Effect of Inter Row Spacing on Yield Components and Yield of Soybean [Glycine Max (L.) Merrill] Varieties in Dale Sedi District, Western Ethiopia

Soybean is an important crop in the tropical, hot sub-moist agro-ecological zone of western Ethiopia.However, the yield of the crop is limited due to lack of appropriate plant density for the varieties.Therefore, the experiment was conducted to determine the effect inter row spacing on growth, yield components and yield of soybean varieties during 2016 cropping season in Dale Sedi District, western Ethiopia.Four inter row spacing (30, 40, 50 and 60cm) were evaluated on three soybean varieties (Nyala, Wello and Dhidhessa).The experimental design was randomized complete block design in factorial arrangement with three replications.Highly significant differences were obtained on days to 50% flowering, days to 90% physiological maturity, plant height and hundred grains weight (g) due to the main effect of the variety.Variety Nyala was earlier in attaining flowering (57.12 days), physiological maturity (115.6 days), variey Wello was the longest (84.70cm) and variety Nyala gave higher hundred grain weight (19.91g) than varieties Wello and Dhidhessa.The interaction effect of variety and inter row spacing were highly significant on number of primary branches, on crop stand count percentage at harvest, grain yield and harvest index, number of pods per plant, grain yield and harvest, where the highest numbers of primary branches per plant (4.57) and highest number pods per plant (49.83) were recorded for variety Wello at 60 cm, inter row spacing and the highest crop stand count percentage(99.77), the highest grain yield(3805kgha-1) and the highest harvest index (52.40%)were recorded from variety Nyala at 40 cm, inter row spacing.However, this tentative generalization based one season at one location requires further studies over years and locations to give a valid recommendation.