ABSTRACT

The term functional genomics includes approaches to determine precisely the function of genes. Genetic mapping began very early in maize, with numerous mutations available. Apart from the fundamental interest, the information obtained on maize and wheat has important implications for breeding programmes. The search for physiological and agronomic bases of genetic variability of nitrogen use efficiency in wheat and maize is an example of the use of multifactorial genetics combined with integrated biological studies on the whole plant. The mobilization of nitrogen associated with plant senescence is a genetically determined process that develops naturally over the life of the plant and the evolution of which can be influenced significantly in favourable or unfavourable environmental conditions. Advances in the understanding of genes and their biological effects can have a major impact on plant improvement. Maize, wheat, and rice belong to the same family and share a common ancestor.