Proceedings of the International workshop on cocoa breeding for improved production systems, 19th-21th October 2003, Accra, Ghana

This is the fourth International Workshop to be organised by INGENIC, the International Group for the Genetic Improvement of Cocoa. The theme of the current workshop is of great importance, because average productivity of cocoa is still very low and progress in improving efficiency of production is more limited than in other tree crops, such as apples and pears. Low yielding varieties may be so because of low yield efficiency or because of poor adaptation to the environment. Low yields are sometimes obtained even under highly favourable growing conditions, which is an apparent paradox. Cocoa breeding to date might have overemphasised vegetative growth, which is important for rapid establishment of young trees, but which may be a disadvantage for adult plantations due to strong interplant competition and difficult management of the crop. Yield decline with age of the plantation is a common phenomenon. The continuous spread of devastating pathogens and pests also implies the need for lower cocoa canopies, which can be more easily managed. These important challenges need to be faced by breeders and agronomists in order to assist cocoa farmers. These issues were translated into the following questions that were dealt with in the workshop sessions: - How to select superior mother trees in heterogeneous progenies for more productive clone or hybrid varieties? - What are the factors affecting yield x vigour relationships in cocoa? - What are the needs and possibilities of developing more compact cocoa varieties? - What do we know about genotype by environment interactions in cocoa, including the effect of high density olantina on lona-term cocoa yield? (Résumé d'auteur)