Assessment of variability in secondary metabolites and expected response to genotype selection in fenugreek (Trigonella spp.)

Abstract A better understanding of metabolites assists breeding industrial-friendly medicinal plants. The main objectives of the present study were to compare and screen several fenugreek accessions and estimate genetic variability with respect to phenolic and non-pheneolic metabolites. The leaf extracts of accessions in field experiment being established in two growing seasons (2014-15, 2015-16) were subjected to high- performance liquid chromatography (HPLC). No one accession was found to have high levels of all metabolite compounds but several accessions accumulated more than one metabolite at high level. T.f.g[H-37527] had the highest catechin (65.33 mg L −1 ) and rutin (26.46 mg L −1 ) whereas p-coumaric acid was not identified in several accessions. Catechin (36%), trans-ferulic acid (15%) and hesperetin (13%) with the highest share in the total metabolite content were the predominant compounds identified. Coumarin with the highest genotypic variation (GCV = 128.05%) was identified at 280 nm, whereas hesperetin which was identified at the same wavelength had the lowest GCV (39.97%). All metabolites were identified at 280 nm wavelength except chlorogenic acid which was identified at 320 nm. Estimation of response to selection (RS) showed that catechin (RS = 35.87%) was more responsive to selection whereas quercetin (RS = 3.82%) was relatively less responsive. Assessment of interrelationships between metabolites demonstrated the strong association of catechin, trans-ferulic acid and rutin accumulation in accessions tested. Overall, knowledge of genetic variation identified for metabolites tested significantly contributes to designing intra-specific crosses with potential interest to metabolite breeding programs and creates a solid basis for genotype selection aimed at better food quality, higher pharmaceutical uses and further improvement of fenugreek.