Data from: Fitness dynamics within a poplar hybrid zone: II. Impact of exotic sex on native poplars in an urban jungle.

Trees bearing novel or exotic gene components are poised to contribute to the bioeconomy for a variety of purposes such as bioenergy production, phytoremediation, and carbon sequestration within the forestry sector, but sustainable release of trees with novel traits in large-scale plantations requires the quantification of risks posed to native tree populations. Over the last century, exotic hybrid poplars produced through artificial crosses were planted throughout eastern Canada as ornamentals or windbreaks and these exotics provide a proxy by which to examine the fitness of exotic poplar traits within the natural environment to assess risk of exotic gene escape, establishment, and spread into native gene pools. We assessed postzygotic fitness traits of native and exotic poplars within a naturally regenerated stand in eastern Canada (Quebec City, QC). Pure natives (P. balsamifera and P. deltoides spp. deltoides), native hybrids (P. deltoides × P. balsamifera), and exotic hybrids (trees bearing Populus nigra and P. maximowiczii genetic components) were screened for reproductive biomass, yield, seed germination, and fungal disease susceptibility. Exotic hybrids expressed fitness traits intermediate to pure species and were not significantly different from native hybrids. They formed fully viable seed and backcrossed predominantly with P. balsamifera. These data show that exotic hybrids were not unfit and were capable of establishing and competing within the native stand. Future research will seek to examine the impact of exotic gene regions on associated biotic communities to fully quantify the risk exotic poplars pose to native poplar forests.

携带新型或外来基因组分的林木，可为生物经济贡献力量，其应用场景涵盖林业领域的生物能源生产、植物修复与碳汇等多种用途；但在大规模人工林可持续释放具备新颖性状的林木时，需量化其对本土林木种群构成的风险。过去一个世纪以来，通过人工杂交培育的外来杂交杨被广泛种植于加拿大东部，用作观赏植物或防风林；这些外来树种可作为替代研究模型，用以探究外来杨性状在自然环境中的适合度，进而评估外来基因逃逸、定植并扩散至本土基因库的风险。本研究针对加拿大东部（魁北克省魁北克市）一处自然更新林分中的本土与外来杨树开展了合子后适合度性状评估。研究对象包括纯种本土杨树（P. balsamifera和P. deltoides spp. deltoides）、本土杂交杨（P. deltoides × P. balsamifera）以及携带黑杨（Populus nigra）和P. maximowiczii遗传组分的外来杂交杨，对其繁殖生物量、产量、种子萌发率及真菌病害易感性进行了筛选。结果显示，外来杂交杨的适合度性状介于纯种物种之间，且与本土杂交杨无显著差异；它们可产生完全具有活力的种子，并主要与P. balsamifera回交。本研究数据表明，外来杂交杨并非缺乏适合度，而是能够在本土林分中定植并竞争生存。后续研究将聚焦于外来基因区域对相关生物群落的影响，以全面量化外来杨树对本土杨树林构成的风险。