Multivariate analysis of seed chemical diversity among wild fenugreek (Trigonella monantha C. A. Mey.) ecotypes

Wild fenugreek (Trigonella monantha), a multi-purpose annual plant, has traditionally been used as a food, forage, and medicinal plant. However, the knowledge of the diversity of its chemical characteristics is limited. In this study, 40 wild fenugreek ecotypes collected from their natural habitats in Iran and grown together in field conditions, were analyzed for their seed chemical properties.

The ecotypes were cultivated in a randomized complete block design (RCBD) with three replications. The results of ANOVA revealed a significant difference among the ecotypes for all measured characters (P < 0.01). The results showed a high level of diversity among the ecotypes based on the measured characters, including antioxidant activity (48.19 to 86.85%), phenol (0.82 to 1.51 mg gallic acid per g dry weight), flavonoid (1.07 to 3.11 mg quercetin per g dry weight), trigonelline (0.02 to 0.08 mmol/l), 4-hydroxyisoleucine (0.197 to 0.906 mg/g), sucrose (0.13 to 3.77 mM), glucose (1.07 to 12.1 mM), and fructose (13.3 to 45.5 mM). The cluster analysis divided the ecotypes into four groups and the PCA analysis showed that the three first components explained 73% of the total variance among the ecotypes. Also, heat map correlation revealed that many positive and negative correlations were observed among the measured characters. The results did not show a relationship between the amounts of compounds and the place of sample collection.

The present study suggests considerable diversity in the seed chemical compositions of the wild fenugreek ecotypes. Therefore, many ecotypes could be useful for medicinal purposes, as well as for human nutrition.