Intergeneric Hybrids of Agropyron and Pseudoroegneria

Two intergeneric hybrids, Agropyron cristatum x Pseudoroegneria stipifolia (2n = 14) and A. desertorum x P. stipifolia (2n = 28), were produced by controlled pollination. Spike morphology of the hybrids was intermediate to that of the parents. Size differences between Agropyron (large) and Pseudoroegneria (small) mitotic chromosomes facilitated interpretation of chromosome pairing in the hybrids. Meiotic chromosome pairing in the diploid hybrids, x̄ = 3.09 II, was largely allosyndetic between homoeologous chromosomes of the S and the P genomes. Autosyndetic pairing prevailed in the tetraploid hybrids. Because the Agropyron chromosomes can pair with the Pseudoroegneria chromosomes, gene introgression between species in these two genera is possible.