Trait Association and Path Coefficient Analysis for Green Fodder Yield and Nutritional Traits in Fodder Cowpea [Vigna unguiculata (L.) Walp.] Germplasm

Abstract

Improving green fodder yield in cowpea requires a clear understanding of the relationships among yield-contributing traits and the magnitude of their effects on productivity. The present study investigated trait associations and the direct and indirect effects of important agro-morphological and quality traits on green fodder yield in fodder cowpea [Vigna unguiculata (L.) Walp.]. A total of 104 genotypes, comprising 100 germplasm accessions and four check varieties, were evaluated during Kharif 2022 at the Agricultural Research Institute, Rajendranagar, Hyderabad, Telangana, using an Augmented Complete Block Design. Observations were recorded for fourteen yield and quality attributes. Phenotypic correlation analysis revealed that green fodder yield had significant positive associations with plant height (0.24), leaf length (0.26), fresh leaf weight (0.29), fresh stem weight (0.92), dry fodder yield (0.31), dry matter content (0.25), and crude protein content (0.20), whereas the leaf-to-stem ratio exhibited a significant negative association with green fodder yield. Path coefficient analysis indicated that fresh stem weight exerted the highest positive direct effect (0.8919) on green fodder yield, followed by dry matter content (0.0569), dry fodder yield (0.0532), number of primary branches per plant (0.0315), leaf length (0.0161), number of secondary branches per plant (0.0094), and fresh leaf weight (0.0027). The coefficient of determination (R² = 0.8831) indicated that the included traits explained 88.31% of the variation in green fodder yield. The high direct contribution of fresh stem weight should be interpreted cautiously because it constitutes a major component of green fodder yield. The study identified fresh stem weight, dry fodder yield, dry matter content, leaf length, and branching traits as key selection criteria for improving fodder productivity and developing superior fodder cowpea cultivars.