Homecoming of Brachiaria: Improved hybrids prove useful for African animal agriculture

Species of the genus Brachiaria originate primarily from Africa, where they are constituents of natural grasslands. Due to their adaptation to acidic, low-fertility soils, millions of hectares of Brachiaria species have been sown as improved pastures in South and Central America, especially B. brizantha cv. Marandu and B. decumbens cv. Basilisk. Due to B. decumbens' susceptibility to spittlebug insect pests in the Americas, CIAT in Colombia and EMBRAPA in Brazil initiated breeding programmes in the 1980s. First cultivars released from CIAT's breeding programme – cvs. Mulato and Mulato-II – have also been investigated in African countries. They have been examined for integration in conservation agriculture systems (Madagascar), for drought and acidic soil tolerance (Rwanda) and for intercropping forages in dairy systems (Uganda, Madagascar), among others. Seed sales to African countries suggest that an area of at least 1,000 ha has been sown so far. The largest adoption of cv. Mulato-II is currently happening in eastern Africa, where it is used by over 20,000 farmers as a trap plant in the push-pull system for control of maize stem borers and parasitic Striga weed. Cv. Mulato-II's particular advantage is its relatively high crude protein content due to greater leafiness and thinner stems than those of traditional Napier grass, resulting in higher nutritive quality. Yet new pest challenges have emerged, requiring further research attention. Diverse hybrids are in the pipeline for release, among them those that are suitable for cut-and-carry systems which are prevalent in eastern Africa. This paper reviews research, development and incipient adoption of new Brachiaria hybrids in African countries. (Résumé d'auteur

L’utilisation de la télédétection pour la classification des zones de pâturage de Tsiroanomandidy (Madagascar) via l'algorithme « Random Forest »

International audienceDemand in animal products rises over the world, because of the growth of population, urban planning, and the rise of income. Nevertheless, this situation causes major changes on land uses, tending to reduce the surface of pasture areas. Such event decreases the availability of forage resources and the movement of cattle herds which are basic factors for animal production in some countries of the world. Madagascar, as a developing country, follows this tendency, particularly for cattle sector which is the first source of animal protein of the population. The design of a system for monitoring forage resource availability at a regional level seem to be an interesting way whether forage reserves need to meet the cattle feed. Implementing this system requires a less complex, but more reliable and easily reproducible approach, that might be applied to large field surfaces. Thus, a grading of the various pasture areas of the region of Tsiroanomandidy was conducted using a combination of remote sensing technique and modelling. The former uses the reflecting property of objects from earth surface to convert them into exploitable data and recorded into images by a multispectre satellite. The use of « Random Forest » algorithm on data received from SPOT 5 satellite has led to results which were close to the reality. The grading of the five most common forage spieces on nature pasture lands of Madagascar has reached an overall accuracy of 77.6%. These figures were reported to the map to determine land uses of the region and served to calculate the capacity load of the region which was of 29 752 TLU/year. This map could be used as a decision tool to improve pasture management of a region. The study needs to be deepened particularly by increasing the number of monitored parcels and satellite images for the modelling