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Synthetic Hybrids of New World and Old World Agropyrons: III. Agropyron Repens X Tetraploid Agropyron spicatum

Douglas R. Dewey
American Journal of Botany
Vol. 54, No. 1 (Jan., 1967), pp. 93-98
Stable URL: http://www.jstor.org/stable/2440890
Page Count: 6
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Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Synthetic Hybrids of New World and Old World Agropyrons: III. Agropyron Repens X Tetraploid Agropyron spicatum
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Abstract

Three hybrids of A. repens, 2n = 42, X A. spicatum, 2n = 28, and two reciprocal hybrids were obtained from emasculated and unemasculated crosses, respectively. The 35-chromosome hybrids tended to be morphologically intermediate between the parent species but resembled A. repens more closely than A. spicatum. A. repens behaved cytologically as a segmental autoallohexaploid, and A. spicatum acted cytologically as an autotetraploid. Mean chromosome associations of 8.04 I, 12.72 II, 0.41 III, 0.06 IV, and 0.009 V were observed in 116 hybrid cells at metaphase I. Most chromosome pairing in the hybrids was attributed to autosyndesis. A. spicatum, A. repens, and their hybrids were represented by genome formulas of SSSS, R1R1X1X1X2X2, and SSR1X1X2, respectively. Hybrid fertility ranged from 0.02 to 0.69 seeds per spikelet.

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