Scientific papers

Urochloa (syn.—Brachiaria s.s.) is one of the most important tropical forages that transformed livestock industries in Australia and South America. Farmers in Africa are increasingly interested in growing Urochloa to support the burgeoning livestock business, but the lack of cultivars adapted to African environments has been a major challenge. Therefore, this study examines genetic diversity of Tanzanian Urochloa accessions to provide essential information for establishing a Urochloa breeding program in Africa. A total of 36 historical Urochloa accessions initially collected from Tanzania in 1985 were analyzed for genetic variation using 24 SSR markers along with six South American commercial cultivars. These markers detected 407 alleles in the 36 Tanzania accessions and 6 commercial cultivars. Markers were highly informative with an average polymorphic information content of 0.79. The analysis of molecular variance revealed high genetic variation within individual accessions in a species (92%), fixation index of 0.05 and gene flow estimate of 4.77 showed a low genetic differentiation and a high level of gene flow among populations. An unweighted neighbor-joining tree grouped the 36 accessions and six commercial cultivars into three main clusters. The clustering of test accessions did not follow geographical origin. Similarly, population structure analysis grouped the 42 tested genotypes into three major gene pools. The results showed the Urochloa brizantha (A. Rich.) Stapf population has the highest genetic diversity (I = 0.94) with high utility in the Urochloa breeding and conservation program. As the Urochloa accessions analyzed in this study represented only 3 of 31 regions of Tanzania, further collection and characterization of materials from wide geographical areas are necessary to comprehend the whole Urochloa diversity in Tanzania.

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.

Brachiaria grass is an important tropical forage of African origin. It produces high amount of palatable and nutritious biomass, tolerates abiotic and biotic stresses, improves soil fertility, increases livestock productivity, and reduces adversities of climate change. Since 2007, several improved Brachiaria grass cultivars (Brachiaria brizantha cvs. Marandú, MG4, Piatã, and Xaraés; B. decumbens cv. Basilisk; B. humidicola cvs. Humidicola and Llanero; Brachiaria hybrid cvs. Mulato, Mulato II, and Cayman; and other hybrid lines Bro2/0465, Bro2/1452, and Bro2/1485) have been introduced and evaluated in Rwanda for adaptation, biomass yields, animal nutrition, livestock productivity, and environmental qualities. Both on-farm and on-station evaluations of 13 improved Brachiaria grass cultivars and 2 checks – local Brachiaria grass and buffel grass at two different agroecological zones of Rwanda showed superior adaptation, higher biomass yields, and higher nutritive values of all Brachiaria grass cultivars compared to buffel grass. Subsequent study evaluating the impact of cutting regimes on agronomic and nutritional characteristics of improved Brachiaria cultivars and Napier grass showed forages harvested at 90 days after planting with high crude protein content (between 137 and 167 g/kg DM for Mulato II and Piatã, respectively) and high metabolizable energy (up to 9 MJ/kg DM for Piatã). These attributes have shown to increase animal production optimizing retention time of the particle phase of digesta in dairy cows which was shorter for Piatã (62.8 h) than Napier grass (83.1 h). Piatã had higher voluntary dry matter intake than Napier grass hence increased milk yield up to 50%. Furthermore, heifer fed on Mulato II had up to 54.7% more body weight and less enteric methane (14%) than heifers fed on Napier grass. These studies have shown Brachiaria grass as the most productive forage of high farmer preference due to its adaptation in low rainfall and acidic soils and the production of green foliage year-round. Therefore, improved Brachiaria grass has been promoted in 20 of 30 districts of Rwanda through various livestock development initiatives benefitting more than 4,800 farmers from South, Eastern, and Northern Provinces of Rwanda. In this chapter, we also discussed the prospects of Brachiaria grass in supporting the growing livestock sector in Rwanda and emerging challenges.

Brachiaria grass is a “climate smart” forage that produces high amount of palatable and nutritious biomass for livestock and performs well in infertile soils, sequesters carbon in soil, and provides several environmental benefits.

