Character association, path coefficient and genetic diversity analyses of quantitative and qualitative traits in greater yam (Dioscorea alata L.) genotypes from North-western India

Globally, greater yam ( Dioscorea alata L.) is an economically important tuber crop that contributes to food security, household income and rural livelihoods through its production and value-added utilization. However, systematic evaluation of its genetic resources remains limited, particularly under semi-arid North-West Indian conditions. Therefore, the present study aimed to assess 30 greater yam genotypes for genetic variability, trait associations, and genetic diversity to identify suitable genotypes for yield and quality traits. A randomized block design (RBD) experiment comprising three blocks, with all 30 greater yam genotypes represented once in each block, was conducted at Udaipur, India, during three kharif seasons (2018–2020) to evaluate the genotypes. A total of 23 morphological, yield, and biochemical traits were subjected to analyses of variability, correlation, path coefficient, and cluster analyses. Highly significant genotypic differences for all traits indicated the availability of substantial variability for selection. High genotypic and phenotypic coefficients of variation were observed for tuber weight (33.40%, 28.43%) and yield per vine (37.59%, 30.62%), while total soluble solids also showed high variation (24.23%, 24.40%). Vine length exhibited high heritability (84.28%) and genetic advance (95.78%), indicating substantial genetic variability and better potential for selection. Tuber yield per vine showed strong positive correlations with tuber length (0.99), leaf number (0.99), tuber weight (0.97), and vine length (0.96). Path analysis identified vine length (1.033) and tuber length (0.760) as major direct contributors to yield. Tocher’s clustering grouped genotypes into four clusters, with maximum divergence between Clusters III and II (400.62), while Cluster II showed superior yield and quality traits. Genotypes TGy-14-9, MPY-8, and MPY-4 were identified as suitable for high yield, starch, and ascorbic acid content, respectively. The results provide a strong basis for selection and hybridization programs in greater yam improvement. Vine length and tuber length should be prioritized as selection indices, and the identified promising genotypes can serve as valuable genetic resources for breeding high-yielding, nutritionally-enhanced varieties suitable for semi-arid regions.