Connecting the Dots: Investigating Epistatic Relationships in the Manifestation of Heterosis in Industrial Oilseed crop Brassica rapa var yellow sarson

This study delves into the role of epistasis in elucidating heterosis manifestation in Brassica rapa var. yellow sarson hybrids. Four hybrids—YSH-0401 × Pant Sweta (C1), Pant Sweta × Apetalous (C2), PYS 2017-6 × PPS-1 (C3), and NDYS-107 × B-9 (C4)—were meticulously evaluated for seven key traits. Heightened plant stature, consistent across generations, and increased siliqua per plant with elongated siliqua length characterize the observed heterotic expression.Epistasis analysis, utilizing a six-parameter model, reveals significant additive, dominance, and epistatic interactions. Scaling tests affirm the presence of all three epistasis types (i, j, l) across diverse crosses and traits. Dominance × dominance (l) emerges as a pivotal factor, guiding heterotic expression and offering strategic breeding insights.Gene action assessment highlights patterns of duplicate gene action, complementary epistasis, and dominance variance, influencing selection strategies and breeding timelines. The correlation between heterosis and epistasis components underscores the significance of dominance × dominance in shaping superior hybrid performance. These findings contribute valuable insights to the scientific discourse on enhancing Brassica Rapa var Yellow sarson hybrid productivity, emphasizing the potential of selective mating to strategically leverage dominance and epistasis effects for optimized yields in plant breeding.