Insight into the morphological and bioactive variability in the ex-situ genepool of Gymnema sylvestre accessions collected from Peninsular India

Gymnema sylvestre (Retz.) R.Br. ex Sm. (Gudmar) is a medicinal crop that is highly valued because of its antidiabetic and diverse therapeutic properties. In this study, 35 accessions of G. sylvestre collected from different regions of Peninsular India (Karnataka, Tamil Nadu, Kerala, Telangana, and Andhra Pradesh) were characterized in terms of morphological traits and the active biocomponent gymnemagenin. Morphological characterization for five qualitative and 11 quantitative traits indicated the existence of significant variability between the accessions. Pearson’s correlation showed that the leaf size and yield exhibited significant negative correlations with the gymnemagenin content. Thus, small-leaved accessions with a low leaf yield exhibited a higher bioactive content and vice versa. Principal component analysis for 11 quantitative traits revealed that fresh leaf yield per plant, dry leaf yield per plant, gymnemagenin percentage, leaf area, leaf area index and chlorophyll content contributed maximum to the variability. Dendrogram based on Tocher method grouped the 35 accessions of G. sylvestre into six major clusters mostly according to the leaf traits and irrespective of the area of collection. The intracluster distance (34.85) was the highest for Cluster 3, which indicated the presence of highly diverse genotypes within it, and the highest intercluster distance was observed between Cluster 2 and Cluster 6 (688.04). Few promising genotypes viz., IIHR-GS-27 and IIHR-GS-9 were identified for highest fresh leaf yield per plant with 1.76 kg and 1.74 kg leaves/plant, respectively, and IIHR-GS-44 for high gymnemagenin content (1.95%) followed by IIHR-GS-37 (1.72%). Promising morphotypes and chemotypes identified in the diverse genepool can be further deployed in crop improvement programmes to promote the cultivation and commercialization of this species.