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Polyhaploids of Crested Wheatgrass 1
Author(s) -
Dewey Douglas R.
Publication year - 1961
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1961.0011183x000100040006x
Subject(s) - citation , library science , division (mathematics) , agricultural experiment station , crop , agriculture , computer science , biology , agronomy , history , mathematics , arithmetic , archaeology
/"'RESTED wheatgrass exists in natural populations at V> the diploid (2n=l4), tetraploid (2n = 28), and hexaploid (2n = 42) levels. An understanding of the nature of polyploidy in this grass complex is important from taxonomic, phylogenetic, and breeding standpoints. Frequent occurrence of quadrivalent chromosome associations at meiotic metaphase I in tetraploid plants has led some investigators (1, 8) to conclude that tetraploid crested wheatgrass is basically an autotetraploid. Cytological observations upon hexaploid crested wheatgrasses have been very limited because of the relative rarity of hexaploid strains; however, occurrence of hexavalent chromosome associations has been observed by the author and indicates an autoploid origin of hexaploid crested wheatgrass. Knowles (5) reported frequent trivalent associations in crosses of diploid and tetraploid strains and surmised that considerable homology exists between chromosomes of diploid and tetraploid forms of crested wheatgrass. These findings strongly suggest that crested wheatgrass constitutes an autoploid series and as such contains but one basic genome. Polyhaploid plants provide critical information concerning genome homologies in polyploid species. The purpose