Chromosome Studies and Estimation of Nuclear DNA in Different Varieties of Cuminum cyminum L. and Carum copticum Benth. and Hook

Abstract

The somatic chromosome number in three different varieties of Cuminum cyminum L. and two varieties of Carum copticum Benth. and Hook. are 2n=14 and 2n=18 respectively. Most of the chromosomes in C. cyminum possess submedian or subterminal constrictions. Karyotype analysis shows gross morphological similarity in C. cyminum despite the evolution of different varieties. In length and volume of chromosomes, no marked variations among the varieties are found. The study of DNA content also reveals varietal constancy with slight variation in the different varieties of C. cyminum. A proportionate increase in DNA content is recorded with the increase in length and volume in the varieties.
A gross homogeneity in chromosome morphology is also found in the two varieties of Carum copticum. Majority of the chromosomes possess either nearly median or nearly submedian centromere with little size difference of the chromosome complement. Along with minor karyotype differences in two varieties, a marked variation is found in total chromosome length and volume. However, 4C DNA value between the two varieties of C. copticum reveals a rather consistent picture. Therefore, the differences in chromosome length and volume may be attributed to differential spiralization and condensation of chromosomes along with the content of protein and DNA. The constancy in the amount of DNA in different varieties of same species is a clear index of the selective value of this amount.