Unraveling Yield Performance and Nutritional Trait Architecture in Quinoa (Chenopodium quinoa Willd.) Using Integrated Variability, Correlation and Path Analysis

Improving crop yield and nutritional quality requires a clear understanding of the magnitude of genetic variability and the nature of relationships among component traits. The present investigation evaluated thirty-six quinoa genotypes to assess genetic variability, heritability, genetic advance, and associations among yield and nutritional traits using correlation and path coefficient analysis under a replicated experimental design. Highly significant differences among genotypes were observed for all fourteen traits studied, indicating substantial genetic variability. Phenotypic coefficients of variation were generally higher than genotypic coefficients, reflecting environmental influence, although the narrow differences for several traits suggested stable genetic expression. High heritability coupled with high genetic advance for seed yield, biological yield, inflorescence traits, protein content, lysine content, and saponin content indicated the predominance of additive gene action and the effectiveness of direct selection. Genotypic correlations were consistently higher than phenotypic correlations, revealing strong inherent genetic associations among traits. Path coefficient analysis identified biological yield per plant as the most influential trait exerting the highest positive direct effect on seed yield, followed by harvest index and inflorescence traits, while nutritional traits showed negligible direct effects on yield. Overall, the integrated use of variability parameters, correlation, and path analysis provides a comprehensive understanding of trait behaviour and identifies reliable selection criteria for simultaneous improvement of yield and nutritional quality in quinoa.