Data from: Phenotypic landscapes: phenological patterns in wild and cultivated barley

Phenotypic variation in natural populations is the outcome of the joint effects of environmentally induced adaptations and neutral processes on the genetic architecture of quantitative traits. In this study we examined the role of adaptation in shaping wild barley phenotypic variation along different environmental gradients. Detailed phenotyping of 164 wild barley (Hordeum spontaneum) accessions from Israel (of the Barley1K collection), and 18 cultivated barley (H. vulgare) varieties, was conducted in common garden field trials. Cluster analysis based on phenotypic data indicated that wild barley in this region can be differentiated into three ecotypes in accordance with their ecogeographic distribution: north, coast, and desert. Population differentiation (Qst) for each trait was estimated using a hierarchical Bayesian model and compared to neutral differentiation (Fst) based on 42 microsatellite markers. This analysis indicated that the three clusters diverged in morphological but not in reproductive characteristics. To address the issue of phenotypic variation along environmental gradients, climatic and soil gradients were compared with each of the measured traits given the geographical distance between sampling sites using a partial Mantel test. Flowering time and plant growth were found to be differentially correlated with climatic and soil characteristic gradients, respectively. The H. vulgare varieties were superior to the H. spontaneum accessions in yield components yet resembled the Mediterranean types in vegetative characteristics and flowering time, which may indicate the geographic origin of domesticated barley.

自然种群的表型变异，是环境诱导的适应性演化与中性过程共同作用于数量性状（quantitative traits）遗传架构的结果。本研究探究了适应性在野生大麦（Hordeum spontaneum）沿不同环境梯度的表型变异塑造过程中所发挥的作用。我们针对来自以色列的164份野生大麦种质（隶属于Barley1K种质库）以及18份栽培大麦（H. vulgare）品种，在同质园田间试验中开展了详细的表型鉴定工作。基于表型数据的聚类分析结果显示，该区域的野生大麦可依据其生态地理分布划分为三类生态型（ecotype）：北部生态型、沿海生态型与荒漠生态型。本研究采用分层贝叶斯模型（hierarchical Bayesian model）估算各性状的种群分化系数（Qst），并基于42个微卫星标记（microsatellite markers）计算中性分化系数（Fst）以进行对比分析。分析结果表明，这三个聚类群在形态性状上存在显著分化，但生殖性状并无明显差异。为解析沿环境梯度的表型变异规律，本研究结合采样点间的地理距离，通过偏曼特尔检验（partial Mantel test）比较了气候梯度、土壤梯度与各测定性状之间的关联。研究发现，开花时间与气候梯度呈现显著相关，而植株生长性状则分别与土壤特征梯度存在差异化关联。栽培大麦品种在产量构成因子方面优于野生大麦种质，但在营养生长性状与开花时间上与地中海类群较为相似，这一结果或可揭示驯化大麦的地理起源。