Chromosome counts and karyotype features of different ecotypes of Allium L. species (Amaryllidaceae – Subg. Melanocrommyum) in Iran

Abstract

This study aimed to investigate the karyotypes of five Allium species, which belong to three sections of the subgenus Melanocrommyum. Bulbs from these species were collected from natural habitats in Iran, and their somatic chromosomes were analysed. The results revealed that all examined members of subg. Melanocrommyum had a basic chromosome number of x=8 and were diploid (2n=2x=16). Chromosomal data for A. saralicum and A. shatakiense are reported here for the first time. The karyotypes exhibited a variety of chromosome types and sizes, including variations observed among different accessions of the same species. In particular, A. saralicum showed satellite chromosomes ranging in size from 2.2 to 3.71 µm, located on the short arm. Seven accessions of A. saralicum, A. stipitatum, and A. haemanthoides demonstrated the presence of 1-3 B chromosomes with centromeres located in the median or subterminal position. Notably, the number of B chromosomes varied even among different accessions of the same species. Based on various indices, the karyotypes of the species were classified into symmetric and asymmetric groups. All karyotype asymmetry methods consistently identified A. stipitatum as the species with the most asymmetric chromosomes, while A. ubipetrense was recognized as the most symmetric species. This study contributes to the karyological knowledge of the genus Allium and provides valuable data for future taxonomic research. It emphasizes the significance of chromosomal characteristics in understanding plant evolution and species diversity within the Allium genus.