Berlin Sofia, Hallingbäck Henrik R, Beyer Friderike, Nordh Nils-Erik, Weih Martin, Rönnberg-Wästljung Ann-Christin
Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, P.O. Box 7080, SE-750 07 Uppsala, Sweden.
Swedish University of Agricultural Sciences, Department of Crop Production Ecology, Linnean Centre for Plant Biology, P.O. Box 7043, SE-750 07 Uppsala, Sweden.
Ann Bot. 2017 Jul 1;120(1):87-100. doi: 10.1093/aob/mcx029.
Phenotypic plasticity can affect the geographical distribution of taxa and greatly impact the productivity of crops across contrasting and variable environments. The main objectives of this study were to identify genotype-phenotype associations in key biomass and phenology traits and the strength of phenotypic plasticity of these traits in a short-rotation coppice willow population across multiple years and contrasting environments to facilitate marker-assisted selection for these traits.
A hybrid Salix viminalis × ( S. viminalis × Salix schwerinii ) population with 463 individuals was clonally propagated and planted in three common garden experiments comprising one climatic contrast between Sweden and Italy and one water availability contrast in Italy. Several key phenotypic traits were measured and phenotypic plasticity was estimated as the trait value difference between experiments. Quantitative trait locus (QTL) mapping analyses were conducted using a dense linkage map and phenotypic effects of S. schwerinii haplotypes derived from detected QTL were assessed.
Across the climatic contrast, clone predictor correlations for biomass traits were low and few common biomass QTL were detected. This indicates that the genetic regulation of biomass traits was sensitive to environmental variation. Biomass QTL were, however, frequently shared across years and across the water availability contrast. Phenology QTL were generally shared between all experiments. Substantial phenotypic plasticity was found among the hybrid offspring, that to a large extent had a genetic origin. Individuals carrying influential S. schwerinii haplotypes generally performed well in Sweden but less well in Italy in terms of biomass production.
The results indicate that specific genetic elements of S. schwerinii are more suited to Swedish conditions than to those of Italy. Therefore, selection should preferably be conducted separately for such environments in order to maximize biomass production in admixed S. viminalis × S. schwerinii populations.
表型可塑性会影响分类群的地理分布，并极大地影响作物在不同且多变环境中的生产力。本研究的主要目的是确定短轮伐期矮林柳树群体中关键生物量和物候性状的基因型-表型关联，以及这些性状在多年和不同环境下表型可塑性的强度，以促进这些性状的标记辅助选择。
一个由463个个体组成的杂交柳（Salix viminalis × (S. viminalis × Salix schwerinii)）群体进行了无性繁殖，并种植在三个共同园试验中，其中一个是瑞典和意大利之间的气候对比试验，另一个是意大利的水分可利用性对比试验。测量了几个关键的表型性状，并将表型可塑性估计为不同试验间的性状值差异。利用密集连锁图谱进行数量性状位点（QTL）定位分析，并评估检测到的QTL衍生的S. schwerinii单倍型的表型效应。
在气候对比试验中，生物量性状的克隆预测相关性较低，且检测到的常见生物量QTL较少。这表明生物量性状的遗传调控对环境变异敏感。然而，生物量QTL在多年间以及水分可利用性对比试验中经常共享。物候QTL通常在所有试验中共享。在杂交后代中发现了显著的表型可塑性，且在很大程度上具有遗传起源。携带具有影响力的S. schwerinii单倍型的个体在瑞典的生物量生产方面通常表现良好，但在意大利则表现较差。
结果表明，S. schwerinii的特定遗传元件更适合瑞典的条件，而不是意大利的条件。因此，为了使混交的S. viminalis × S. schwerinii群体中的生物量产量最大化，最好针对此类环境分别进行选择。
