ON-STATION EVALUATION OF SOYBEAN (Glycine max (L.) Merill) MUTANT GENOTYPES FOR IMPROVED AGRONOMIC TRAITS IN NORTHERN GHANA

Abstract

Soybean [Glycine max (L.) Merrill] is an important oilseed crop in the world. Despite the important role soybean plays in the achievement of nutritional security in low income families, its production is low due to relatively long maturity period, pod shattering, low yield, poor quality oil, low resistance to diseases and abiotic stresses. Previous studies in the Department of Agronomy of the University for Development Studies have resulted in the production of mutant genotypes with desirable agronomic traits. In the present study, these soybean mutant genotypes were evaluated in three agro-ecological zones – Transition, Guinea Savannah, and Sudan Savannah zones of northern Ghana. The soybean genotypes used for the study were 150 Gy, 200 Gy, 250 Gy, and 300 Gy mutants and the un-irradiated (0 Gy) which served as control. Fertilizer application rates of 0 kg/ha, 45 kg/ha, 60 kg/ha, and 75 kg/ha of Triple Super Phosphate (TSP) were applied three weeks after planting. The treatment combinations were replicated 3 times in each agro-ecological zone resulting in a 5 x 4 x 3 factorial experiment and laid out in Randomized Complete Block Design (RCBD). Data were taken on agronomic and yield parameters and analyzed. The results showed that with the exception of plant height, the 0 Gy and 300 Gy recorded the lowest values of traits measured. The 150 Gy, 200 Gy and 250 Gy mutants recorded significant improvement in terms of agronomic and yield traits. The 150 Gy, 200 Gy, and 250 Gy mutants recorded higher grain yields than the 0 Gy and the 300 Gy. The 200 Gy and the 250 Gy genotypes are therefore recommended for on-farm evaluation prior to their release for commercial production.