The chromosome number, 2n = 36, of the Himalayan forage grass Pennisetum flaccidum Griseb. was reported for the first time. Chromosomes formed 12 to 14 bivalents and two to three quadrivalents at diakinesis. The species was considered to be tetraploid with x = 9 as the basic number. Meiosis was generally regular with some early disjunction, laggards, and micronuclei. Pollen sterility was 22.8%. Embryo development was aposporous. Normal megaspores degenerated following formation of several four‐nucleate nucellar sacs. Ultimately, one nucellar embryo sac survived and gave rise to a single embryo. Endosperm development and division was presumed to stimulate embryo differentiation and development.
Five accessions of Pennisetum orientate Rich were tetraploid with 2N = 36. Pairing at diakinesis and metaphase I was generally normal, as was anaphase I disjunction. Quadrivalent frequency per cell ranged from zero to eight, but was usually three to five. Pollen sterility was about 28% and due, in part, to laggards, rare unequal disjunction, and univalent misdivision. Embryo development was aposporous. Development of nucellar embryo sacs was accompanied by degeneration of sexual tissue. multiple embryos were not found.
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