Genome ploidy and mating system in the population of Thynopyrum intermedium

Thinopyrum intermedium, a wild wheat relative, for some reasons is on interest for its involvement to the introgressive hybridization with wheat. The basis for the purposeful work in this direction should be the information about the biological and genetic properties of the species, including the mating system. The mating system can be identified based on the genotyping of plants in populations for a polymorphic gene with codominant inheritance. Gene Glu was used as such a codominant gene. Methods. Cytological (determination of the chromosome number in metaphases of mitosis), electrophoresis of glutenin storage proteins, comparative analysis of electrophoretic spectra, and the population genetic methods for calculating the frequencies of genes and genotypes. Results. Plants were hexaploid, with 2n = 42 chromosomes. In a sample of fifty plants, a genetic control of components of the glutenin spectra has been established. They are controlled by three independent genes: Glu-Thi1-2 with four alleles 1-2 (cluster), 1, 2, 0, Glu-Thi1-4 withfour alleles 1-4 (cluster), 1, 4, 0, and the three-allele gene Glu-Thi1-3-5. The participation of the three genes in the formation of the electrophoretic spectrum of glutenins is consistent with the hexaploid nature of Thinopyrum intermedium, which follows from the established number of 42 chromosomes. The information about the genetic control of glutenins is the basis for determining the mating system of this species. A simplified three-allele model of genetic control of glutenins’ electrophoretic spectra was used for determination of the mating system of Thinopyrum intermedium. Conclusions. Plants of the studied Thinopyrum intermedium population have a mixed mating system and the probability of self-pollination ranging from 0,50 to 0,81, depending on the Glu gene, which is used for determination of heterozygosity of the plants. This biological characteristic is positive for prospective use of this species for wide hybridization.