Responses of growth, yield and N use efficiency of selected tomato cultivars to variations in hydrothermal regimes of the cropping seasons in a tropical rainforest zone of Nigeria

This study evaluated responses of some cultivars of tomato to weather events of the cropping seasons in terms of growth, fruit yield, and nitrogen use efficiency when grown under the application of inorganic and organic manures. The tomato varieties selected for evaluation Ibadan local, SAMTOM and Roma VF elite lines, and were grown as both early and dry season crops in the humid rainforest zone of Nigeria. The cultivars were characterized by strong genotype by environment interactions and seasonal and/or genotype-specific N use efficiency. In both cropping seasons, the tomato cultivars differed in their ability to take up and accumulate N in the shoot and fruit tissues from the organic and mineral fertilizers. Significanty higher values of fresh and dry weights of root and shoot biomass were produced by tomato plants grown in plots in which NPK and poultry manure were applied over unmanured plots. Superior efficiencies of N uptake and utilization for fruit production were recorded for the Roma lines (T1410 and T1579). Delayed planting (dry season crop) did not considerably decrease N uptake and utilization efficiencies of N, but decreased final crop dry matter yields.