THE ROLE OF CHROMOSOMES OF THE 5TH HOMOEO LOGOUS GROUP OF WHEAT AND RYE IN THE CONTROL OF EQUATIONAL DIVISION OF UNIVALENTS

A cytological study of meiosis was performed in aneuploid forms of whe at, Triticum aestivum L. (Cv. Saratovskaya 29), and wheat-rye substitu tion lines (Saratovskaya 29-Onokhoiskaya), which had differences both in the number and in the set of chromosomes from the fifth homoeologou s group of genomes ADR. The lines were also significantly different in the frequency of equational divisions of univalents in meiotic anapha se I, Equational division into chromatids appeared to be the most freq uent in univalents of monosomic wheat-rye lines with substitution at t he rye chromosome 5R. The wheat chromosome 5A had an inhibiting effect . The frequency of equational divisions of univalents increased when t he dosage of this chromosome decreased. Thus, it was determined that c hromosomes of the fifth homoeologous group of wheat and rye contain th e Edu genes (Equational division of univalents), which control this pr ocess. The promoter of equational division of univalents, P(Edu), was located on the rye chromosome 5R and the inhibitor I(Edu), was located on the wheat chromosome 5A. A correlation was found between the frequ ency of equational division of univalents in anaphase I and their ''no nincorporation'' into newly formed nuclei in telophase II. Chromosomes that divided into chromatids during anaphase m I were retained at the cell equator in anaphase II and then remained in the cytoplasm. There fore, the higher the frequency of equational division of a univalent i n anaphase I, the less the frequency of its transition through gametes .