Agronomic Yield Performance of Rape and Assessment of Discrimination of Soil Fertilizer Amendments on Genotypic Responses

Aim: The objectives of the study were to (i) assess agronomic performance of rape (Brassica napus L.) genotypes under different soil amendments and seasons and (ii) identify the most discriminating soil fertilizer amendment on genotypic responses of rape. Study Design: The experiment was laid as a split plot design with 3 replications in each season. Place and Duration of Study: The study was undertaken in Monze district, southern province, Zambia in winter and summer periods of 2020/2021 cropping season. Methodology: The soil fertilizer amendment combinations were the main plots and rape varieties (English Giant [ENG], Hobson [HOB] and Rampart [RAM]) were laid as subplots. Giving a total of 54 experimental units per season. The amendments constituted combinations of raw dung type and artificial fertilizer. The quantitative data, on biomass, breadth, height and leaf count were measured at six weeks after transplanting. Results: Across seasons, soil amendment and genotypic main effects exhibited significantly responses with regards to biomass and leaf count (P = 0.05). Furthermore, the agronomic genotypic performance showed that RAM was the worst performer. The genotypic response to measured agronomic parameters was better in Raw Cow-Dung plus Cow- Dung Ash (RCD + CDA) soil fertilizer amendment than others. Interestingly RCD + CDA was the common discriminating amendment in summer and winter trials. Conclusion: Rape genotypes performed relatively better in summer than in winter season. The genotype English giant rape and Hobson were better performers across seasons and soil fertilizer amendments. The combination of RCD + CDA was the common discriminating amendment in both summer and winter trials.