Correlation, Path and Heatmap Analyses Reveal Genetic Determinants of Yield and Oil Quality in Mustard

Abstract

The present study aimed to elucidate the genetic determinants of yield and oil quality traits in Brassica
juncea through correlation, path coefficient, and heatmap analyses. Twenty-five genotypes were
evaluated during Rabi 2025 under a randomized block design with three replications at Acharya
Narendra Deva University of Agriculture and Technology, Ayodhya, India. Significant genetic
variability was observed for all studied traits, including plant height, number of siliquae per plant, seeds
per siliqua, biological yield per plant, harvest index, erucic acid content, and seed yield per plant. High
heritability coupled with substantial genetic advance was recorded for erucic acid (h² = 0.99; GA% =
102.15), seeds per siliqua (h² = 0.99; GA% = 84.01), and siliquae per plant (h² = 0.99; GA% = 80.15),
indicating strong additive gene action and potential for effective selection. Phenotypic correlation
analysis revealed that harvest index (r = 0.65) and biological yield (r = 0.72) were positively associated
with seed yield, whereas erucic acid showed a weak negative correlation (r = –0.29), suggesting that oil
quality improvement may not compromise yield potential. Path coefficient analysis confirmed that
biological yield (direct effect = 0.7441) and harvest index (0.9874) exerted the strongest direct influence
on seed yield, while erucic acid had a minor negative effect (–0.0019). Clustered heatmap analysis
further demonstrated distinct grouping of yield-related and oil-quality traits, indicating that simultaneous
improvement of both is feasible. Overall, the integration of multivariate analyses provided a
comprehensive understanding of trait interrelationships, offering valuable insights for breeding high-
yield, low-erucic acid mustard cultivars suitable for edible and industrial applications.