Morphometric, chemotypic, and molecular diversity studies in Andrographis paniculata

ABSTRACT Genetic diversity based on molecular, morphological, and chemical characteristics was examined in Kalmegh (Andrographis paniculata). The study evaluated 10 Kalmegh accessions in a randomized complete blocks design and characterized over two Kharif seasons (2017–18 and 2018–19) for plant characteristics, yield, and andrographolide, neoandrographolide, and 14-deoxy-11, 12 dehydroandrographolide (14-DDA). Analysis of variance revealed differences among all the characters. Morphological diversity studies based on genetic similarity matrix and principal component analysis formed three clusters, cluster-I (two), cluster-II (three), and cluster-III (five) accessions. Molecular diversity analysis was performed by using arbitrary amplified 20 intersimple sequence repeat (ISSR) primers, generated 202 amplified products with an average of 10.1 amplicon per primer, among them 140 (7.00) were polymorphic and 62 (3.10) were monomorphic bands. Polymorphic information content for ISSR primers ranged from 0.02 to 0.37 and resolving power ranged from 0.20 to 9.02. Clustering based on unweighted pair group method with arithmetic mean grouped 10 germplasms into two broad clusters and two subclusters in cluster one. Chemical analysis of accessions revealed considerable variability among the 10 accessions. Andrographolide, neoandrographolide, and 14-DDA content ranged from 2.29% (IC-342195) to 3.59% (IC-342134), 0.58% (Anamalai), to1.86% (IC-471917) and 0.06% (Sirsi) to 0.12% (Anamalai), respectively. There was a negative correlation between morphological and ISSR markers.