PERFORMANCE OF DIVERSE MAIZE GENOTYPES UNDER NITROGEN DEFICIENCY IN THE NORTHERN GUINEA SAVANNA OF NIGERIA

• Published in: Experimental agriculture Vol. 41; no. 2; pp. 199 - 212
• Main Authors: KAMARA, A. Y., MENKIR, A., AJALA, S. O., KUREH, I.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.04.2005
• Subjects: Adaptation to environment and cultivation conditions; Agricultural production; Agronomy. Soil science and plant productions; Biological and medical sciences; chlorophyll; corn; drought tolerance; flowering; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; genotype; grain yield; Land use; leaf area index; Nitrogen; nitrogen content; plant growth; savannas; selection criteria; soil nutrients; Soils; Varietal selection. Specialized plant breeding, plant breeding aims; Zea mays; Nigeria; West Africa; Sub-Saharan Africa; Africa; Guinea; Monocotyledones; Soil fertility; Cultivated soil; C4-Type; Inorganic element; Cereal crop; Tropical soil; Gramineae; Angiospermae; Agriculture; Intertropical zone; Adaptation; Zea mays; Nutrition; Savannah; Genetic resource; Deficiency; Nutrient recovery; Tropical crop; Tolerance; Genotype; Varietal selection; Nitrogen; Genetic improvement; Spermatophyta; Yield; Performance
• ISSN: 0014-4797; 1469-4441
• DOI: 10.1017/S0014479704002479

The Guinea savannas of Nigeria have a high potential for the production of maize because of favourable environmental conditions. Despite this high potential, the yields obtained in farmers' fields are still very low. This is due to soil degradation and nutrient depletion arising from intensification of land use. Nitrogen (N) is the major nutrient limiting maize production in the Guinea savannas where the use of inorganic fertilizers is low. One strategy for improving the productivity of maize is to select varieties that perform well under suboptimal soil N conditions. This study assessed the performance of diverse maize germplasm under a range of N levels. Growth and grain yields differed significantly between the genotypes at all N levels. These variations were more pronounced at zero and 30 kg N ha−1 than at 90 kg N ha−1. Grain yield under N-deficient conditions was correlated with an increased number of ears per plant, stay-green rating, leaf chlorophyll concentration, leaf area index, reduced anthesis–silking interval and reduced days to silking suggesting that these traits are linked to tolerance to N deficiency. One hybrid (Oba Super 2), the drought-tolerant genotypes and four maize genotypes previously selected for tolerance to N-deficient conditions performed better than the widely grown adapted controls under zero and 30 kg N ha−1. At zero N, the grain yield of maize decreased with advances in cycles of selection for tolerance to suboptimal N conditions suggesting that N deficiency in the selection environment was not sufficient to discriminate between genotypes. The good performance of drought-tolerant varieties under suboptimal N conditions suggests that selection for drought tolerance may confer tolerance to N-deficient conditions.