CYTOLOGY OF INTERGENERIC HYBRIDS BETWEEN PSATHYROSTACHYS AND ELYMUS WITH AGROPYRON (POACEAE, TRITICEAE)

This paper describes the cytogenetics and fertility of intergeneric hybrids of Psathyrostachys stoloniformis x Agropyron cristatum and two Elymus species, E. dentatus ssp. ugamicus and E. grandiglumis x A. cristatum. Bivalent frequencies of metaphase I cells in the F1 hybrid P. stoloniformis (NN) x Agropyron cristatum (PP) ranged from 0 to 4 per cell, with an average of 0.87 bivalent per cell and a c value of 0.07. The hybrid E. dentatus ssp. ugamicus (SSYY) x A. cristatum (PP) averaged 3.07 bivalents per cell and ranged from 0 to 7 with a c-value of 0.27. Bivalents were predominantly end to end associations. Meiotic analysis in E. grandiglumis (SSYYPP) x A. cristatum (PP) revealed an average of 6.84 bivalents per metaphase I cell with a c value of 0.73. This hybrid had a chromosome number of 2n = 30 rather than the expected 2n = 28. All hybrids had less than 1 % stainable pollen and set no seed under open-pollination.