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MORPHOLOGY, FERTILITY, AND CYTOLOGY OF AGROPYRON REPENS × AGROPYRON DESERTORUM F 2 'S
Author(s) -
Dewey Douglas R.
Publication year - 1962
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.1537-2197.1962.tb11749.x
Subject(s) - biology , repens , agropyron , backcrossing , hybrid , population , botany , genetics , demography , sociology , gene
D ewey , D ouglas R. (Crops Res. Lab., Agric. Expt. Sta., Logan, Utah.) Morphology, fertility, and cytology of Agropyron repens × Agropyron desertorum F 2 's . Amer. Jour. Bot. 49(1): 78–86. Illus. 1962.—An 82‐plant population derived from F 1 hybrids of A. repens × A. desertorum included morphological types indistinguishable from the parent species as well as many intermediate forms. Most, if not all, of the F 2 population were products of backcrossing of F 1 hybrids to one of the parent species. Backcrossing of F 1 hybrids to A. repens and A. desertorum occurred with equal frequency. Fifty‐four percent of the F 2 plants were completely sterile. Fertility in the F 2 population was related to the nature of the F 1 backcross. F 2 plants obtained from backcrossing to A. desertorum were more fertile than equivalent backcrosses to A. repens. Fertility in the F 2 's was concentrated in a few plants. Nine F 2 's accounted for 85% of the seed produced in the 82‐plant population. The most fertile plant produced 441 viable seeds. Meiotic chromosome counts of 66 F 2 's ranged from 30 to 49 and averaged 36. Chromosome number was related to the direction of the backcross. Chromosome associations in all F 2 plants at metaphase I included many different combinations of univalents, bivalents and trivalents. Occasional pairing of A. repens and A. desertorum chromosomes were noted in some F 2 's. On the basis of morphology, fertility and chromosome pairing, genome formulae were assigned to the parent species. The genome formula of A. repens was given as BBBBCC and A. desertorum was designated as AAAA.