Multivariate Correlation and Fit for Path Analysis of 25 African Yam Bean (Sphenostylis stenocarpa) Accessions Using Structural Equation Models

Among the 6474 neglected legume germplasm held by the Genetic Resource Centre, International Institute of Tropical Agriculture with excellent nutritional content and no approved variety is African yam bean (AYB) (Sphenostylis stenocarpa Hochst. Ex A. Rich) Herm. This study aimed to use structural equation model (SEM) to show how traits affect AYB seed yield production. A field experiment was conducted in 2021 and 2022 across three locations, using three replications in a randomized complete block design with 25 accessions of AYB. Correlation and path analysis in a covariance SEM was used to uncover and choose strong connections between seed yield and nine yield-related parameters to show real linkages. Statistical analysis of variance on 10 attributes was performed for correlation. Results showed SEM combination of comparative fit index (CFI) >0.95, standardized root mean square residual (SRMR) <0.08, and root mean square error of approximation (RMSEA) <0.06. There were 18 genotypic-phenotypic connections with seed yield, 7 of which were negative and 11 positive. Peduncle length (rg = 1.000) and pod length (rg = 0.597) had stronger genotypic correlation than phenotypic correlation, except seeds per pod (rp = 0.286 > rg = 0.079) with seed yield. Path analysis yielded 41 RMSEA and SRMR associations, 26 of which were eliminated and 15 chosen for improvement. A large modelling range of -3.846 to 39.377 in critical ratio was selected in direct relationships (CFI >0.95), indicating good SEM dependability in crop development. Locus cavity (r = 0.82) was stronger than peduncle length in predicting seed production.