Characterization of linseed (Linum usitatissimum L.) germplasm for genetic diversity and G x E interaction

A comprehensive evaluation of 60 linseed (Linum usitatissimum L.) genotypes was conducted across two contrasting agro-ecological locations—Ludhiana and Gurdaspur—using 10 key agro-morphological traits to assess genetic variability, heritability, genetic advance, and genotype × environment (G × E) interaction. Analysis of variance (ANOVA) revealed significant differences among the genotypes for all traits, confirming the presence of substantial genetic variability. High estimates of phenotypic and genotypic coefficients of variation (PCV and GCV), heritability (H²), and genetic advance as percent of mean (GAM) were recorded for traits such as number of secondary branches, capsules per plant, and seed yield, indicating strong additive gene action and their suitability for selection in breeding programs. In contrast, traits like days to 75% maturity and 1000-seed weight exhibited low variability and heritability, suggesting stronger environmental influence. Combined ANOVA and GGE biplot analysis identified significant G × E interactions, with genotype BAU-2019-13 showing superior performance in Ludhiana and LCK-2134 in Gurdaspur. Dendrogram-based clustering using Ward’s method grouped the genotypes into six distinct clusters at each of the locations, revealing considerable genetic divergence. Smaller, isolated clusters contained highly divergent genotypes suitable for hybridization, while larger clusters suggested potential for intra-population selection. The study highlights the importance of multi-environment testing and advanced multivariate tools such as GGE biplot and cluster analysis in identifying stable, high-yielding genotypes and guiding targeted breeding strategies for linseed improvement.