Genetic evidence for modern reticulate microevolution in mixed populations of Elymus uralensis, E. viridiglumis, E. mutabilis, and E. caninus (Poaceae) in the Southern Urals

The article considers microevolutionary relationships of Elymus species common in the Southern Urals. The objectives were to trace genetic links between E. uralensis and E. viridiglumis described from closely located habitats and to assess the possibility of introgression of E. uralensis with E. mutabilis and E. caninus during joint growth. ISSR DNA analysis was used to identify genotypes. The use of six ISSR primers showed the presence of multiple reticulate microevolutions in mixed populations of Elymus species in the Southern Urals. This process is based on periodic spontaneous hybridization with subsequent interspecific introgression. According to the specificity of ISSR profiles, the endemic species E. uralensis showed no relationship with the Siberian group of E. komarovii – E. transbaicalensis – E. margaritae species. The objective was to identify reproductive compatibility between the species E. uralensis, E. viridiglumis, E. mutabilis, and E. caninus of the Southern Urals, to trace the dynamics of seed fertility and recombination of diagnostic traits in hybrids in the F1–F3 generations. In seven crossbreeding combinations, F1 hybrids were created that produced full grains. This fact indicates the absence of strict reproductive isolation of E. uralensis from other species growing together with it. Modeling the introgression process under experimental conditions showed the possibility of stabilizing the seed fertility of hybrids in subsequent generations. As a result of hybridization, a set of recombinant morphotypes was formed that combined trait of different species. Based on the analysis of hybrid segregation by marker traits, it is possible to assume the origin of the species E. uralensis and E. viridiglumis of the Southern Urals with the participation of local ancestral biotypes E. caninus and E. mutabilis.