Colchicine induced polyploidy in coriander (Coriandrum sativum L.)

Coriandrum sativum L. (2n=22) is an annual herb that belongs to the family Apiaceae (Umbelliferae) is one of the most important cultivated (spice) crops in the world as well as India. Coriander is an aromatic plant, generally grown in winter. All the parts of the plant are edible but the fresh leaves and the dried seeds are most commonly used in cooking. It is an aromatic herb mainly used as a spice for adding taste and flavor to different food materials. The traditional uses of the coriander plants based on the primary products (fruits and the green herb) are medicinal and culinary (Bhati, 1988). The fruits are considered carminative, diuretic, tonic, stomachic, and antibilious. The essential oils of the fruits are possessing antibacterial and antioxidant activity (Bhandari & Gupta, 1991). Apiaceae is the 16th largest family of flowering plants containing about 200 genera and probably 2900 species; the family is cosmopolitan distributed worldwide except for Antarctica (Bentham, & Hooker, 1883). As per the Angiosperm Phylogeny Group system (APG) IV (2016) the family Apiaceae contains about 434 genera and probably 3,700 species. Polyploidy (having four completes sets of chromosomes) is relatively common in plants. By some estimates, as many as 70% of all angiosperms are natural polyploids (Masterson, 1994). A diploid plant can become polyploid due to disruption in mitosis or meiosis. It can and does occur in nature, but is also induced by using chemicals like colchicine. Colchicine is a chemical, has been used since 1937 in plant breeding work to produce changes in plants by doubling the number of chromosomes in cells, a condition referred to as polyploidy. The increased number of chromosomes usually brings about an increase in the size of the affected cells and various degrees of changes in their functions. A number of reports indicate that besides quantitative changes in plants resulting from polyploidy there also have been changes of qualitative character. These may be in color intensity of leaves and flowers; in fragrance of leaves, flowers, or other plant parts; and in content of oils, starches, sugars, and vitamins. Fundamentally these changes that are ordinarily considered qualitative are mostly, if not entirely, changes of quantitative nature, since they result from either an increase or a decrease of the various products naturally present in the plants. Many workers have worked out the effects of colchicine on different plant species such as; Cosmos sulphureus (Verma et al., 2011b), Chrysanthemum carinatum (Verma et al., 2017), Phlox drummondii (Verma et al., 2018) and Rhoeo discolor (Verma et al., 2011a).