THE GENOME STRUCTURE OF THE 2 FORMS OF TH E INCOMPLETE WHEAT AGROPYRON-INTERMEDIUM AMPHIPLOIDS (2N=56)

Two forms of incomplete wheat- Agropyron intermedium amphiploids (IWAA , 2n = 56) were studied by the C-method of differential staining of ch romosomes. The karyotypes of the studied forms were represented by the complete chromosome set of A, B, and D genomes of Triticum aestivum ( 2n = 42), and by varying number of chromosomes of Agropyron intermediu m. IWAA153 contains seven chromosome pairs of A. intermedium, IWAA139 contains six pairs and the pair with the C-banding pattern markedly di fferent from chromosomes of A. intermedium and wheat. C-banded chromos omes of wheat practically did not exhibit any polymorphism in any of I WAA karyotypes. At the same time, C-banding pattern of four chromosome s of genome A (I A, 4A, 5A, 6A) was different in IWAA153 and IWAA139. Comparative analysis of A. intermedium subgenomes, which were included in karyotypes of IWAA153 and IWAA139, demonstrated that three chromos omes had a uniform C-banding pattern, while the other four had a marke dly different pattern of heterochromatin (HC) distribution. The study of the chromosome conjugation at MI of meiosis was performed on IWAA 1 39, IWAA153, F1 of this couple, and on the two wheat varieties ''Miron ovskaya 808'' and ''Kavkaz''. The number of univalents in IWAA was hig her than in the wheat varieties. In F1 of IWAA153 x IWAA139 hybrid nor mally conjugating chromosomes were accompanied by univalents and multi valents.