October 10th, 2017 / Claudia Canales – B4FA

Brachiaria grasses, which originated primarily from natural grasslands in Africa, do not look particularly remarkable. Yet these forage species for feeding farm animals are the most widely used in the tropics, especially in Central and South America, where they were introduced in the middle of last century in an effort to increase the profitability of the livestock sector by addressing shortages of feed. In Brazil alone, Brachiaria is now planted in over 99 million hectares (85% of the cultivated pastures of the country).

Because Brachiaria is adapted to acidic, low-fertility soils and is much more nutritious than the native forage species, the productivity of grazing animals is increased between 5-10 times, which effectively means more meat and milk. In monetary terms, Brachiaria pastures generate an additional yearly value of about US$1 billion in Central America, and these grasses are also credited to have revolutionised the Brazilian beef sector which generates revenues of US$50 billion and employs about 7.5 million Brazilians. Brazil is also the biggest exporter of Brachiaria seeds, supplying all Latin American countries. This is a lucrative business: about 8 million hectares of pastures need to be restored or replanted each year.

A climate-smart grass
Brachiaria grasses can also help to mitigate climate change because of their ability to inhibit nitrification, the process that results in the conversion of stable nitrogen in the soil to nitrous oxide (a greenhouse gas 300 times more potent than CO2) and to nitrate which is leached from the soil and pollutes water sources. In addition to benefiting the environment, the preservation of nitrogen in the soil also improves the growth of subsequent crops and saves on the costs of fertilisers.

Brachiaria starts the journey back home
Despite their enormous contribution to the livestock sector in Latin America, Bracharia grasses are only recently being introduced for commercial cultivation in African countries at a significant scale. So Brachiaria is slowly returning home, improved by several decades of plant breeding initiatives in Latin America to increase its nutritious qualities, hardiness and resistance to pests. A study by the International Centre for Research in Tropical Agriculture (CIAT) estimated that the potential benefits of growing Brachiaria for two million smallholder dairy farmers in Kenya, Tanzania, Ethiopia, Uganda, Rwanda and Burundi could be in the order of tens of millions of dollars, with positive knock-on effects for other stakeholders in the value chain. Other studies have showed similar results: milk production in cows reared in Brachiaria pastures could increase by up to 40% in Kenya and Rwanda compared to native grasslands; and benefits in the coastal areas of Kenya over 20 years would be in the order of US$17 million, with consumers benefitting from 30% of these.

Drought-tolerant Brachiaria is also currently being cultivated by more than 30,000 maize smallholder farmers in Kenya, Ethiopia, Tanzania, and Uganda as part of the companion crop or pull-push production system designed to control maize stem borer infestations, where it has replaced Napier grass as the “trap” crop for borers. It is a more nutritious feed for cattle than Napier grass too.

The road ahead
Despite the huge success of Brachiaria, the fact that it reproduces mostly asexually (offspring come from one parent only) means that the level of genetic diversity is low, and populations consist of clones that are genetically homogeneous. This means that production systems are very vulnerable because susceptibility to a new pest or disease could potentially wipe out millions of hectares of pastures at once. Since many Brachiaria grasses originated in Africa, one avenue of research is sampling plants from the wild  to increase the genetic diversity of collections used for plant improvement and conservation initiatives. Another set of initiatives aims to evaluate and select suitable varieties for the different ecological zones of African countries, and to establish the most appropriate farming practices to increase the performance and nutritional quality of the grass with the participation of farmers in the selection process. Crop improvement programmes will also have to address specific constraints to Brachiaria in Africa, such as pests and diseases, to develop improved resistance and determine suitable management practices. And last but not least, cultivars are also being evaluated for their potential for seed production.

Claudia Canales Holzeis is a plant molecular biologist with a near-decade of experience in plant genetics research.  She previously worked as Senior Project Officer for the International Service for the Acquisition of Agri-Biotech Applications (ISAAA), based in the Philippines.  A graduate of the University of Reading in Environmental Biology, Claudia Canales gained a DPhil. in Plant Genetics at Oxford.