مطالعه سيتوژنتيكي در دو گونه نعنا (Mentha longifolia, Mentha spicata)

Study of cytogenetic in Mentha spicata and M. longifolia

Several cytogenetic investigation suggested that Mentha is a group of polyploids, with different chromosome numbers reported for each of the several species. This may cause the taxonomic confusion among the species. This study was carried out to evaluate the cytogenetic properties of 12 genotypes belonging to M. longifolia and M. spicata, collected from central regions of Iran. Several cytogenetic characteristics such as number of chromosomes, average of chromosome length and width, the largest and smallest chromosome length and width and total chromosome length and width were recorded for each of genotype. Results showed the number of chromosome in three genotype of M. longifolia were 24. Also result of chromosome numbering showed that genotypes number 1, 4 and 8 of M. spicata were diploid and genotypes number of 2, 3, 7 and 12 were triploid and genotypes number of 9 and 10 were tetraploid. Nine genotype of M. spicata representing three cytotypes including diploid, triploid, and tetraploid. Among the three genotype of M. longifolia, average length of chromosome ranged from 0.56 micron in genotype six to 0.93 micron in genotype number five. Among nine genotype of M. spicata, average length of chromosomes ranged from 0.52 micron in genotype number two to 0.88 in 8 genotype.