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THE ORIGIN OF AGROPYRON SMITHII
Author(s) -
Dewey Douglas R.
Publication year - 1975
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1975.tb14079.x
Subject(s) - biology , agropyron , chromosome pairing , genome , hybrid , elymus , chromosome , genetics , botany , metaphase , pairing , ploidy , meiosis , gene , poaceae , superconductivity , physics , quantum mechanics
The hypothesis that North American octoploid Agropyron smithii Rydb., 2n = 56, originated by hybridization between tetraploid Agropyron and Elymus species, followed by chromosome doubling, was tested by observing chromosome pairing in hybrids of A. smithii with an induced amphiploid, 2n = 56, derived from E. canadensis L., 2n = 28, X E. dasystachys Trin., 2n = 28, F 1 's. Chromosome pairing in A. smithii averaged 0.52 I , 27.70 II , 0.01 III , and 0.01 IV in 184 metaphase‐I cells; and the amphiploid averaged 1.13 I and 27.44 II in 195 cells. Chromosome pairing in A. smithii X amphiploid hybrids averaged 8.20 I , 23.38 II , 0.34 III , and 0.05 IV in 101 metaphase‐I cells. It was concluded that A. smithii was genomically similar to the E. canadensis‐E. dasystachys amphiploid. The basic genome formula of the amphiploid is SSHHJJXX, with the SSHH genomes coming from E. canadensis and the JJXX genomes coming from E. dasystachys. Consideration of the morphological, ecological, and reproductive characteristics of all North American species that contain the basic SSHH and JJXX genomes led to the conclusion that A. dasystachyum (Hook.) Scribn., SSHH, and E. triticoides Buckl., JJXX, are the probable progenitors of A. smithii.