Genotype X Environment Interactions and Stability of Soybean for Grain Yield and Nutrition Quality

Soybean Glycine max (L.) Merrill] is the world’s leading source of oil and protein. It has the highest protein content of all food crops and is second only to groundnut in terms of oil content among food legumes. Study on genotype x enviroment interaction (GE) and stability of twenty soybean [Glycine max (L.) Merrill] genotypes was conducted for grain yield, oil and crude protein content at six environments in 2007. The objectives of the experiment were to determine the magnitude of GEI and stability of released and elite soybean genotypes and thereby identify widely and/or specifically adapted genotypes under Ethiopian conditions. There are strong significant (P<0.01) environment, genotype and GEI effects, and environment and GEI captured larger portion of the total sum of squares, which reveals the influence of the two factors in evaluating soybean genotypes and, hence, the need for stability analysis. Three most popular stability parameters were used for stability analysis. Three genotypes that had medium yield performance, IPB-144-81(p), Braxton and Awassa-95, were identified as stable genotypes for grain yield. The three top yielding genotypes, AGS-115-1, TGX-297-6f-1 and AGS-162, were found unstable and can be recommended for narrow adaptation to Gofa, Areka and Inseno, respectively. Haddee-1 and Braxton were genotypes with high oil content and showed stable performance across the environments. TGX-297-6f-1 had high oil content but unstable with specific adaptation to Bonga. Clarck-63k had the highest crude protein content and also very stable one. IPB-144-81(p) and AFGAT had high crude protein content but very unstable and specifically adapted to Areka.