Karyotype analysis and genome relationships of 22 diploid species in the tribe Triticeae

TLDR

Morphologically unique genomes aid genome identification and complement chromosome pairing interpretation in Triticeae. The authors analyzed karyotypes of 24 diploid Triticeae taxa across eight genera using traditional preparations and an interactive microcomputer program that generated idiograms arranging chromosomes by length. The genomes are ordered by decreasing length as R, I, P, N, J, S, H, W, and karyotypes within a genus consistently display a unique pattern, making morphologically distinct genomes useful for genome identification.

Abstract

Karyotypes were analyzed on 24 diploid taxa (mostly perennials) belonging to eight Triticeae genera, which are defined by genome content (basic set of seven chromosomes): (i) Agropyron (P genome), (ii) Thinopyrum (J genome), (iii) Secale (R genome), (iv) Hordeum (i genome), (v) Pseudoroegneria (S genome), (vi) Psathyrostachys (N genome), (vii) Australopyrum (W genome), and (viii) Critesion (H genome). In addition to traditional karyotype preparations, the metaphase root-tip chromosomes were analyzed by an interactive microcomputer program that printed an idiogram in which chromosomes were arranged by length. Genomes, arranged by decreasing length, are R, I, P, N, J, S, H, and W (with lengths ranging from 61.29 to 39.39 μm). Almost without exception, karyotypes of species within a genus manifest a pattern that is unique to the genome. Morphologically unique genomes are useful diagnostic features in genome identification and can complement interpretation of chromosome pairing in genome analysis.Key words: Triticeae, diploid, karyotype, genome relationship.