Genetic variability and associations among yield and yield‐related traits in Ethiopian linseed ( <i>Linum usitatissimum</i> L.) landraces

Abstract

Abstract Linseed ( Linum usitatissimum L.) is a key oilseed crop in Ethiopia's central highlands. However, its productivity is constrained by the limited availability of high‐yielding varieties, highlighting the importance of investigating genetic variability and trait associations among local landraces. With this in mind, the present study assessed genetic variability and trait associations for yield and yield‐related characteristics in Ethiopian linseed genotypes. Forty‐nine genotypes including four released varieties and 45 accessions were evaluated in a 7 × 7 simple lattice design at Debre Berhan, North Shewa of Ethiopia, during the 2018 main cropping season. Analysis of variance revealed significant differences among genotypes for all traits except the number of primary branches per plant and the number of tillers per plant, indicating substantial variability and strong potential for improving the desirable traits through selection. The phenotypic coefficient of variation ranged from 6.74% for days to maturity to 91.49% for oil yield ha − 1 , whereas the genotypic coefficient of variation ranged from 3.66% for oil content to 45.26% for secondary branches per plant. Broad‐sense heritability varied from 34.75% for oil yield to 90.28% for seed yield, while genetic advance as a percentage of the mean ranged from 7.55% for oil content to 99.61% for the number of secondary branches. High heritability coupled with high genetic advance was observed for the number of secondary branches (82.12%, 99.61%), plant height (84.97%, 36.86%), and capsules per plant (85.72%, 56.5%), suggesting that these traits are largely under genetic control and can respond effectively to selection. At both phenotypic and genotypic levels, seed yield per hectare showed significant positive correlations with the number of secondary branches per plant, oil yield, harvest index, 1000‐seed weight, and seed yield per plant, while days to maturity displayed a strong negative correlation with seed yield. Path analysis indicated that biological yield, oil yield, days to maturity, number of secondary branches, 1000‐seed weight, and harvest index exerted substantial indirect effects on seed yield at the genotypic level. Overall, these findings suggest that breeding should focus on traits with high heritability coupled with high genetic advance, particularly secondary branches, plant height, and capsules per plant, to improve yield. High‐performing genotypes such as Acc 10059, Acc 242592, Acc 233992, and Acc 242588 merit further multi‐environment testing and use as parents in variety development.