Growth, Yield and Yield Components Response of Local Sorghum Varieties to Nitrogenous Fertilizer Rates in Northern Ghana

In the resource-constrained, rain-fed farming communities of northern Ghana, sorghum (sorghum bicolor L. Moench) remains an important cereal crop for food security. Yield of sorghum, however, remains below 700 kg/ha due to lack of knowledge on relative performance of local varieties under different fertilization regimes. To help improve upon the yield of the crop, field experiments were conducted at Vea in the Upper East region during the 2014 and 2017 cropping seasons to assess the effect of N fertilizer rates on growth and yield of local varieties to determine the best local sorghum variety that respond effectively to the most economical N fertilizer rates. The treatments comprised factorial combination of six nitrogen rates (0, 30, 60, 90, 120 and 150 kg N /ha) and three local sorghum varieties (Bawku red, Kamolg and Kadaga) tested in a Randomized Complete Block Design with four replicates. Data were collected on growth, yield and yield components of the crop and analyzed using two-way analyses of variance procedure, where means were separated at probability of 5%. From the results, there were no significant interaction effect (p > 0.05) of N rates and sorghum varieties on most parameters studied. However, there were significant effect (p < 0.05) of N rates on plant height, leaf number, aboveground biomass, panicle length, number of branches, number of florets, number of seeds, 200 hundred seed weight and total weight of panicle; each increasing with increasing N rate with optimum occurring at 90 kg/ha N. Significantly higher grain yield was obtained in response to the application of 60 and 90 kg/ha N for the Kalmolga variety in comparison with other varieties and N-rate combinations. As Kamolga variety accrued the highest yield (1270 kg/ha) at N rate of 90 kg/ha, this combination is recommended to the resource-poor, sorghum farmers of northern Ghana.

Keywords: Sorghum varieties growth; Nitrogen fertilizer rates; Yield and yield components

Abbreviations: ANOVA -Analysis of Variance; CV - Coefficients of Variation; WAP - Weeks After Planting; N – Nitrogen; LSD - Least Significant Difference; kg – Kilogram; MG – Milligram; t/ha - Ton per hectare; T – Treatment; FWOB - Fresh Weight of Biomass; DWOB - Dry weight of Biomass; G – Gram; HA-1 - Per Hectare; Kg/ha - Kilogram per hectare; WRC - Water Resource Commission; WASCAL - West Africa Science Center on Climate Change and Adapted Land Use; DAE - Days after Emergence; % - Percentage