Cytogenetic evolution in the Triticinae: homoeologous relationships

Abstract

The subtribe Triticinae consists of five genera, namely Aegilops, Agropyron, Haynaldia, Secale and Triticum, all with x=7 as the basic number and possibly derived from a common ancestor (PP). The homoeologous relationships known to exist between individual chromosomes from different genomes of hexaploid wheat, are being extended to other members of the subtribe. The available work in the area of homoeologous relationships in the subtribe Triticinae has been reviewed in detail. Homoeologous relationships of one chromosome of each of the four species of Aegilops i.e. Ae. comosa, Ae. caudata, Ae. umbellulata and Ae. bicornis are now known. Similarly, in the genus Agrophyron, relationships of six chromosomes of A. clongatum (2n=70), two chromosomes of A. clongatum (2n=14) and of two chromosomes of A. intermedium are known. The genus Secale, for which the author's own work is also available, has been most extensively studied and relationships of at least five chromosomes of S. cereale are now known. No other species of Secale has been used in similar studies. In the genus Haynaldia, no chromosome could be shown to have any relationship with a wheat chromosome, perhaps due to low erossability with Triticum aestivum. The above work has been discussed and reviewed.