Multi-environmental evaluation of vegetable soybean for adaptation and stability in Benin

Vegetable soybean (Glycine max L. Merr.) is a highly nutritious crop in Africa whose attributes make it a product of choice to formulate diets with numerous human health benefits. The crop is still novel in West Africa, but is making inroads in many countries of the region. The objective of this study was to evaluate selected vegetable soybean varieties for agronomic performance and stability for fresh pod yield across Benin. Thirty-five vegetable soybean varieties were planted at three locations, namely Calavi, Grand-Popo and Sèmè, for two seasons. There was a significant variation (P < 0.05 ; P< 0.01 and P < 0.001) among genotypes for most quantitative traits; with highly significant environmental (P < 0.001) and GEI effects on fresh pod yield (P < 0.001). Genotype Maksoy 3N (15.9 t ha-1) had the highest fresh pod yield; while genotype AGS466 was the most stable across environments. Based on GGE, Sèmè-2 was the ideal environment for growing vegetable soybean in Benin. The study confirmed that vegetable soybean is well adapted to be grown in Benin and varieties AGS466, AGS346 and Ashorowase are candidates for wide cultivation in the country. Also, grain soybean varieties (S1079-6-7 and Maksoy 3N) are well suited to produce vegetable soybean in Benin.