BACKGROUND AND AIMS Manganese (Mn) deficiency in barley is a global problem. It is difficult to detect in the early stages of symptom development and is commonly pre-emptively corrected by Mn foliar sprays that can be costly. Landraces adapted to marginal lands around the world represent a genetic resource for potential sustainability traits including mineral use efficiency. This research aims to confirm novel Mn use efficiency traits from the Scottish landrace Bere and use an association mapping approach to identify genetic loci associated with the trait. METHODS A hydroponic system was developed to identify and characterise the Mn deficiency tolerance traits in a collection of landraces, including a large number of Scottish Bere barleys, a group of 6-rowed heritage landraces grown in the highlands and islands of Scotland. Measuring chlorophyll fluorescence, the effect of Mn deficiency was identified in the early stages of development. Genotypic data, generated using the 50k Illumina iSelect genotyping array, was coupled with the Mn phenotypic data to create a genome-wide association study (GWAS) identifying candidate loci associated with Mn use efficiency. KEY RESULTS The Bere lines generally had good Mn use efficiency traits. Individual Bere lines showed large efficiencies, with some Bere lines recording almost double chlorophyll fluorescence readings in limited Mn conditions compared to the elite cultivar Scholar. The Mn efficient Bere lines had increased accumulation of Mn in their shoot biomass compared with elite cultivars, which was highly correlated to the chlorophyll fluorescence. Several candidate genes were identified as being associated with Mn use efficiency in the GWAS. CONCLUSIONS Several genomic regions for Mn use efficiency traits originating from the Bere lines were identified. Further examination and validation of these regions should be undertaken to identify candidate genes for future breeding for marginal lands.

中文翻译：

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评估苏格兰大麦地方品种 Bere (Hordeum vulgare L.) 锰利用效率性状的变异

背景和目的 大麦中的锰 (Mn) 缺乏是一个全球性问题。在症状发展的早期阶段很难检测到，通常可以通过昂贵的锰叶面喷洒来预先纠正。适应世界各地边缘土地的地方品种代表了包括矿物利用效率在内的潜在可持续性特征的遗传资源。本研究旨在确认苏格兰地方品种 Bere 的新型锰利用效率性状，并使用关联作图方法来识别与该性状相关的遗传位点。方法开发了一种水培系统来识别和表征一系列地方品种的锰缺乏耐受性特征，包括大量苏格兰 Bere 大麦，一组生长在苏格兰高地和岛屿的 6 行传统地方品种。测量叶绿素荧光，在发育的早期阶段就确定了缺锰的影响。使用 50k Illumina iSelect 基因分型阵列生成的基因型数据与 Mn 表型数据相结合，创建了一项全基因组关联研究 (GWAS)，用于识别与 Mn 使用效率相关的候选位点。主要结果 Bere 品系通常具有良好的锰利用效率特性。单个 Bere 品系显示出很高的效率，与精英品种 Scholar 相比，一些 Bere 品系在有限的锰条件下记录了几乎两倍的叶绿素荧光读数。与优良品种相比，Mn 高效 Bere 系在其芽生物量中的 Mn 积累增加，这与叶绿素荧光高度相关。在 GWAS 中，几个候选基因被确定为与锰利用效率相关。结论 鉴定了几个源自 Bere 品系的锰利用效率性状的基因组区域。应该对这些区域进行进一步的检查和验证，以确定未来边缘土地育种的候选基因。