Allelic diversity of hordein-coding loci Hrd A and Hrd B in cultivated (Hordeum vulgare L.) and wild (H. spontaneum C. Koch) barley from Iran (as a part of the Fertile Crescent)

Abstract

Polymorphism of hordeins encoded by the Hrd A and Hrd B loci was studied using starch gel electrophoresis in 63 landraces of cultivated barley (H. vulgare) and 43 accessions of wild barley (H. spontaneum) from Iran. We identified 35 and 32 Hrd A alleles of H. vulgare and H. spontaneum. The number of Hrd B alleles in these species was 55 and 48, respectively. The frequencies of alleles in the Hrd A and Hrd B loci in cultivated barley varied within the range of 0.0016–0.2816 (Hrd A) and 0.0016–0.1221 (Hrd B). The allelic frequencies in wild barley ranged within 0.0077–0.2170 and 0.0077–0.0815, respectively. Iranian accessions of H. spontaneum and H. vulgare shared some alleles; the number of common alleles was seven for the Hrd A locus and five for the Hrd B locus. These alleles were detected mainly in accessions of wild barley heterozygous or heterogenic for hordein-coding loci. We concluded that the regions close to Zagros mountain range cannot be considered as a barley domestication center. At the same time, Iranian H. spontaneum could have donated some hordein-coding loci to H. vulgare as a result of introgressions occurring because of spontaneous hybridization over the course of the spread of cultivated barley.