Response of Mungbean (Vigna radiataL Wilczek) Genotypes to Different Spacing Types in Derived Savannah Agroecology of Southeast Nigeria

Population density is an important determinant of crop yield. For optimum crop production, the best spacing requirement must be  adopted. Although the recommended spacing requirement of mungbean is abundant in literature globally, there is no such information  on studies conducted within derived savannah agroecological zone of southeast Nigeria, despite the crop’s usefulness as food, green  manure, and nitrogen fixer. We hypothesized that the spacing requirement of mungbean may vary with genotype. Hence, this study was  conducted to evaluate the response of three mungbean genotypes to four spacing types in derived savannah agroecology. The  experiment was a split-plot design with genotype (Tvr18, Tvr65, and Tvr83) as the main plot treatment and plant spacing (30x10, 40x10,  30x15, and 40x15 cm) as the sub-plot treatment. Data were collected on 19 agronomic traits. Analysis of variance (ANOVA) showed that  plant spacing of 30x10 cm influenced significantly higher (p<0.05) values in most agronomic traits measured while Tvr18 was higher in  pod and seed attributes with higher seed-yield (0.80 t/ha) compared to Tvr83 (0.52 t/ha) which was the least. The interaction effect of  Tvr18 by 30x10 cm gave a higher seed yield of (1.37) t/ha compared to Tvr83 by 30x10 cm (0.62 t/ha) which was the least. GGE biplot  analysis showed a higher seed yield of the genotype-Tvr83 with wider spacing 40x15 compared to 30x10 cm.