EVALUATION OF ELITE SOYBEAN (Glycine max (L) Merril) GENOTYPES FOR NITROGEN NUTRITION, WATER USE EFFICIENCY AND GRAIN YIELD IN THE GUINEA SAVANNA AGRO ECOLOGICAL ZONE OF NORTHERN GHANA

Abstract

Nitrogen is very essential for every crop production due to its function in plant growth and development. It is an essential component of DNA and proteins which are the building blocks of life. Notwithstanding its vast importance, nitrogen is worldwide considered as one of the most limiting factors of production. The need to meet the huge nitrogen requirement has necessitated the use of synthetic fertilizer which continued application affects soil health, environment and agricultural sustainability. Identifying breeding lines and developing new legume crop varieties that have the ability to fix enough atmospheric nitrogen and integrating these varieties into the farming systems is a best alternative to reduce the harmful effects that are occasioned by the continued application of the synthetic fertilizers. A field experiment was conducted at the CSIR-Savanna Agricultural research Institute research fields using 20 elite lines under rain fed condition. The objective of the study was to select soybean (Glycine max (L.) Merril) elite lines for improved nitrogen fixation, water use efficiency and grain yield. A randomized complete block design was used with three replications. Data collected include; the amount of nitrogen fixed, nitrogen derived from the atmosphere, and grain yield. The nitrogen (N) difference technique was used. The genotypes showed statistically significant variability for Amount of N-fixed, percent nitrogen derived from the atmosphere and grain yield. The mean symbiotic N contribution of the genotypes ranged from 53.6 Kg/ha – 370.5 Kg/ha. Also, the grain yield of the genotypes were observed to be significantly different among the genotypes. Genotypes, SAR-SL2/SPG-18-4, SAR-SLI1/USL-18-2, SAR-SL2/USL-18-1, Favour, and FT Cristaline showed superior performance for N-fixed and grain yield. There was high heritability observed amongst the selected traits and high phenotypic coefficient of variation and genotypic coefficient of variation which is required in breeding program for crop improvement. The research suggested that the genotypes should be re-evaluated in multi-locations and if they perform same they can be considered for release as varieties.