Effect of colchicine treatment and polyploidy induction on some morphological, physiological and phytochemical characteristics of Camellia sinensis cv. Kashef

Tea (Camellia sinensis L. O. Kuntze) belongs to the Theaceae family and as one of the most important economic plants in the world, it has many medicinal properties and is consumed as a fun drink. Induction of polyploidy using mutagenic chemicals is one of the methods of breeding medicinal plants in order to increase the ability to produce secondary metabolites. In order to investigate the effect of colchicine treatment on the induction of polyploidy and to compare the changes of different traits in tetraploid and diploid plants (control) of Kashef cultivar, an experiment was carried out as a factorial in the form of a completely randomized design with two factors contains different concentrations of colchicine (0, 0.2, 0.5 and 1%) and duration times (3 and 6 consecutive days) with three replications. Morphological, microscopic and chromosomal counts were used to determine the ploidy level. The number of chromosomes in diploid and tetraploid plants was recorded as 30 (2n=2x=30) and 60 (2n=4x=60), respectively. The results showed that the concentration of 0.5 % colchicine in a period of 6 consecutive days with an efficiency of 12.82 % is the most suitable treatment for the production of tetraploid plants. Induction of polyploidy caused significant changes in the leaf size, chlorophyll and carotenoid contents and increased phytochemical compounds such as polyphenol, caffeine and antioxidant activity in tetraploid shoots compared to diploid. Based on the results of this experiment, increasing the ploidy level caused an increase in antioxidant compounds and some phytochemical compounds in tea medical plant.