Flax (Linum usitatissimum L.) is a widely adapted oilseed crop which, based on the genotype, its oil could be used in industry or as edible oil. Oil of regular genotype of flax is used in industries as drying oil, because of a high amount of linolenic acid content (>50%). However, oil of new, mutant genotypes of flax is of a very low content of linolenic acid (<2%), is similar to sunflower oil in terms of fatty acid composition and thus can be used as edible oil. This experiment was conducted to investigate agronomic traits, genetic variation and relationships between the traits in 100 isolated lines from a landrace variety of flax in Isfahan using an Augmented Design. The results showed that there was a high genetic variation for number of seedlinges/m2, number of capsules/plant, seed yield/plant, seed yield per unit area and the growth type. The oil content which was measured in 20 superior lines by Soxhlet method varied from 36.2 to 40.5 % .The estimation of narrow-sense heritability by parent-offspring regression showed that plant height was of the highest heritability (40%), whereas number of branches/plant and seed yield/plant had the lowest (12.5%) heritability. Cluster analysis based on the agronomic traits classified the genotypes into 5 groups which had significant differences for all the traits except for seeds/capsul, seed weight and days to flowering. Two groups of genotypes had the maximum seed yield/plant as well as seed yield/m2 ,but had a minimum number of seedlinges/m2. It seems that flax plant possesses a good potential for conpensation of seed yield through more branching as well as production of more capsules/plant. Correlation coefficients showed that seed yield/plant had a high positive correlation with number of capsules/plant (r=0.92**) but a negative correlation with seedlings/m2 (r=-0.53**). Also, seed yield had a high positive correlation with seed yield/plant (r= 0.62**). Path analysis revealed that number of capsules/plant had the most direct and positive effect on seed yield/plant. Based on regression analysis, the most important components of seed yield/plant were recognized as number of capsules/plant and seeds /capsule which approximately contributed to 85% and 9% of seed yield /plant variation, respectively.
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