| Popis: |
The moist savanna of West Africa has a great potential for maize production, but this is not often realised because the soils are particularly poor in available nitrogen. In two-year field experiments conducted on a Plinthic Luvisol in Zaria, northern Nigeria, agro-physiological traits of five tropical maize cultivars were assessed under four N levels (0, 0.56, 1.12 and 2.26 g plant −1). Application of 1.12 g plant −1 was optimum for maize production under the prevailing conditions. The most widely grown open-pollinated cultivar (TZB-SR) was the least efficient in utilizing available nitrogen for grain production especially under nitrogen stress because of its limited sink capacity (small harvest index and kernel size) and a slow kernel growth rate. But it ranked among the highest in whole shoot biomass accumulation and in number of kernels per plant. Under nitrogen stress, silking was delayed in cultivars 87 TZPB-SR and TZB-SR by 5–7 days compared to the other cultivars. Cultivars SPL and EV8728-SR showed better synchronization of anthesis and silking (ASI ≤ 4.5 days) which indicates a better ability to adapt to nitrogen and moisture stresses than the other cultivars. Nitrogen-utilisation efficiency of the cultivars was the most important component of N efficiency and could be predicted from harvest index. |
