A STUDY ON CORRELATION AND ASSOCIATION OF CHARACTERS OF EXACUM TETRAGONUM ROXB. IN NORTH KERALA, INDIA

Western Ghats provide asylum to several endemic plants. Exacum tetragonum Roxb. is one of the important endemic herbs inhabiting the hilly tracts and midlands of Kerala, the state of India located towards the south-western side of the Western Ghats. The plant is used for treating fever, stomach disorders, gout, diabetics, and eye diseases. It is also found associated with antioxidant, anti-inflammatory, anti-helminthic and anti-hyperglycemic activities. Correlation and association of characters of this important medicinal plant was analyzed based on the observations on thirteen salient morphological characters recorded from twenty three populations of the species distributed across Malappuram, Thrissur, Kozhikode and Palakkad Districts of Kerala State of India. All the characters studied such as plant height, number of leaves, number of flowers, number of inflorescences, leaf length, leaf breadth, peduncle length, pedicel length, internodal length, leaf area, mean stem girth, number of branches and fresh weight of plants showed statistically significant variations between the populations. Number of flowers showed significant positive correlation with the maximum number of characters (ten characters) whereas number of leaves showed significant positive correlation with the minimum number of characters (two characters). By factor analysis, two factors could be extracted and fresh weight of plant was found to be the lead character. Significant variability with regard to morphological characters indicates the strong genetic base of the plant species in the field. However, drastic changes in its habitat for various reasons can certainly cause severe threats to its continued existence and hence appropriate actions to conserve the natural habitats of this species are vital.