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Grain yield, oil content and other related traits of linseed (Linum usitatissimumL.) have been improved in the country over the last 25 years through breeding and other improved production techniques. The objective of this study was to estimate the genetic progress made in improving grain yield, oil content and associated traits. The experiment was conducted at Hossaina, Kokate, Dida-Midore and Holeta in 2009/10. A randomized complete block design with four replications was used. Nine released cultivars from 1984 to 2009, three pipeline varieties, and one local cultivar were used as testing materials. Among many others, the major traits that were analyzed in this study include grain and oil yields, oil content, thousand seeds weight, number of capsules per plant and seeds per capsule. Regression of trait means against the year of release indicated that thousand seeds weight and number of capsules per plant exhibited significant (P ≤ 0.05) changes while the others being nonsignificant since 1984. However, dramatic and highly significant (P ≤ 0.01) progress was observed in major traits such as grain and oil yields, oil content and thousand seeds since 1992 and furthermore since 1997. The estimated rates of increases per year were 4.33, 9.78 and 10.45 kg ha-1for grain yield, 2.01, 4.59 and 5.00 g ha-1for oil yield, 0.05, 0.10 and 0.12% for oil content, 0.033, 0.057 and 0.06 g for thousand seeds weight and 0.11, 0.15 and 0.18 capsules per plant since 1984, 1992 and 1997, respectively. These significant and linear genetic gains showed that there is no indication of a yield plateau for linseed breeding in Ethiopia. Therefore, the effort should be strengthened and continued to achieve more progresses in these and other relevant traits. |
