Association Mapping of Diastatic Power in UK Winter and Spring Barley by Exome Sequencing of Phenotypically Contrasting Variety Sets.

Diastatic Power (DP) is an important quality trait for malt used in adjunct brewing and distilling. Substantial genetic variation for DP exists within UK elite barley cultivars, but breeding progress has been slow due to the limited demand, compared to the overall barley market, and difficulties in assessing DP. Estimates of DP (taken from recommended and national list trials between 1994 and 2012) from a collection of UK elite winter and spring varieties were used to identify contrasting sets of high and low DP varieties. DNA samples were pooled within sets and exome capture sequencing performed. Allele frequency estimates of Single Nucleotide Polymorphisms (SNPs) identified from the sequencing were used to identify genomic locations associated with differences in DP. Individual genotypes were generated from a set of custom KASP assays, both within sets and in a wider germplasm collection, to validate allele frequency estimates and marker associations with DP. QTL identified regions previously linked to variation in DP as well as novel associations. QTL colocalised with a number of genes annotated as having a diastase related function. Results indicate that winter barley is more genetically diverse for genes influencing DP. The marker assays produced by this work represent a resource that is available for immediate use by barley breeders in the production of new high DP varieties.

糖化力（DP）是用于辅料酿造和蒸馏的麦芽的一项重要品质特性。英国优良大麦品种内存在大量糖化力的遗传变异，但由于与整个大麦市场相比需求有限，且糖化力评估困难，育种进展缓慢。对英国优良冬、春大麦品种集合的糖化力估计值（取自1994年至2012年间的推荐品种试验和国家品种名录试验）被用于确定高糖化力和低糖化力品种的对比组。在组内对DNA样本进行混合，并进行外显子组捕获测序。利用测序确定的单核苷酸多态性（SNP）的等位基因频率估计值来确定与糖化力差异相关的基因组位置。从一组定制的KASP分析中生成个体基因型，包括在组内以及更广泛的种质集合中，以验证等位基因频率估计值以及标记与糖化力的关联。数量性状基因座（QTL）确定了先前与糖化力变异相关的区域以及新的关联。QTL与一些标注为具有淀粉酶相关功能的基因共定位。结果表明，冬大麦在影响糖化力的基因方面具有更多的遗传多样性。这项工作所产生的标记分析是一种可供大麦育种者在培育新的高糖化力品种时立即使用的资源。