Hybrids Between Agropyron desertorum and Induced-Tetraploid Agropyron cristatum1
- Douglas R. Dewey and
- P. C. Pendse2
Cross-compatibility of Agropyron desertorum (Fisch. ex Link) Schult. and induced-tetraploid A. cristatum (L.) Gaertn. was variable, and seed set ranged from 0 to 20 hybrid seeds per spike. Many hybrids were exceptionally large and leafy and compared favorably with the most vigorous crested wheatgrasses. The A. desertorum, 2n=31, and induced-tetraploid A. cristatum, 2n=28, parents behaved cytologically as autoploids. The three extra A. desertorum chromosomes were believed to be supernumeraries. Chromosomes numbers of 42 hybrids ranged from 2n=28 to 2n=32. Chromosome associations in 28-chromosome hybrids averaged 0.02 I, 8.54 II, 0.02 III, 2.25 IV, 0.22 VI, and 0.06 VIII in 180 cells at diakinesis. Hexavalent and octavalent associations at diakinesis and bridge-fragment formations at anaphase I and II signified structural heterozygosity between A. cristatum and A. desertorum genomes. Seed set ranged trom 0.02 to 2.30 seeds per spikelet in 39 unselected hybrids and from 1.71 to 4.15 seeds per spikelet in 15 selected hybrids. The prospects of utilizing A. desertorum ✕ induced-tetraploid A. cristatum hybrids in a breeding program appear favorable in spite of some parental cross-incompatibility and reduced fertility of some hybrids. Taxonomic implications of the data are discussed.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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