Résumé
Participatory plant breeding (PPB) has a considerable potential to maintain local biodiversity. With PPB, breeders and farmers share their knowledge and skills in order to develop varieties or breeding strategies together. Diagnostic methods used in PPB help to create a more effective dialogue between researchers and farmers. This enables scientists to better understand the local farming conditions, the farmers' traditional diversity management as well as their specific needs and preferences. Therefore, participatory breeding programs work with a wider range of diverse breeding materials. Furthermore, participatory plant breeding implies decentralised selection, i.e. farmers grow crops in their own fields and make local selection decisions themselves. In Rajasthan, India, a project was initiated by the International Crops Research Institute of the Semi-Arid Tropics (ICRISAT) and the University of Hohenheim, to form the basis for a breeding program that would involve farmers as research partners. The approach was based on: the understanding of farmers' concept of a variety, the analysis of farmers' management of pearl millet seed, and the utilisation of farmer-generated populations to develop locally acceptable and improved pearl millet germplasm. Farmers' seed management strategies and variety concepts were analysed using social science methods. The effects of farmers' seed management practices (introgression of modem varieties and selection) on the genetic structure of pearl millet populations were analysed by quantitative genetic methods. For this purpose samples of 33 farmers' seed stocks were collected in western Rajasthan and evaluated in field trials together with control cultivars. Results showed that farmers' variety concept is effective and farmers' seed management practices affects diversity, adaptation and productivity of pearl millet populations. A participatory plant breeding program in Rajasthan would thus allow making use of farmers' breeding interventions and farmers' knowledge to achieve together breeding aims and to safeguard the local pearl millet diversity. (Résumé d'auteur)