Genetic analysis of gliadin-encoding genes reveals gene clusters as well as single remote genes.

Analysis of F2 grains from two different crosses has revealed a complex organization of the family of gliadin-coding genes located on chromosomes of the first homoeological group in hexaploid wheat. Chromosome 1A of variety 'Bezenchukskaya 98' was found to carry at least five gliadin-coding genes of which three genes form a cluster controlling the synthesis of the GLD1A1 block. Two additional genes are located on the both sides of this cluster and recombine with it at frequencies of 5±1.3% and 13±2.9%. Gliadinencoding genes recombining with the main clusters were also found on chromosomes 1B and 1A in the 'Bezenchukskaya 98' and 'Saratovskaya 210' varieties, respectively. In 'Chinese Spring', widely used in genetic studies, we discovered a recombination between genes located on chromosome 1A and controlling the synthesis of ω- and γ-gliadins. Varieties and biotypes of one variety may differ by the presence or absence of such "selfish" (not included in clusters) gliadin components. The similarity of organization of prolamine-coding genes on chromosomes in different cereals is considered.