Hybrids and Induced Amphiploids Involving Agropyron curvifolium, A. repens, and A. desertorum
- Douglas R. Dewey
Agropyron curvifolium Lange (2n=28) was hybridized with Agropyron repens (L.) Beauv. (2n=42). An amphiploid (2n=70) was produced by treatment of an F1 (2n=35) with colchicine. The purposes of this study were to determine the mode of pollination and nature of polyploidy in A. curvifolium; to describe the morphology, cytology, and fertility of F1 hybrids and a C0 amphiploid of A. repens × A. curvifolium; and to describe a threespecies amphiploid hybrid involving A. repens, A. curvifolium, and A. desertorum (Fisch. ex Link) Schult.
Most A. curvifolium plants were highly self-sterile. Occasional quadrivalents in all A. curvifolium plants at metaphase I indicated that they were partial autoploids whose genome formula could be written as E1E1E2E2. Chromosome pairing in the F1 hybrids averaged 14.82I, 9.73II, 0.20III, and 0.03IV. Most, if not all, pairing was the consequence of autosyndesis. The genome formula of the F3 was designated as E1E2S1S2X.
Chromosome doubling of the F2 hybrid increased plant height 20 to 25 cm. The amphiploid was meiotically irregular, averaging 6.02 univalents at metaphase I, 1.43 laggards at anaphase I, and 2.01 micronuclei per quartet. In spite of meiotic Irregularity, the amphiploid produced 90% stainable pollen. Some C1 progeny were the result of crossing of the A. repens-A. curvifolium C0 amphiploid (2n=70) to an A. repens-A. desertorum C0 amphiploid (2n=70). The three-species amphiploid hybrids averaged 71% stainable pollen. The three-species amphiploid hybrids were the most vigorous plants in the study and they may warrant the attention of grass breeders.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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