Resources allocated to survival cannot be used to increase fecundity, but the extent to which this trade-off constrains adaptation depends on overall resource status. Adaptation to local environmental conditions may therefore entail the evolution of traits that increase the amount of resources available to individuals (their resource status or ‘condition’). We examined the relative contribution of trade-offs and increased condition to adaptive evolution in a recombinant inbred line population of Arabidopsis thaliana planted at the native sites of the parental ecotypes in Italy and Sweden in 2 years. We estimated genetic correlations among fitness components based on genotypic means and explored their causes with QTL mapping. The local ecotype produced more seeds per fruit than did the non-local ecotype, reflected in stronger adaptive differentiation than was previously shown based on survival and fruit number only. Genetic correlations between survival and overall fecundity, and between number of fruits and number of seeds per fruit, were positive, and there was little evidence of a trade-off between seed size and number. Quantitative trait loci for these traits tended to map to the same regions of the genome and showed positive pleiotropic effects. The results indicate that adaptive differentiation between the two focal populations largely reflects the evolution of increased ability to acquire resources in the local environment, rather than shifts in the relative allocation to different life-history traits. Differentiation both in phenology and in tolerance to cold is likely to contribute to the advantage of the local genotype at the two sites.

中文翻译：

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拟南芥的生活史权衡和适应性的遗传基础

分配给生存的资源不能用于增加繁殖力，但这种权衡限制适应的程度取决于整体资源状况。因此，对当地环境条件的适应可能需要特征的进化，从而增加个人可用资源的数量（他们的资源状况或“条件”）。我们研究了在拟南芥重组自交系种群中权衡和条件增加对适应性进化的相对贡献2年内在意大利和瑞典的亲本生态型的原生地种植。我们基于基因型均值估计了适应度成分之间的遗传相关性，并通过 QTL 映射探索了它们的原因。本地生态型比非本地生态型每个果实产生更多的种子，这反映在比之前仅基于存活率和果实数量显示的更强的适应性分化上。存活率和总体繁殖力之间以及果实数量和每个果实的种子数量之间的遗传相关性呈正相关，并且几乎没有证据表明种子大小和数量之间存在权衡。这些性状的数量性状基因座倾向于映射到基因组的相同区域，并显示出积极的多效性。结果表明，两个焦点种群之间的适​​应性分化在很大程度上反映了在当地环境中获取资源能力增强的演变，而不是不同生活史特征的相对分配的变化。物候学和耐寒性的差异可能有助于两个位点的本地基因型的优势。