Synthetic and natural hybrids of Psathyrostachys huashanica

Three synthetic hybrids and two natural hybrids involving Psathyrostachys huashanica are reported. Gross spike morphology of the hybrids of Pseudoroegneria cognata and Pseudoroegneria spicata ssp. inermis with P. hauashanica was not as indicative of hybridity as in other hybrids involving P. huashanica. Meiotic analyses of these two synthetic hybrids confirmed that little homology exists between the genomes S and Nh. Coenocytism in the hybrids P. huashanica × Secale montanum led to the formation of pseudomicrospores in nondehiscent anthers. No metaphase through telophase chromosome stages could be observed and thus the relationship between genomes Nh and R could not be assessed. Intermediate spike morphology of, and the sterility in, natural hybrids of P. huashanica with P. fragilis and P. juncea substantiated their hybridity. High meiotic pairing in hybrids between P. huashanica and P. fragilis, averaging 1.03 I + 6.48 II, indicated a close relationship between the two species. Occasional high pairing and frequent abnormal meiosis, manifested by degenerating prophase pollen mother cells (PMCs) and empty anthers lacking PMCs of later stages, in the hybrid P. huashanica × P. juncea suggested a more distant relationship between the parental species. It is concluded that P. fragilis is more closely related to P. huashanica than P. juncea.