Reforestation in the British Isles (UK and Ireland) has been dominated with the use of an exotic conifer tree species, Sitka spruce (Picea sitchensis [Bong.] Carr.). Sitka breeding in the UK was developed from a single provenance, the Haida Gwaii Islands (Canada), which is both well suited to the British climate and highly susceptible to the white pine weevil (Pissodes strobi L.) in its native range. We examined variation and heritability of insect resistance related traits and assessed potential trade-offs with tree growth in 50 full-sibling families and 13 clonally replicated genotypes growing in the UK. We measured bark levels of three terpenes (dehydroabietic acid, (+)-3-carene and terpinolene) shown to confer resistance to the white pine weevil in Sitka spruce’s native range, on the principle that these defence compounds may also contribute to pest resistance in the UK. We compared our results with published findings from the native range and also used individuals from a Haida Gwaii seed lot grown in the UK for comparison of terpene levels. Dehydroabietic acid content in the UK breeding population was similar to populations from resistant native populations, but (+)-3-carene and terpinolene levels were relatively low. Narrow sense heritability for dehydroabietic acid, (+)-3-carene and terpinolene was estimated as 0.20, 0.93 and 0.98, respectively from the full-sib data, and this evidence of genetic variance was supported by estimates of broad sense heritability from the smaller clonal study. Terpene content was found to be positively correlated to growth traits. The heritability estimates and genetic correlations indicate that selective breeding should be effective in raising levels in the UK breeding population of the three candidate terpenes implicated in weevil resistance. However, low levels observed indicate that other provenances from the native range may produce greater short-term improvements for two of the terpenes.

中文翻译：

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陌生土地上的陌生人：英国 Sitka 云杉 (Picea sitchensis [Bong.] Carr.) 原生昆虫抗性生物标志物的遗传变异

不列颠群岛（英国和爱尔兰）的重新造林以使用外来针叶树种 Sitka spruce（Picea sitchensis [Bong.] Carr.）为主。英国的 Sitka 育种是从一个单一的起源地发展而来的，即海达瓜伊群岛（加拿大），它既非常适合英国的气候，又非常容易受到原生地白松象鼻虫 (Pissodes strobi L.) 的影响。我们检查了昆虫抗性相关性状的变异和遗传力，并评估了在英国生长的 50 个全兄弟家庭和 13 个克隆复制基因型与树木生长的潜在权衡。我们测量了三种萜烯（脱氢枞酸、(+)-3-蒈烯和萜品油烯）的树皮含量，这些萜烯对 Sitka 云杉原生地的白松象鼻虫具有抗性，原则是这些防御化合物也可能有助于英国的害虫抗性。我们将我们的结果与来自本地范围的已发表研究结果进行了比较，并且还使用了来自英国种植的 Haida Gwaii 种子批次的个体来比较萜烯水平。英国繁殖种群中的脱氢枞酸含量与来自抗性本地种群的种群相似，但 (+)-3-蒈烯和萜品油烯水平相对较低。从全同胞数据估计，脱氢枞酸、(+)-3-蒈烯和萜品油烯的狭义遗传力分别为 0.20、0.93 和 0.98，遗传变异的这一证据得到了来自较小的广义遗传力的估计的支持。克隆研究。发现萜烯含量与生长性状呈正相关。遗传力估计和遗传相关性表明，选择性育种应有效提高英国育种种群中与象鼻虫抗性有关的三种候选萜烯的水平。然而，观察到的低水平表明，来自本地范围的其他来源可能会对两种萜烯产生更大的短期改进。