Doubled-haploid libraries from landraces capture native genetic diversity for a multitude of quantitative traits and make it accessible for breeding and genome-based studies. Maize landraces comprise large allelic diversity. We created doubled-haploid (DH) libraries from three European flint maize landraces and characterized them with respect to their molecular diversity, population structure, trait means, variances, and trait correlations. In total, 899 DH lines were evaluated using high-quality genotypic and multi-environment phenotypic data from up to 11 environments. The DH lines covered 95% of the molecular variation present in 35 landraces of an earlier study and represent the original three landrace populations in an unbiased manner. A comprehensive analysis of the target trait plant development at early growth stages as well as other important agronomic traits revealed large genetic variation for line per se and testcross performance. The majority of the 378 DH lines evaluated as testcrosses outperformed the commercial hybrids for early development. For total biomass yield, we observed a yield gap of 15% between mean testcross yield of the commercial hybrids and mean testcross yield of the DH lines. The DH lines also exhibited genetic variation for undesirable traits like root lodging and tillering, but correlations with target traits early development and yield were low or nonsignificant. The presented diversity atlas is a valuable, publicly available resource for genome-based studies to identify novel trait variation and evaluate the prospects of genomic prediction in landrace-derived material.

中文翻译：

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欧洲玉米地方品种可用于植物育种和基于基因组的研究。

来自地方品种的双单倍体文库捕获了多种数量性状的天然遗传多样性，并使其可用于育种和基于基因组的研究。玉米地方品种包含大量的等位基因多样性。我们从三个欧洲燧石玉米地方品种中创建了双单倍体 (DH) 文库，并对其分子多样性、群体结构、性状均值、方差和性状相关性进行了表征。总共使用来自多达 11 个环境的高质量基因型和多环境表型数据评估了 899 个 DH 系。DH 系覆盖了早期研究中 35 个地方品种中存在的 95% 的分子变异，并以公正的方式代表了原始的三个地方品种种群。对早期生长阶段目标性状植物发育以及其他重要农艺性状的综合分析揭示了品系本身和测交性能的巨大遗传变异。作为测试杂交评估的 378 个 DH 品系中的大多数在早期发育方面优于商业杂交品系。对于总生物量产量，我们观察到商业杂交种的平均测交产量与 DH 品系的平均测交产量之间存在 15% 的产量差距。DH品系还表现出不良性状的遗传变异，如根倒伏和分蘖，但与早期发育和产量目标性状的相关性较低或不显着。所提出的多样性图谱是基于基因组的研究的宝贵的公开资源，可用于识别新的性状变异并评估地方品种来源材料的基因组预测的前景。