Karyomorphology, ploidy analysis, and flow cytometric genome size estimation of Medicago monantha populations

Abstract

Karayomorphological analysis and monoploid genome size (2Cx DNA) of 12 Iranian Medicago monantha populations are reported. Flow cytometric analysis were conducted on freshly collected seeds, using Solanum lycopersicum cv. Stupicke (2C DNA = 1.96 pg), as the internal reference standard. All populations were diploid with variable degrees of mixoploidy and two different chromosome numbers within each population. Totally, six chromosome numbers of 22, 28, 30, 32, 36, and 40 were identified. Two-typed chromosomes ("m”, “sm”) with a mean length of 1.65 µm (0.98-2.99 μm) formed seven different karyotype formulas. Karyotypes were mostly symmetrical, implying the evolutionary effect of natural and unnatural selection. The UPGMA phenogram categorized the populations into four major clusters. The mean 2Cx DNA value of all assessed populations was 4.10 pg (2.88–4.56 pg). Using the matrix of karyotype similarities, cluster analysis was carried out and the dendrogram classified the populations into four major clusters. Our results can be employed in the taxonomic and phylogenetic consideration of the genus and toward improved breeding programs.