Genetic divergence in Coleus forskohlii Briq.

Coleus forskohlii Briq. is an important medicinal plant indigenous to India. Genetic divergence among 37 genotypes collected from different places of Tamil Nadu (18) and Karnataka (19) was quantified for the 13 morpho-economic traits viz., plant height, foliage weight, number of leaves, number of branches, stem girth, petiole length, root/tuber girth, root/tuber length, number of roots/tubers, total dry matter production, harvest index, leaf area index and root/tuber yield. Based on their values, all the 37 genotypes were grouped into three clusters such that the genotypes within a cluster had smaller D(2) values among themselves than those belonging to different clusters. Tuber/root yield contributed maximum towards total divergence. Leaf area index, harvest, index and total dry matter production were the other important contributors for total divergence. The inter-cluster D(2) values varied from 48128.684 (between clusters I and II) to 334563.156 (between clusters II and III) and the intra-cluster values varied from 3116.698 (cluster I) to 99778.281 (cluster II).