Agronomic Evaluation of Castor Bean Cultivation (Ricinus communis L.) Under Soil Moisture-Limiting Conditions

Objective: To assess yield and growth responses of castor bean collections under soil moisture-restricted conditions. Design/methodology/approach: The study was conducted in the municipality of Salinas de Hidalgo, San Luis Potosí. Twenty castor bean collections were evaluated under rainfed conditions and irrigation at 50% of crop evapotranspiration, with treatments arranged in randomized blocks. Results: Significant differences (α = 0.05) between collections were observed for variables such as stem diameter, plant height, number of clusters per plant, number of fruits per cluster, 100-seed weight, and aerial biomass. Regarding soil moisture levels, variables including stem diameter, plant height, number of branches, number of leaves, number of clusters, number of fruits per cluster, 100-seed weight, seed yield, and aerial biomass showed significant differences (α = 0.05). Limitations on study/implications: The results are based on a single production cycle. Findings/conclusions: The Calvillo and Encarnación de Díaz collections showed the highest seed yields under rainfed conditions, with 385 and 326.7 g/plant, respectively, while the Luis Moya collection exhibited the highest yield under irrigation, with 680.7 g/plant. Seed yield was influenced solely by soil moisture, independent of collection origin. Collections under the most restrictive soil moisture condition (rainfed) flowered and fruited slightly earlier.