Correlation and path analysis in rapeseed (Brassica napus L.) genotypes under heat stress condition

Abstract

This investigation assessed the genetic potential of 20 rapeseed genotypes under heat stress during the Rabi season 2020–21 at Sindh Agriculture University, Tandojam, using a randomized complete block design with three replications. Seven agronomic traits were evaluated: plant height, branches per plant, siliques per plant, silique length, yield per plant, seed index, and oil content. All traits exhibited significant variation, indicating broad genetic diversity. Punjab Sarson outperformed others in multiple traits, while PARC Canola, Hbo-555, and Faisal Canola showed high seed yields under stress. Significant positive correlations with seed yield per plant were found for plant height (0.349**), siliques per plant (0.610**), silique length (0.319*), seed index (0.313*), and oil content (0.266*). Path analysis revealed that siliques per plant (1.792) and oil content (2.379) had the strongest direct effects on seed yield, making them effective targets for selection. However, heritability for all traits was low under heat stress, suggesting that selection should be delayed until later segregating generations for better genetic gain.

Key words: Correlation, rapeseed, path analysis, heat stress, heritability