In a warming climate, the ability to accurately predict and track shifting environmental conditions will be fundamental for plant survival. Environmental cues define the transitions between growth and dormancy as plants synchronise development with favourable environmental conditions, however these cues are predicted to change under future climate projections which may have profound impacts on tree survival and growth. Here, we use a quantitative genetic approach to estimate the genetic basis of spring and autumn phenology in Populus trichocarpa to determine this species capacity for climate adaptation. We measured bud burst, leaf coloration, and leaf senescence traits across two years (2017–2018) and combine these observations with measures of lifetime growth to determine how genetic correlations between phenology and growth may facilitate or constrain adaptation. Timing of transitions differed between years, although we found strong cross year genetic correlations in all traits, suggesting that genotypes respond in consistent ways to seasonal cues. Spring and autumn phenology were correlated with lifetime growth, where genotypes that burst leaves early and shed them late had the highest lifetime growth. We also identified substantial heritable variation in the timing of all phenological transitions (h2 = 0.5–0.8) and in lifetime growth (h2 = 0.8). The combination of additive variation and favourable genetic correlations in phenology traits suggests that populations of cultivated varieties of P. Trichocarpa may have the capability to adapt their phenology to climatic changes without negative impacts on growth.

中文翻译：

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落叶树Populus trichocarpa（Torr. and Gray）适应性物候性状的定量遗传结构

在气候变暖的情况下，准确预测和跟踪不断变化的环境条件的能力将是植物生存的基础。环境线索定义了生长和休眠之间的过渡，因为植物使发育与有利的环境条件同步，但是这些线索预计会在未来的气候预测下发生变化，这可能对树木的生存和生长产生深远的影响。在这里，我们使用定量遗传方法来估计毛果杨春季和秋季物候学的遗传基础，以确定该物种的气候适应能力。我们测量了芽的破裂、叶子的着色，两年（2017-2018 年）的叶片衰老性状，并将这些观察结果与终生生长的测量相结合，以确定物候和生长之间的遗传相关性如何促进或限制适应。尽管我们发现所有性状都有很强的跨年遗传相关性，但不同年份之间的转变时间不同，这表明基因型以一致的方式对季节性线索做出反应。春季和秋季物候与终生生长相关，其中早破叶子和晚脱落的基因型具有最高的终生生长。我们还确定了所有物候转变时间（h2 = 0.5-0.8）和终生生长（h2 = 0.8）的显着遗传变异。