The Effect of Wheat-Rye Substitution on Chromosome Elimination: An Analysis of Univalents' Behavior in Wheat Meiosis with Dimonosomy and Tetramonosomy

The effect of wheat-rye chromosome 1Rv/1A, 2R/2D and 6R/6A substitutions characterized by differences in the expression of the equational division of sister centromeres in anaphase I on segregation and the elimination of wheat and rye univalents was investigated. To determine the individual effect of each of the studied chromosomal pairs, a comparative analysis of the univalent behavior in the meiosis of dimonosomic 1Rv-1A, 2R-2D, 6R-6A and tetramonosomics 1Rv-2R-1A-2D, 1Rv-6R-1A-6A, 2R-6R-2D-6A was con-ducted. 2R/2D substitution was experimentally demonstrated to suppress an equational univalents division, while 6R/6A substitution resulted in high frequency chromosomes' elimination, especially in the meiosis of 2R-6R-2D-6A tetramonosomics. Other meiotic mechanisms, together with the sister chromatids separation at anaphase I, may affect the elimination of the final products of univalent segregation. It was demonstrated that the number and pattern of univalent chromosomal behavior affected hybrid plant fertility.