Germplasm collections of major crops include thousands of accessions whose agronomic evaluation is prevented by high costs, while their molecular characterization is getting increasingly affordable. This study aimed to assess the consistency between alfalfa ( Medicago sativa L.) landrace diversity measures relative to adaptation pattern, eleven morphophysiological traits, and four genotyping strategies using SSR or genotyping-by-sequencing (GBS) SNP markers recorded on either five individual plants or three bulks of 100 plants each per accession. We focused on eleven landraces from Northern Italy featuring large genotype × environment interaction for biomass yield across environments with contrasting level of summer drought. We recorded 34 SSR and 237 SNP polymorphic markers for individual plants, and 41 SSR and 1274 SNP markers for bulked plants. Landrace diversity based on SNP data from bulked plants was the only molecular diversity measure associated with both adaptive diversity as expressed by pattern analysis ( r = 0.34) and drought stress at collecting sites ( r = 0.50). No molecular diversity measure was associated with overall morphophysiological diversity. Molecular diversity was highly consistent only between SSR and SNP data from bulked plants ( r = 0.67). SSR-based diversity from individual plants exhibited marked inconsistency with other molecular diversity measures but was useful for genetic structure assessment, indicating much smaller among-population variation relative to within-population variation (7.5% in terms of variance ratio; 7.8% as global F ST ). Moderate inferences on germplasm adaptive diversity may be achieved by molecular characterization that maximizes the sampling of genomic areas and genotypes within accession through GBS applied to bulked plants.

中文翻译：

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推断种质种质形态生理和适应性多样性的分子多样性评估策略：苜蓿案例研究

主要作物的种质收集包括数以千计的种质，其农艺评价因高成本而受阻，而它们的分子表征越来越负担得起。本研究旨在评估紫花苜蓿 (Medicago sativa L.) 地方品种多样性测量与适应模式、11 个形态生理特征和使用 SSR 或基因分型测序 (GBS) SNP 标记的四种基因分型策略之间的一致性。或三批，每批 100 株植物。我们专注于来自意大利北部的 11 种地方品种，这些品种具有大基因型 × 环境相互作用，用于跨环境的生物量产量与夏季干旱水平的对比。我们记录了单个植物的 34 个 SSR 和 237 个 SNP 多态性标记，以及散装植物的 41 个 SSR 和 1274 个 SNP 标记。基于来自散装植物的 SNP 数据的地方品种多样性是唯一与适应性多样性相关的分子多样性测量，如模式分析 (r = 0.34) 和收集地点的干旱胁迫 (r = 0.50)。没有任何分子多样性测量与整体形态生理多样性相关。分子多样性仅在来自散装植物的 SSR 和 SNP 数据之间高度一致 (r = 0.67)。来自单个植物的基于 SSR 的多样性表现出与其他分子多样性测量的明显不一致，但对遗传结构评估很有用，表明相对于种群内变异，种群间变异要小得多（方差比为 7.5%；作为全局 F 为 7.8%英石 ）。