Trait-Based Genetic Variability of Linseed Genotypes for Seed Yield and Yield Components in West Shewa, Ethiopia

Linseed ( Linum usitatissimum L.) is a significant oilseed crop in the central highlands of Ethiopia, where breeding efforts primarily focus on enhancing seed yield through the exploitation of genotypic diversity. However, progress has been hindered by the limited availability of superior varieties. This study aimed to assess the genetic diversity and trait associations among 35 linseed genotypes for key agronomic traits. The experiment was conducted during the 2023 main cropping season using an alpha lattice design. Analysis of variance (ANOVA) revealed highly significant differences (P ≤ 0.01) among genotypes for all 14 agronomic and yield-related traits, indicating substantial genetic diversity. The results showed wide ranges in traits such as days to maturity, number of capsules per plant, seed yield, and oil content. Estimates of genetic parameters showed high phenotypic and genotypic coefficients of variation (PCV and GCV) for traits such as tiller number, harvest index, seed yield, oil yield, and oil content, indicating potential for effective selection. Broad-sense heritability was high (> 90%) for most traits, indicating strong genetic control and high expected genetic gain. Principal Component Analysis (PCA) revealed that the first five components explained 77% of the total variation, with oil yield, seed yield, biomass, and plant height being major contributors. Cluster analysis grouped genotypes into five distinct clusters, highlighting significant inter-cluster genetic distances, especially between clusters III and V, which could be valuable for hybridization. Correlation analysis indicated significant positive associations among seed yield, oil content, and harvest index, while lodging was strongly correlated with plant height and maturity. The overall results underscore the presence of exploitable genetic variability among the tested linseed genotypes, providing a solid foundation for future breeding efforts to improve yield and adaptability.