Advances in Maize Breeding through the Cumulative Complex Improvement of Sources

Maize breeding, on which the future of maize production is based, can be expected to undergo further important developments in the 21st century. Opportunities for development are latent in a more scientific approach to production methods and in the better exploitation of the available genetic resources. There is no lack of favourable gene combinations contributing to higher yield (e.g. 20–22 t/ha). However, the genes and gene combinations controlling the improvement and stabilisation of performance are unfortunately scattered over various different races, varieties and individual plants, where they occur at low frequency. Combination breeding and, more recently, cumulative source management are designed to collect these genes and concentrate them in special parental lines and heterosis sources.