Genetic variability and evolutionary relationships between Amaranthus spp. as revealed by karyotype analysis

Author(s): Reda Helmy Sammour, Safaa Radwan, Mohammed Mira, Salwa Badar

This work aimed at identifing genetic variability and assesing the evolutionary relationships between 24 accessions of eight Amaranthus species, based on the morphological features of the basic chromosome numbers and numerical characterization of the karyotypes using total chromosome length (TCL), mean chromosome length (MCL) and mean centromeric index (MCI). The basic chromosome numbers were analyzed cytologically by Feulgen staining. They were 16 for all the studied accessions, except some accessions belong to A. powellii and A. palmeria which exhibited n=17. The karyotypes of the studied accessions had a predominance of metacentric chromosomes with some accessions characterized by subtelocentric chromosomes. The karyptype analysis showed a variation in the karyotype of the accessions of the same species. The variation may be considered of adaptive significance. Cluster analysis showed A. hybridus and A. powelli as a progenitor ofAmaranthus species. The obtained data indicated that A. powelli could be considered the most advanced species, since it has the smallest chromosome length.

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