Allelic Variation of High-Molecular-Weight Glutenin Genes in <i>Triticum</i> Species and Triticale (× <i>Triticosecale</i> Wittmack)

Abstract

High-molecular-weight glutenin subunits (HMW-GS) encoded by alleles at the &lt;em&gt;Glu-A1&lt;/em&gt;, &lt;em&gt;Glu-B1&lt;/em&gt;, and &lt;em&gt;Glu-D1&lt;/em&gt; loci confer unique bread-making properties of common wheat (&lt;em&gt;Triticum aestivum&lt;/em&gt; L.). The identification of HMW-GS is the prerequisite for pyramiding high-quality glutenin genes. The present review is designed to list all published HMW-GS alleles in &lt;em&gt;Triticum&lt;/em&gt; species and triticale (A- and B genomes), focusing on methods for their identification. &lt;em&gt;T. monococcum&lt;/em&gt; is characterized by 37 alleles at the &lt;em&gt;Glu-1&lt;/em&gt; locus versus four alleles in &lt;em&gt;T. thaoudar&lt;/em&gt; and 39 in &lt;em&gt;T. urartu&lt;/em&gt;. In total, 80 alleles at &lt;em&gt;Glu-A1&lt;/em&gt; of diploid &lt;em&gt;Triticum&lt;/em&gt; species and about 42 alleles found in polyploid wheat landraces and varieties (4x and 6x), including triticale, were listed. Allelic variation at the &lt;em&gt;Glu-B1&lt;/em&gt; locus is divided into 3 groups: &lt;em&gt;a&lt;/em&gt; – &lt;em&gt;z&lt;/em&gt;, &lt;em&gt;aa&lt;/em&gt; – &lt;em&gt;az&lt;/em&gt;, and &lt;em&gt;ba&lt;/em&gt; – &lt;em&gt;ct&lt;/em&gt;, comprising 121 alleles, of which 26 subunits have unspecified alleles. At least 51 allelic variants at locus &lt;em&gt;Glu-D1&lt;/em&gt; of &lt;em&gt;Triticum&lt;/em&gt; species were indicated, along with carriers of the species level. In addition, subunit-specific genetic loci have been tagged, facilitating molecular marker development of high-gluten wheat cultivars through marker-assisted breeding.