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Genome Relations Among Elymus canadensis, Elymus triticoides, Elymus dasystachys, and Agropyron smithii
Douglas R. Dewey
American Journal of Botany
Vol. 57, No. 7 (Aug., 1970), pp. 861-866
Published by: Botanical Society of America, Inc.
Stable URL: http://www.jstor.org/stable/2441345
Page Count: 6
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Hand-emasculated Elymus canadensis pollinated by E~. triticoides, E. dasystachys, and Agropyron smithii yielded 15, 21, and 1 viable hybrid seeds from 56, 52, and 52 florets, respectively. The 28-chromosome species-E. canadensis, E. tritcoides, and E. dasystachys-behaved meiotically as allotetraploids and consistently formed 14 bivalents at metaphase I. Octoploid A. smithii, 2n = 56, averaged 0.41I, 27.72II, and 0.03IV in 87 metaphase-I cells. Agropyron smithii is apparently an allooctoploid or a segmental autoallooctoploid. Meiosis was similar in the E. canadensis x E. triticoides and E. dasystachys hybrids. Chromosome pairing was very low in both hybrids, about two loosely connected open-ended bivalents per cell, and may not represent genuine homologies. The genomes of E. canadensis are distinctly different from those of E. triticoides and E. dasystachys. The E. canadensis x A. smithii hybrid averaged 13.37I and 14.31II in 76 metaphase-I cells. More than half of the bivalents were closed at both ends. Inability to distinguish between auto-and allosyndesis resulted in two interpretations of genome relations. Either A. smithii is an alloploid with two of its four genomes similar to those of E. canadensis, or it is a segmental autoalloploid genomically unrelated to E. canadensis. The first interpretation is favored. Agropyron dasystachyum, or one of its close relatives, and E. triticoides are suggested as possible parents of A. smithii.
American Journal of Botany © 1970 Botanical Society of America, Inc.