Response of soybean (Glycine max L.) genotypes to levels of phosphorus for rooting and nodulation characteristics on acidic soils of Western Ethiopia

Abstract

Dense and deep root systems are desirable traits in maintaining the tolerance of soybeanto adverse edaphic factors; while high and effective nodulation are important inimproving soil fertility. The study was conducted to assess the response of soybeangenotypes to varying phosphorus (P) levels for important root and nodulationcharacteristics across three locations of Western Ethiopia (Jimma, Assossa, and Mettuexperimental sites), which are soil acidity prone areas. Treatments were laid out in split-plot design, where levels of P and genotypes (G) were main plots and sub-plots,respectively. The study comprised of 36 soybean genotypes and three levels of P (0, 100,and 200 kg ha -1 of P in the form of TSP). The results revealed that G X P interactionswere significant for number of nodules and total nodule weight at Jimma, and Assossa;while root weight and root volume were significant at Mettu. Genotypes showedsignificant difference for all the parameters, except for number of nodules and totalnodule weight. Significant and positive correlations were found between root traits,such as root volume and tap root length with grain yield at low P, reflecting theimportance of these traits to improve productivity of soybean on P starved soil. Totalnodule weight showed highly significant correlations with grain yield at 100 kg ha -1 .Both the mean separation and cluster analysis indicated that genotype PR-142 (26) wasthe best genotype, and AGS-3-1, SCS-1, AGS 234, and H3 performed well for most of thestudied traits