Genetic Structure in a Core Subset of Cultivated Barley Germplasm

Abstract

ABSTRACTCultivated barley (Hordeum vulgare L. subsp. vulgare) is one of the economically most important cereals with a large number of germplasm accessions conserved worldwide. A core subset of 571barley accessions representing 94 countries was developed, genotyped using 30 informative simple sequence repeat (SSR) markers, and analyzed with several common approaches. The distance‐based analysis of the 230 SSR allele profile revealed a major division of the barley accessions that explained 6 to 8% SSR variation. The model‐based Bayesian analyses revealed six optimal clusters that captured 17.5% SSR variation. The clusters varied in size from 34 to 160, consisted of accessions from many countries and regions, and were well represented by accessions with various important agronomic traits such as kernel row number and growth habit. Such germplasm partitions were further supported from principal component and neighbor‐joining analyses. A mini core subset of 219 accessions from 94 countries was thus developed for future structural inferences. Interestingly, the revealed genetic structure is consistent with the known barley domestication history. Therefore, the inferred optimal clusters may provide the best possible structural description of the current global cultivated barley gene pool and also are useful for future barley research in association mapping, adaptation, and domestication.