Genetic and crop-physiological basis of nitrogen efficiency in tropical maize [Elektronische Ressource] : field studies / von Mosisa Worku

Genetic and Crop-Physiological Basis of Nitrogen Efficiency in Tropical Maize: Field Studies von der Naturwissenschaftlichen Fakultät der Universität Hannover zur Erlangung des akademischen Grades eines Doktors der Gartenbauwissenschaften - Dr. rer. hort. - genehmigte Dissertation von Mosisa Worku (MSc) geboren am 28.06.1962 in West Shoa, Oromia, Äthiopien 2005 Referent: Prof. Dr. Walter J. Horst, Uni. Hannover Korreferent: Prof. Dr. Heiko C. Becker, Uni. Göttingen Tag der Promotion: 11. May 2005 Dedicated to the Children of the Horn of Africa who vanished because of famine GENERAL ABSTRACT Low nitrogen (N) stress is among the major abiotic stresses causing yield reductions in maize grown in the tropics. To alleviate the problem CIMMYT has identified maize cultivars with improved performance under low-N conditions. However, no information is available on the underlying mechanisms. The objectives of the present field studies were: (1) to estimate the magnitude of gene effects and combining ability under contrasting N environments, (2) to study the crop-physiological basis of N efficiency under field conditions, and (3) to study protein quality and quantity under a range of N levels.