The objective of the study was to validate the productivity of Brachiaria grass and upscale the suitable cultivars for improved livestock feed resources in Kenya. We assume integrating Brachiaria grass into mixed crop-livestock system will enhance feed availability and livestock productivity, leading to increased food and nutrition security. Farmer participatory approach was adopted to evaluate and promote four Brachiaria grass (Brachiaria decumbens cv. Basilisk, B. brizantha cvs. Xaraes, Piata, and MG-4) in the Central Highland and Eastern Midland of
Kenya. The extension/advisory approaches used to promote Brachiaria grass cultivars included field days, village knowledge centres, agricultural shows, posters, and linkages with other institutions through multi-actor platform established under the InnovAfrica project. Generally, Brachiaria grass cultivars were more productive than the control (Rhodes grass) in most harvests reaching peak of 5.1–7.7 t/ha in the fifth harvest. For Rhodes grass, DM was less than 4 t/ha in all harvest and died by sixth harvest. Similarly, based on farmers’ evaluation using phenotypic traits, the Brachiaria grass cultivars had higher score than Rhodes grass except cv. Piata. The mean score ranged from 2.75 to
3.19 for Brachiaria cultivars, while for Rhodes the mean score was 2.63. Within 2 years of intervention, over 4000 farmers in the 2 project sites and additional 1500 farmers from other parts of the country have planted the Brachiaria grass. The demand for Brachiaria grass seeds is increasing due to benefits gained, e.g., increased milk production from dairy cattle fed on the grass. Our study will quantify the associated benefits from cultivation of Brachiaria grass with respect to a set of ecological, food and nutrition security, and social-economic indicators.

Legume-based cropping system and Brachiaria forage system could play a significant role in enhancing food and nutrition security and sustainable intensifications of African agriculture. To reveal this potential, a comprehensive review of literatures and assessment was performed using key indicators in relation to food and nutrition quality, agro-ecological services and socioeconomic benefits. The key indicators for legumes intercropping systems include: Grain yield, soil organic matter, food availability, nutritive values of legumes, maize and millets- based foods, proportion of income from crop sale and percentage of farmers aware and/or adopting intercropping. In the case of Brachiaria system, the forage biomass, milk yield, availability of milk, milk nutrition contents, income from Brachiaria grass and milk sale and people practising the Brachiaria technology were considered key indicators. Both systems showed positive impacts and contribute to a range of the United Nation’s sustainable development goals including 1, 2, 3, 12, 13 and 15 and other associated targets. Integrating legume-based cropping systems and Brachiaria forage system will enhance contributions of smallholder farmers to food and nutrition security. The necessary changes needed in technology, institutions and policies to upscale legume-based cropping systems and Brachiaria forage system were suggested. These changes include improved varieties, quality seeds, improved cultivation practices, market provision, effective extension and advisory services and support to the seed productions and distribution systems, among others. Yet, to fully tap the potentials of legume-based and Brachiaria forage systems sustainably and raise the profile of these climate smart systems, context specific research measures are necessary.

Brachiaria (syn. Urochloa) is one of the most important tropical forages grass of African origin. Its performance is affected by different constraints, including diseases. This study assessed the distribution, incidence and severity of Brachiaria diseases and documented farmers’ knowledge on Brachiaria diseases in Rwanda. Surveys were conducted in five districts in the dry and wet seasons of 2018 and 2019. Fungi associated with major diseases were isolated and identified based on internal transcribed spacer sequences. The demographic information and farmers’ knowledge of Brachiaria diseases and yield loss were collected using structured questionnaire. Surveys revealed widespread distribution of leaf blight, leaf rust and leaf spot diseases in Rwanda. Incidence and severity of these diseases differed significantly by districts, seasons and district × season interactions; the exception was the non-significant effect of season and district × season interactions on rust incidence in 2018. Molecular identification revealed Phakopsora apoda as a provisional leaf rust pathogen, and frequent association of fungi Epicoccum spp. and Nigrospora spp. with leaf blight, and Bipolaris secalis and Fusarium spp. with leaf spot symptoms. This study provides baseline information for future studies on Brachiaria diseases and recognises diseases as a major challenge to sustainable production of Brachiaria grass in Rwanda and East Africa.