We identify the largest amount of QTLs for cold tolerance in maize; mainly associated with photosynthetic efficiency, which opens new possibilities for genomic selection for cold tolerance in maize. Breeding for cold tolerance in maize is an important objective in temperate areas. The objective was to carry out a highly efficient study of quantitative trait loci (QTLs) for cold tolerance in maize. We evaluated 406 recombinant inbred lines from a multi-parent advanced generation intercross (MAGIC) population in a growth chamber under cold and control conditions, and in the field at early and normal sowing. We recorded cold tolerance-related traits, including the number of days from sowing to emergence, chlorophyll content and maximum quantum efficiency of photosystem II (Fv/Fm). Association mapping was based on genotyping with near one million single nucleotide polymorphism (SNP) markers. We found 858 SNPs significantly associated with all traits, most of them under cold conditions and early sowing. Most QTLs were associated with chlorophyll and Fv/Fm. Many candidate genes coincided between the current research and previous reports. These results suggest that (1) the MAGIC population is an efficient tool for identifying QTLs for cold tolerance; (2) most QTLs for cold tolerance were associated with Fv/Fm; (3) most of these QTLs were located in specific genomic regions, particularly bin 10.04; (4) the current study allows genetically improving cold tolerance with genome-wide selection.

中文翻译：

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剖析多亲玉米群体中耐寒性的遗传学。

我们确定了玉米耐寒性的最大数量的 QTL；主要与光合效率有关，这为玉米耐寒性的基因组选择开辟了新的可能性。玉米耐寒性育种是温带地区的一个重要目标。目的是对玉米耐寒性的数量性状基因座 (QTL) 进行高效研究。我们在低温和对照条件下的生长室中以及在早期和正常播种的田间中评估了来自多亲上代杂交 (MAGIC) 种群的 406 个重组自交系。我们记录了耐寒性相关性状，包括从播种到出苗的天数、叶绿素含量和光系统 II 的最大量子效率 (Fv/Fm)。关联作图基于具有近一百万个单核苷酸多态性 (SNP) 标记的基因分型。我们发现 858 个 SNP 与所有性状显着相关，其中大多数在寒冷条件和早播条件下。大多数 QTL 与叶绿素和 Fv/Fm 相关。许多候选基因在当前的研究和以前的报告之间重合。这些结果表明 (1) MAGIC 群体是鉴定耐寒性 QTL 的有效工具；(2)大多数耐寒性QTL与Fv/Fm相关；(3) 这些QTL大部分位于特定的基因组区域，尤其是bin 10.04；(4) 目前的研究允许通过全基因组选择从遗传上提高耐寒性。大多数在寒冷条件下和早播。大多数 QTL 与叶绿素和 Fv/Fm 相关。许多候选基因在当前的研究和以前的报告之间重合。这些结果表明 (1) MAGIC 群体是鉴定耐寒性 QTL 的有效工具；(2)大多数耐寒性QTL与Fv/Fm相关；(3) 这些QTL大部分位于特定的基因组区域，尤其是bin 10.04；(4) 目前的研究允许通过全基因组选择从遗传上提高耐寒性。大多数在寒冷条件下和早播。大多数 QTL 与叶绿素和 Fv/Fm 相关。许多候选基因在当前的研究和以前的报告之间重合。这些结果表明 (1) MAGIC 群体是鉴定耐寒性 QTL 的有效工具；(2)大多数耐寒性QTL与Fv/Fm相关；(3) 这些QTL大部分位于特定的基因组区域，尤其是bin 10.04；(4) 目前的研究允许通过全基因组选择从遗传上提高耐寒性。(2)大多数耐寒性QTL与Fv/Fm相关；(3) 这些QTL大部分位于特定的基因组区域，尤其是bin 10.04；(4) 目前的研究允许通过全基因组选择从遗传上提高耐寒性。(2)大多数耐寒性QTL与Fv/Fm相关；(3) 这些QTL大部分位于特定的基因组区域，尤其是bin 10.04；(4) 目前的研究允许通过全基因组选择从遗传上提高耐寒性。