CYTOLOGICAL STUDIES OF F1 HYBRIDS AND A DIHAPLOID FROM THE INTERSPECIFIC CROSS ELYMUS-ANTHOSACHNOIDES X E-ABOLINII (TRITICEAE, POACEAE)

Interspecific hybrids (2n = 4x = 28) and a dihaploid (2n = 2x = 14) of Elymus anthosachnoides (Keng) Love (2n = 4x = 28) were obtained from crosses between E. anthosachnoides (female) and E. abolinii (Drob.) Tzvelev (male) (2n = 4x = 28, SSYY). The dihaploid had probably resulted from selective elimination of the male parental chromosomes during early embryo development. Electrophoretic patterns of two isozyme systems and meiotic chromosome behaviour were investigated in the two parental species, their hybrids, and the dihaploid. Elymus anthosachnoides and E. abolinii had predominant ring bivalent formation with chiasmata averaging more than 26 per cell at metaphase-I. The hybrids had reduced chiasma formation averaging less than 16 per cell, whereas the dihaploid formed very low chromosome pairing with an average of 0.31 chiasmata per cell. Chromatid bridges accompanied by small fragments were observed at anaphase-I of the hybrids and dihaploid. This study reveals that (i) Elymus anthosachnoides is a strict allotetraploid in nature; (ii) it contains the same, but modified, genomes, i.e., the ''SY'' genomes as E. abolinii; and (iii) a low homoeologous affinity exists between the ''S'' and ''Y'' genomes of E. anthosachnoides.