Abstract
Chromosome numbers in 140 accessions of 37 annual and perennial species of Trifolium L. in Iran were counted and studied here. The chromosome number of 2n=16 was documented in Trifolium radicasum in Iran. New cytotypes were found in Trifolium ambigum, T. fragiferum, T. montanum, T. nigrescens, T. stellatum and T. tumens. This study deposited more data in chromosome numbers of Trifolium to determine the genus has high diversity of ploid level. Their karotypic formula showed that the most of the chromosomes were median-, submedian- or terminal-centromeric. The smallest chromosomes were found in Sections Versicaria and Mistyllus, while the largest chromosomes were found in Sections Trifolium and Tricocephalum. Thus, Trifolium seemed to be heterogeneous with respect to morphological characters of chromosomes.
