Locally adapted temperate tree populations exhibit genetic trade-offs among climate-related traits that can be exacerbated by selective breeding and are challenging to manage under climate change. To inform climatically adaptive forest management, we investigated the genetic architecture and impacts of selective breeding on four climate-related traits in 105 natural and 20 selectively bred lodgepole pine populations from western Canada. Growth, cold injury, growth initiation, and growth cessation phenotypes were tested for associations with 18,600 single-nucleotide polymorphisms (SNPs) in natural populations to identify “positive effect alleles” (PEAs). The effects of artificial selection for faster growth on the frequency of PEAs associated with each trait were quantified in breeding populations from different climates. Substantial shifts in PEA proportions and frequencies were observed across many loci after two generations of selective breeding for height, and responses of phenology-associated PEAs differed strongly among climatic regions. Extensive genetic overlap was evident among traits. Alleles most strongly associated with greater height were often associated with greater cold injury and delayed phenology, although it is unclear whether potential trade-offs arose directly from pleiotropy or indirectly via genetic linkage. Modest variation in multilocus PEA frequencies among populations was associated with large phenotypic differences and strong climatic gradients, providing support for assisted gene flow polices. Relationships among genotypes, phenotypes, and climate in natural populations were maintained or strengthened by selective breeding. However, future adaptive phenotypes and assisted gene flow may be compromised if selective breeding further increases the PEA frequencies of SNPs involved in adaptive trade-offs among climate-related traits.

当地适应的温带树木种群在与气候相关的性状之间表现出遗传权衡，选择性育种可能会加剧这种情况，并且在气候变化下管理具有挑战性。为了为气候适应性森林管理提供信息，我们调查了加拿大西部 105 个天然和 20 个选择性繁殖的黑松种群的遗传结构和选择性育种对四种气候相关性状的影响。测试了生长、冷损伤、生长开始和生长停止表型与自然种群中 18,600 个单核苷酸多态性 (SNP) 的关联，以确定“积极效应等位基因”(PEA)。在来自不同气候的育种种群中量化了人工选择以加快生长对与每个性状相关的 PEA 频率的影响。经过两代的高度选择性育种后，在许多位点观察到 PEA 比例和频率的显着变化，并且与物候相关的 PEA 的响应在气候区域之间存在很大差异。性状之间存在广泛的遗传重叠。与更高的身高最密切相关的等位基因通常与更大的冷损伤和延迟物候相关，尽管尚不清楚潜在的权衡是直接来自多效性还是通过遗传连锁间接产生。种群间多位点 PEA 频率的适度变化与大的表型差异和强烈的气候梯度有关，为辅助基因流动策略提供了支持。自然种群中基因型、表型和气候之间的关系通过选择性育种得以维持或加强。然而，