Résumé
Context: Rural community land saturation and intensive livestock farming lead to new fodder demands no longer satisfied by the current systems. Livestock and crop farmers satisfy currently their fodder demand by growing maize which is rapidly expanding over traditional cereals resulting in a significant agricultural biodiversity decline. Breeding innovative novel double purpose sorghum varieties sorghum will help develop value chains around fodder production. This new fodder will bear a positive impact on farmers' incomes, particularly around urban centers where fodder shortages are a brake on intensive cattle farming. Material and Method: Sorghum varieties with improved fodder quality and higher biomass yield, integrating the bmr gene (better digestibility) were developed. Phenology and above ground biomass establishment were carried out to calibrate crop models to predict novel varieties adaptation. Feeding value was determined using near-infrared spectroscopy while productivity was confirmed through a multilocation trial network. Results and Discussion: Similar to landraces, new varieties, sensitive to photoperiod, adjust maturity according to the end of rainy season. Photoperiodic varieties are therefore naturally adapted to climate variability, which is the main expected effect of climate change. Biomass produced by new sorghum varieties exceeds that of maize. Using dwarf plants or late planting increases stover quality but also reduces biomass production while bmr trait introgression allows us to reduce stem lignin content without affecting yield potential. Many traits inherited from landraces (photoperiod, tillering, plant height and grain quality) that have long often been overlooked are now important stakes in breeding programs. Sorghum is known for its good water and mineral use efficiency, but crop models must be adapted to specific case of photoperiodic sorghums. Conclusion: This research, which reconciles science and local knowledge, will lead to the co-construction with farmers of new cropping systems compatible with an agro-ecological intensification fodder production.