Estimates of the Homoeology of Wheat Chromosomes by Measurements of Differential Affinity at Meiosis
The chromosome complement of the hexaploid wheat of commerce, Triticum aestivum (2n = 6x = 42), can be classified into seven homoeo-logous groups, each of three pairs, or into three genomes, each of seven pairs. The genomes represent the sets of chromosomes combined together—from three distinct diploid species—during the allopolyploid evolution of wheat. The 14-chromosome, diploid, ancestors of T. aestivum were Triticum monococcum, Aegilops speltoides and Aegilops squarrosa, or their close relatives—the contributors of the A, B and D genomes respectively (McFadden and Sears, 1944; Riley, Unrau and Chapman, 1958).
KeywordsWheat Chromosome Marked Chromosome Homoeologous Group Homoeologous Chromosome Chiasma Formation
Unable to display preview. Download preview PDF.
- DARLINGTON, C.D. 1937. Recent Advances in Cytology, 2nd Edition. Churchill, London.Google Scholar
- DOBZHANSKY, T. 1941. Genetics and the Origin of Species, 2nd Edition. Columbia University Press, New York.Google Scholar
- RILEY, R. 1965. The genetic regulation of meiotic behaviour in wheat and its relatives. Proc. 2nd Int. Wheat Genet. Symp. (In the press.)Google Scholar
- RILEY, R., AND CHAPMAN, V. 1964b. The effect of the deficiency of the long arm of chromosome 5B on meiotic pairing in Triticum aestivum. Wheat Inf. Service, 17–18, 12–15.Google Scholar
- RILEY, R., KIMBER, G., AND CHAPMAN, V. 1961. The origin of the genetic control of the diploid-like meiotic behaviour of polyploid wheat. J. Hered.52, 22–26.Google Scholar
- RILEY R. AND LAW C. N. 1965. Genetic variation in chromosome pairing. Adv. Genetics, 13, 57–114.Google Scholar
- RILEY, R., UNRAU, J., AND CHAPMAN, V. 1958. Evidence on the origin of the B genome of wheat. J. Hered., 49, 91–99.Google Scholar
- SEARS, E. R. 1954. The aneuploids of common wheat. Res. Bull. Mo. agric. Exp. Stn. 572.Google Scholar
- SEARS, E. R. 1956. The B genome in wheat. Wheat Inf. Service, 4, 8–10.Google Scholar
- SEARS, E. R. 1966. Nullisomic-tetrasomic combinations in hexaploid wheat. In Chromosome Manipulations and Plant Genetics (ed. R. Riley and K. R. Lewis) a supplement to Heredity, 20, 29–45. Oliver and Boyd, Edinburgh.Google Scholar