麦芽浸出率是指在一定的糖化条件下所抽提的麦芽可溶性物质的总量，其高低直接关系到单位原料能生产啤酒数量的多少，是一个与经济效益密切相关的重要品质指标。前期研究中，我们在2H上鉴定到一个麦芽浸出率主效QTL，解释高达55%表型变异，其紧密连锁为SNP标记4173730S（15.44 cM）。随着大麦基因组的公布，可望通过图位克隆法克隆到该主效QTL/基因。在此基础上，本研究采用Naso Nijo/泰兴9425 组合构建的重组自交系（RILs）和 近等基因系（NILs）群体精细定位并克隆上述麦芽浸出率主效QTL/基因，开发基因标记为育种所用。利用Golden Promise 进行功能互补试验，阐明该主效QTL/基因的作用机制。通过对转基因与非转基因大麦的麦芽品质试验鉴定，进一步揭示该主效QTL/基因对麦芽浸出率的影响。本研究可为大麦优质育种提供理论依据。

Malt extract, the soluble material obtained during malting process, is the most important trait for breeding potential new malting barley varieties. In our previous studies, we identified a major QTL for malt extract, accounting for 55% of the phenotypic variation. This QTL was mapped on 2H in the Naso Nijo/Taixin 9425 barley double haploid population. With the available of barley genome sequence, this QTL/gene can be isolated from map-based cloning. In this project, this major QTL will be fine mapped and candidate gene(s) will be identified using Naso Nijo/Taixin 9425 RILs and NILs populations. Gene markers will be developed for marker assisted selection. Golden Promise transformed with a construct containing-full length this QTL/gene genomic DNA will be used to confirm that this locus is responsible for the malt extract. Meanwhile, the transformed and non-transformed barley lines will be determined for their malting qualities, which will demonstrate its association between the QTL/gene and malt extract. The outcome of the project will hopefully provide the theoretical basis for malting barley breeding.