Cereals are the most important sources of calories and nutrition for the human population, and are an essential animal feed. Food security depends on adequate production and demands are predicted to rise as the global population rises. The need for increased yields will have to be coupled to the efficient use of resources including fertilisers such as nitrogen to underpin the sustainability of food production. Although optimally performing crops with high yields require a balanced mineral nutrition, nitrogen fundamentally drives growth and yield as well as requirements for other nutrients. It is estimated that globally only 33% of applied nitrogen fertiliser is recovered in the harvested grain, indicative of a huge waste of resource and potential major pollutant and is thus a major target for crop improvement. Both agronomy and breeding will contribute to improved nitrogen use efficiency (NUE) and an important component of the latter is harnessing germplasm variation. This review will consider the key traits involved in NUE, the potential to exploit genetic variation for these specific traits, and the approaches to be utilised.

中文翻译：

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利用氮利用效率的遗传变异来改良谷类作物。

谷物是人类最重要的热量和营养来源，也是重要的动物饲料。粮食安全取决于充足的生产，预计需求将随着全球人口的增长而增加。提高产量的需求必须与资源的有效利用相结合，包括氮肥等肥料，以支撑粮食生产的可持续性。尽管高产作物的最佳表现需要均衡的矿物质营养，但氮从根本上推动生长和产量以及对其他营养素的需求。据估计，全球所施用的氮肥只有33%在收获的谷物中被回收，这表明资源的巨大浪费和潜在的主要污染物，因此是作物改良的主要目标。农艺和育种都将有助于提高氮利用效率（NUE），而后者的一个重要组成部分是利用种质变异。本综述将考虑 NUE 涉及的关键性状、利用这些特定性状的遗传变异的潜力以及要使用的方法。