CYTOGENETIC AND GENOMIC RELATIONSHIPS OF THINOPYRUM-ELONGATUM WITH 2 PSATHYROSTACHYS SPECIES AND WITH LEYMUS-SECALINUS (POACEAE)

Intergeneric hybridizations were made between T. elongatum, and two Ps athyrostachys and five Leymus species. The seed set obtained on T. elo ngatum X Leymus hybrids ranged from 5.65% to 20.00%, depending on Leym us species. The seed set obtained on T. elongatum x Psathyrostachys hy brids ranged from 16.07% to 19.70%. Meiotic pairing at metaphase-I in JN diploid hybrids of T. elongatum X Psathyrostachys species revealed a very low level homology between the basic J and N genomes, and furth er demonstrated that the two genomes are quite diverged. Chromosome pa iring in the T. elongatum X Leymus secalinus hybrid averaged 15.19 uni valents + 2.62 rod bivalents + 0.26 ring bivalents + 0.02 trivalents, suggesting that the partial J(e) chromosomes of T. elongatum has homol ogy with Leymus secalinus genomes. L. secalinus might have 3-4 chromos omes originating from J(e) genome.