Abstract:

The study was conducted to assess the effect of intra-row spacing on the incidence and severity of viral disease on soybean during the wet cropping season in 2019 at the National Cereal Research Institute (NCRI), Mokwa field, located in the Southern Guinea savanna of Nigeria at an altitude of about 212 metres above sea level. Observation and data collection were done on the disease incidence and severity rating; also, plant height, the number of leaves, the number of pods per plant, the number of seeds per pod and Grain yield (t/ha) were determined at harvest. Data collected on growth and yield parameters were subjected to analysis of variance (ANOVA) using the general linear model (PROC GLM) procedure of SAS (2008). The means of significant (p≤0.05) F-test were separated using the Least Significant Difference (LSD) at a 5% probability level. The Elisa results obtained revealed the presence of Cowpea mottle virus, Cowpea yellow mosaic virus and Soybean mosaic virus. Also, the field trial showed that the different spacing and soybean cultivars investigated differ significantly on the variables tested. However, optimum spacing at 20 cm and 1448 - 2E had significantly (P<0.05) increased in all vegetative, reproductive growth and yield as well as reduced incidence of the soybean viruses detected in the field. From the above results, spacing at 20 cm with the cultivation of soybean cultivar 1448 - 2E and appropriate cultural practices are hereby recommended to farmers in the area.