Özet:

36 durum wheat varieties released since 1966 were evaluated in three replications of the Alpha lattice Design at DebreZeit and Akaki, Ethiopia during the 2016 cropping season to estimate the amount of genetic gain made over time in grain yield potential,yield-associated traits and in protein content. Analysis of variance revealed significant differences among varieties for all 16 quantitative traits, protein content and protein harvest in Kg ha-1 at each of the locations.Grain yield was increased from 2705.92kg ha-1 to 3766.67.4kg ha-1 over the past 49 years. Regression analysis revealed that grain yield has increased by 22.24 kg ha-1 year-1 with relative genetic gain of 0.83% year-1 for the period of 1966- 2015. A significant decline of 11.4% in spike length, 6.7% in spikelets spike-1, 17.9% in protein content and 31.2% in protein yield ha-1 and a significant increase of 41.1% in grains spikelet-1, 32.9% in number of grains spike-1, 22.3% in thousand grain weight, 17.8% in grain filling period, 23.9% in seed growth rate, 40.1% in grain yield production rate, 7.9% in harvest index, 6.5% decrease in days to flowering and a 1.0% extension in days to maturity were statistically nonsignificant, this has significantly extended the grain filling period. Plant height, Tilleers plant-1, biomass production rate, hectoliter weight and biomass yield ha-1 have remained unchanged over the 50 years of durum wheat improvement.

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