Malt extract is the most relevant parameter describing malting quality in barley. The observed differences in malt extract from crops grown in different environments are complex to explain, and their interpretation might represent an opportunity to improve malting quality for barley crops grown under field conditions. Although the effect of some grain attributes on malt extract are overall known (e.g. protein content and grain size) other are less understood and are complex to replicate across experiments, with few evidence of how they are controlled by the environment during grain filling (e.g. hordeins and pasting properties). Four commercial malting barley cultivars were sown on eleven sowing dates across four years to explore a wide range of thermal conditions during grain filling. Contrasting nitrogen availabilities were included to promote variability in the protein content. Grain plumpness, protein content, pasting temperature, and the amount of d- and γ-hordeins showed a significant effect on malt extract. Protein content showed a negative effect on malt extract only when it was above a threshold value of ca. 10 %, although that threshold varied between cultivars. Pasting temperature presented a significant interaction with protein content. d-hordein showed a negative effect on malt extract only when the protein content was below the threshold, explaining some of the contradictory results reported in the literature. Evidence of a negative effect of γ-hordeins on malt extract was found as well. The period between pollination and physiological maturity was arbitrarily divided into thermal-time intervals, and correlation analyses were performed between mean temperature during each period and the grain attributes affecting malt extract. For all the cultivars, only two attributes were found to be modulated by the thermal environment explored by the crop during grain filling: pasting temperature was positively correlated to the mean temperature explored by the crop during the middle of grain filling, whereas grain plumpness was negatively correlated with the mean temperature during the second half of grain filling. Quantitative models reported in the present study in addition to offering an explanation of how malting quality is shaped in the field, constitute a useful tool for agro-climatic zoning for the suitability of high-quality malting barley production.

麦芽提取物是描述大麦麦芽质量的最相关参数。观察到的来自不同环境下种植的作物的麦芽提取物的差异很难解释，它们的解释可能代表了提高在田间条件下种植的大麦作物的麦芽质量的机会。尽管一些谷物属性对麦芽提取物的影响是众所周知的（例如蛋白质含量和谷物大小），但其他一些则鲜为人知，并且在整个实验中复制起来很复杂，几乎没有证据表明它们在谷物灌浆过程中如何受环境控制（例如大麦醇溶蛋白）和粘贴属性）。四个商业麦芽大麦品种在四年中的十一个播种日期播种，以探索谷物灌浆过程中的各种热条件。包括对比氮可用性以促进蛋白质含量的可变性。谷物丰满度、蛋白质含量、糊化温度和用量d - 和 γ-大麦醇溶蛋白对麦芽提取物显示出显着影响。仅当蛋白质含量高于约阈值时，蛋白质含量才会对麦芽提取物产生负面影响。10 %，尽管该阈值因品种而异。糊化温度与蛋白质含量有显着的相互作用。d只有当蛋白质含量低于阈值时，-大麦醇溶蛋白才会对麦芽提取物产生负面影响，这解释了文献中报道的一些相互矛盾的结果。还发现了γ-大麦醇溶蛋白对麦芽提取物的负面影响的证据。将授粉和生理成熟之间的时间任意划分为热时间间隔，并在每个时间段的平均温度与影响麦芽提取物的谷物属性之间进行相关分析。对于所有品种，只有两个属性受灌浆期间作物探索的热环境调节：糊化温度与灌浆中期作物探索的平均温度呈正相关，而籽粒饱满度与籽粒灌浆后半期的平均温度呈负相关。本研究中报告的定量模型除了提供对麦芽质量如何在田间形成的解释之外，还构成了一个有用的工具，用于对高质量麦芽大麦生产的适宜性进行农业气候分区。