Multivariate Cluster and PCA Biplot Analysis of Yield and Oil Quality Traits in Brassica juncea

Abstract

Indian mustard (Brassica juncea) is a major oilseed crop in India, contributing significantly to edible oil
production and nutritional security. Despite its importance, productivity remains below the global
average, necessitating genetic improvement for both yield and oil quality traits. In this study, 25
genotypes of B. juncea were evaluated during Rabi 2025 for seven quantitative traits, including plant
height (PH), number of siliquae per plant (NSPP), seeds per siliqua (SPS), biological yield per plant
(BYPP), harvest index (HI), seed yield per plant (SYPP), and erucic acid (EA). Erucic acid content was
estimated using GC-FID, while multivariate statistical approaches such as cluster analysis and principal
component analysis (PCA) were employed to assess genetic divergence and trait associations. Cluster
analysis revealed three distinct groups, with Cluster III showing the highest NSPP (185.70) and SYPP
(22.87), along with the lowest EA (27.18), making it the most promising for simultaneous yield and oil
quality improvement. Cluster I exhibited the highest HI (39.88) but elevated EA (50.16), suggesting its
utility as a donor for partitioning efficiency. PCA indicated that the first three components explained
75.25% of the total variation, with PC1 dominated by PH, NSPP, and SYPP, while PC2 highlighted HI
and SPS. Erucic acid loaded strongly on PC4, confirming its independence from yield-related traits. The
PCA biplot further demonstrated clear differentiation among genotypes, with yield traits clustering
together and EA positioned separately. Overall, the combined application of cluster analysis and PCA
provided robust insights into trait architecture, confirming that yield efficiency can be enhanced through
siliqua traits and harvest index, while oil quality improvement via reduced erucic acid can be achieved
independently. These findings offer valuable guidance for breeding strategies aimed at developing high-
yielding, low-erucic mustard varieties suitable for diverse agro-ecological zones.