Chromosomal Location of the b-Amy-A1 Gene and Distribution of Its Alleles in Winter Common Wheat Culture

The analysis of the chromosomal location of the b-Amy-A1 gene, which controls the synthesis of wheat beta-amylase isoenzymes, was carried out by assessing the linkage with the B1 (Awnless) marker gene located in the long arm of chromosome 5A. Results based on F₂ and F_→∞ Delta × Selection 2092 study. The b-Amy-A1 locus showed 6.55 ± 2.10% linkage to the B1 gene. In parallel, alleles of the Rht8 locus, which causes dwarfing of plants, were identified and its linkage to the C gene (Compact spike) was established in 22.59 ± 6.28% (F₂) and 24.22 ± 1.18% (F_→∞) of recombination in chromosome 2D. The Delta variety carries the Rht8a allele, and the Selection 2092 accession carries the Rht8c allele. A collection of winter common wheat varieties created and released in the Russia was studied. The selected cultivars carried identical b-Amy-B1a and b-Amy-D1a alleles of the 4B and 4D chromosome loci. At the same time, the most common b-Amy-A1a and b-Amy-A1b alleles of chromosome 5A differed. It was found that in the direction from south to north of European part, the frequency of the b-Amy-A1a allele increases from 24.2% (Northern Caucasus) to 72.50% (Moscow–Ulyanovsk regions). Accordingly, the frequency of the alternative allele b-Amy-A1b decreased from 75.8% (Northern Caucasus) to 25.0% (Moscow–Ulyanovsk regions). In the Rostov region, the ratio of the occurrence of alleles b-Amy-A1a to b-Amy-A1b was 42.5 to 57.5%. At the same time, already in the Central Chernozem region⁺, a significant dominance of the b-Amy-A1a allele over b-Amy-A1b was manifested. Using the collection of varieties as a population of F_→∞ demonstrated the linkage of b-Amy-A1 with B1 value in 5.56 ± 1.90% recombination.