Developing novel types of low protein wheat for breadmaking

氮肥对维持小麦产量至关重要，但也是粮食品质的重要决定因素。这是因为谷物蛋白质的合成需要氮，面筋蛋白形成了主要的谷物蛋白质部分。英国生产的小麦中约有40%用于食品生产，尤其是制作面包和其他烘焙产品。小麦也被广泛用作许多加工食品的功能性成分，而面包小麦和进口硬粒小麦分别用于制作面条和意大利面。面筋蛋白对这些用途至关重要，为面团提供粘弹性。因此，谷物蛋白质的含量和质量会影响加工质量，在英国，超过80%的“工厂生产”面包使用的Chorleywood面包制作工艺（CBP）规定了至少13%的谷物蛋白质含量。生产面包用小麦对氮的需要量也高于产量的最佳需要量，农民可在最佳产量之上施用50 kg N/Ha，以达到13%的蛋白质（2.28%氮）。这是昂贵的，因为氮肥对作物生产有很大的贡献，也可能导致农业环境中更大的“氮足迹”。通过优化小麦植株对氮的吸收和利用效率，有可能在一定程度上减少对面包用小麦的需求。然而，这只会带来有限的好处，一个更可行的长期解决方案是开发新型小麦和加工系统，这将允许使用蛋白质含量较低的小麦制作面包。因此，我们将确定在低谷物蛋白质条件下具有良好和稳定的面包制作质量的小麦类型。对该性状的遗传分析将为小麦育种者提供分子标记，而对基础机制的研究将允许使用新的选择程序来识别种质并在育种计划中进行质量选择。我们还将与磨坊主和面包师合作，确定加工蛋白质含量较低的小麦的最佳条件。

Nitrogen fertiliser is essential to sustain wheat yields but is also an important determinant of grain quality. This is because nitrogen is required for the synthesis of grain proteins, with the gluten proteins forming the major grain protein fraction. About 40% of the wheat produced in the UK is used for food production, particularly for making bread and other baked products. Wheat is also widely used as a functional ingredient in many processed foods, while bread wheat and imported durum wheats are used to make noodles and pasta, respectively. The gluten proteins are essential for these uses, providing visco-elastic properties to dough. Consequently, the content and quality of the grain proteins affect the processing quality, with a minimum of 13% being specified for the Chorleywood Breadmaking Process (CBP) which is used for over 80% of the "factory produced" bread in the UK. The requirement of nitrogen to produce wheat for bread making is also above the optimum required for yield, and farmers may apply up to 50 kg N/Ha above the yield optimum to achieve 13% protein (2.28% N). This is costly with nitrogen fertiliser contributing significantly to crop production, and may also contribute to a greater "nitrogen footprint" in the farmed environment. It may be possible to reduce the requirement for breadmaking wheats, to a limited extent, by optimising the efficiency of nitrogen uptake and use within the wheat plant. However, this will only have limited benefits and a more viable long-term solution is to develop new types of wheat and processing systems which will allow the use of lower protein contents for bread making. We will therefore identify types of wheat which have good and stable breadmaking quality at low grain protein. Genetic analyses of the trait will provide molecular markers to assist wheat breeders while studies of underpinning mechanisms will allow new selection procedures to be used to identify germplasm and select for quality in breeding programmes. We will also work with millers and bakers to establish optimum conditions for processing of wheats with lower protein contents.