Abstract Background Thirty-nine F7 new lines selected were evaluated alongside ten checks for pod yield, earliness, tolerance to diseases and other agronomic traits in the major and the minor seasons in 2014. The study locations were Fumesua in the forest ecological zone and Ejura in the forest-savanna transition ecological zone. The trials were laid out in lattice square (7 × 7) design with three replications. Results Genotype by environment interaction (G x E) was significant (p Conclusion The observed variations due to location effects for all the traits studied revealed that the genetic expressions of these parameters were influenced by the prevailing environmental condition. Ten improved lines were selected for on-farm evaluation based on pod yield performance (1.3–1.5 ton/ha), tolerance to diseases and early maturity (89–92) days.