BIOSYSTEMATIC STUDY OF HEXAPLOIDS ELYMUS-TSCHIMGANICUS AND E-GLAUCISSIMUS .2. INTERSPECIFIC HYBRIDIZATION AND GENOMIC RELATIONSHIP

To investigate genomic relationships of Elymus tschimganicus (Drobov) Tzvelev (2n = 6x = 42, S1S2Y genomes) and E. glaucissimus (M. Pop.) Tz velev (2n = 6x = 42, S1S2Y genomes), interspecific hybridizations of t he two target species were carried out with 27 other Elymus species co ntaining the SH, SY, SYH, SYP, SYW, and SH1H2 genomes, respectively, c ollected from different geographic regions. Chromosome pairing behavio r was analyzed at metaphase I in 27 hybrids representing 23 hybrid com binations, and overall genomic relationships of the two target species with the other Elymus taxa were estimated. The study concluded that ( i) interspecific hybridization was principally easy to perform between the Elymus species, but no general pattern of crossability was obtain ed, and all hybrids were completely sterile, (ii) the two species have a similar meiotic pattern in their hybrids with the other Elymus spec ies, and (iii) species containing the SY, SY and and SYH genomes have a generally higher level of genomic homology to the target species tha n those possessing the SH genomes, and the South American hexaploid wi th the SH1H2, genomes has the lowest level of genomic homology to the two target taxa.