Evaluation of growth and yield performance of sesame (Sesamum indicum L.) landraces under varying planting dates

This study explored how sowing dates impact development, phenology, and yield of sesame, an important oilseed crop with substantial nutritional, economic, and livelihood value to Zimbabwe’s smallholder farmers. The study addresses the persistent issue of low sesame productivity, a problem driven by erratic rainfall patterns from climate change and a shortage of agronomic advice on optimal planting times. Our field study was conducted in Chiundura Communal Area, using a 3 × 2 factorial arrangement in a Randomized Complete Block Design. The study compared three planting dates (late October, late November, and late December) across two local landraces, Black and White seeded. Results clearly demonstrated that planting date was the most significant factor (p < 0.05) affecting all growth and yield metrics; differences between the two landrace were negligible. Sowing early in late October produced the most favorable results, yielding the tallest plants, the quickest time to flowering and maturity, and the highest yields (893.3 kg/ha for Black and 898.0 kg/ha for White sesame). Conversely, later plantings resulted in extended phonological durations, reduced seed weight, and dramatic yield declines of up to 50%. These outcomes are explained by crops facing diminishing soil moisture levels and exposure to suboptimal temperatures during the critical reproductive stages, which constrained flowering and seed filling. The distinctive contribution of the study lies in providing statistically validated, local evidence for an optimal sesame planting window. Our practical, climate-smart recommendation is to sow sesame by the end of October to maximize yields, build resilience to climate variability, and strengthen the crop’s economic success in marginal agro-ecosystems