the degree of susceptibility with relatively low influence of environmental factors (narrow-sense heritability = 0.37-0.52). Most native trees are found to be highly susceptible, and we estimate that only around 1% has the potential of producing offspring with expected crown damage of <10% under the present disease pressure. The results suggest that the presence of additive genetic diversity in natural F. excelsior populations can confer the species with important ability to recover, but that low resistance within natural European populations is to be expected because of a low frequency of the hypo-sensitive trees. Large effective population sizes will be required to avoid genetic bottlenecks. The role of artificial selection and breeding for protection of the species is discussed based on the findings.
一种新出现的传染性病原体——拟白 Hymenoscyphus pseudoalbidus，近年来已在欧洲大部分地区传播，对欧洲白蜡树（欧洲白蜡）和相关植物群落造成了毁灭性破坏。本研究表明，天然欧洲白蜡种群对这种新的入侵疾病的易感性存在加性遗传变异。我们观察到易感性程度存在高水平的加性变异，环境因素的影响相对较小（狭义遗传力 = 0.37 - 0.52）。大多数本地树木被发现高度易感，并且我们估计在当前疾病压力下，只有约1% 的树木有可能产生预期树冠损伤小于10% 的后代。结果表明，天然欧洲白蜡种群中加性遗传多样性的存在可以赋予该物种重要的恢复能力，但由于低敏感树木的频率较低，预计欧洲天然种群的抗性较低。需要较大的有效种群规模以避免遗传瓶颈。基于这些发现，讨论了人工选择和育种对该物种保护的作用。
