The Natural Variation in Six Populations of Calendula officinalis L.: A Karyotype Study

In the current investigation, karyotype analysis and chromosome characteristics of six populations of Calendula officinalis L.(pot marigold) from Iran are studied. Results showed that all populations were diploid (2n= 2x= 32), and had symmetrical karyotypes composing mainly of metacentric and submetacentric chromosomes. The mean chromosome length ranged from 1.05 in Karaj to 1.50 μm in Masjed Soleyman 1. Haploid genome length was in the range of 16.89 to 24.07 μm and mean centromeric index (CI) of complements varied from 0.38 to 0.44, indicating the role of the quantitative genomic changes in the diversification of C. officinalis populations. Cluster analysis using chromosomal parameters and based on the UPGMA method classified studied populations into three major groups. In addition, the principal component analysis revealed the first two components account for 99.8% of the total variance. The results of the present study revealed the natural variation in six populations of C. officinalis, which can further serve conservation and breeding planning.