Genotype × Environment Interaction and Stability Analysis of Root Traits in Turnip (Brassica rapa Subsp. rapa)

An experiment was conducted to evaluate the performance and stability of twenty-five turnip (Brassica rapa subsp. rapa.) genotypes collected from diverse agro-climatic regions of India. The study was carried out during the rabi season of 2024 at three locations in Kashmir which are at different altitudes. The experiment was laid out in a complete randomized block design with three replications at each location. Observations were recorded for plant height, leaf area, plant spread, root length, root breadth, net root weight, root compactness, harvest index, and root yield per hectare. The genotypes exhibited substantial variation across locations for all recorded traits. Analysis of variance indicated highly significant differences among genotypes, reflecting the presence of considerable genetic variability and the scope for improvement through selection. Genotype × environment interaction effects were also significant for all traits, demonstrating differential genotypic responses under varying environmental conditions. The wide range of variability observed across traits highlights the potential for targeted selection to improve yield, quality, and stability in turnip breeding programmes. Among the three test environments, E1 (Vegetable Experimental Farm, Shuhama) was the most favourable for the expression of most economic traits. Maximum root length was recorded in genotypes SKAU-B-T9 and SKAU-B-T12, while the highest root breadth was also observed in these genotypes. SKAU-B-T9 followed by Nageen recorded the highest net root weight, whereas the maximum root yield per hectare was obtained from SKAU-B-T9 and SKAU-B-T12, indicating their superior performance under favourable environmental conditions. Stability and adaptability of genotypes across environments were assessed using the Eberhart and Russell (1966) model, which considers mean performance, regression coefficient, and deviation from regression. The stability analysis revealed that genotypes SKAU-B-T7, SKAU-B-T10, SKAU-B-T17, and SKAU-B-T22 exhibited moderate stability for economic traits such as root yield per plant and root yield per hectare, indicating their relatively consistent performance across environments.