HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Dewey, D. R. Search for Related Content PubMed Articles by Dewey, D. R. Agricola Articles by Dewey, D. R.

Reproduction in Crested Wheatgrass Pentaploids¹

Pentaploid, 2n=35, crested wheatgrasses [Agropyron cristatum (L.) Gaertn.] and related taxa., were derived by crossing natural and induced tetraploids, 2n=28, with hexaploids, 2n=42. The pentaploids backcrossed readily to tetraploids and hexaploids, but they crossed only rarely with diploids, 2n=14. Chromosome numbers in 5x-2x, 5x-4x, 5x-5x, and 5x-6x hybrids ranged from 2n=21 to 25, 2n=28 to 35, 2n=28 to 42, and 2n=35 to 60, respectively. Three hyperoctoploid hybrids—2n=58, 59, and 60—from 5x-6x crosses probably resulted from union of unreduced male gametes, n=42, and reduced eggs, n=16 to 18. The pentaploids produced functional reduced gametes with n=14 to 21 chromosomes, and the gametic chromosome numbers were distributed somewhat normally, with a mean between n=17 and 18. High multivalent associations at metaphase-I in some hybrids were caused by a combination of autoploidy and structural heterozygosity. Fully fertile tetraploid and hexaploid hybrids were recovered immediately from 5x-4x and 5x-6x crosses, respectively. Grass breeders should not find it difficult to transfer genes, chromosomes, or even whole genomes between tetraploid and hexaploid crested wheatgrasses. Genetic transfer between diploid and polyploid races is somewhat more difficult.

Key Words: Agropyron cristatum • Autopolyploidy • Genome analysis • Grass breeding

² Research Geneticist, ARS, USDA, Logan, UT 84322.

This article has been cited by other articles:

				K. B. Jensen, S. R. Larson, B. L. Waldron, and K. H. Asay Cytogenetic and Molecular Characterization of Hybrids between 6x, 4x, and 2x Ploidy Levels in Crested Wheatgrass Crop Sci., December 2, 2005; 46(1): 105 - 112. [Abstract] [Full Text] [PDF]