MORPHOLOGY AND CYTOLOGY OF INTERGENERIC HYBRIDS INVOLVING LEYMUS-MULTICAULIS (POACEAE)

The morphology and meiotic behaviour of pollen mother cells were studied in hybrids involving Leymus multicaulis (2n = 28) x Psathyrostachys osrachys huashanica (2n = 14), L. multicaulis x P. juncea (2n = 14), and L. secalinus (2n = 28) x L. multicaulis. Chromosome pairing was almost identical in the L. multicaulis x P. huashanica, and L. multicaulis x P. juncea hybrids, in which it averaged 7.30 univalents + 6.69 bivalents + 0.096 trivalents and 7.48 univalents + 6.75 bivalents, respectively. The meiotic pairing in the two hybrids indicated that one L. multicaulis genome was closely homologous with the P. huashanica and P. juncea genomes. Both P. huashanica and P. juncea are possibly donors of one L. multicaulis genome. Chromosome pairing in the L. secalinus x L. multicaulis hybrid averaged 4.49 univalents + 11.71 bivalents + 0.02 trivalents, indicating that the genomes of L. multicaulis and L. secalinus are to some degree homologous. However, they are sufficiently differentiated to insure species distinctness.