Class-based stratification matrix for physical leaf traits in phenetic relations of Withania somnifera (L.) Dunal accessions

Withania somnifera (L.) Dunal is a promising herb with many pharmaceutical and therapeutic uses ranging from immunomodulation to anticarcinogenicity. It is commonly known as Indian ginseng, as it is comparable to Panax ginseng, which is a widely studied and utilized herb. There are limited studies on the genetic diversity of W. somnifera from the northeastern region of the Indian Subcontinent. This paper describes the characterization of wild accessions collected from Tamil Nadu State. A total of 15 accessions collected from wild populations were studied for their physical leaf traits such as leaf fresh weight (g), dry weight (mg), leaf dry matter content (mg g−1), specific leaf area (mm2 mg−1), leaf size (mm2), total carbon and nitrogen, and total withaferin-A content in leaves. An attempt was made to correlate physical leaf traits with withaferin-A content. The molecular traits, which were treated in a presence–absence matrix, failed to group the hyper-withaferin-A accessions. The quantified physical leaf traits were converted into a presence–absence matrix using a novel method of class-based stratification. The phenetic relations inferred from the Fitch–Margoliash algorithm applied to physical leaf trait data resulted in grouping of accessions with high withaferin-A content. These traits were used in the selection of promising accessions which can be further used for breeding programmes.