Brachiaria ruziziensis

Brachiaria ruziziensis or Congo grass is a forage crop that is grown throughout the humid tropics. With fast growth at the beginning of the wet season due to strong seedling vigour, ease of establishment, good seed production and yield and the ability to suppress weeds it has the ability to become developed into the most important forage crop planted in the tropics. With the aid of genomic tools to research the genotype and gain more information there is the ability to increase breeding programs which are currently rather limited. Brachiaria ruziziensis belongs to the Poaceae family, Panicoideae subfamily and the Paniceae tribe. A tufted grass, Congo grass is a creeping perennial that has short rhizomes which form a dense leafy cover over the ground. Stems of the plant arise from many-noded creeping shoots and short rhizomes and then when fully grown reach a height of 1.5 m when flowering. The leaves of this grass are soft but hairy, with an average width of 15mm, length of 25mm and a seed weight of 250,000/kg. The seeds should be drilled into a well prepared seed bed, sowing in rows that are spaced 60 cm apart and it can be grazed upon as soon as it is ready. Brachiaria ruziziensis has numerous common names that it is known by throughout the world which include Congo grass, Congo signal, Congo signal grass, Chinese cabbage, Kennedy ruzi, Kennedy ruzigrass, prostrate signal grass, ruzi, ruzigrass, ruzi grass; Spanish: Congo, Congo señal, gambutera, Kenia, pasto Congo, pasto ruzi, ruzi; Portuguese: ruzisiensis, capim Congo; French: herbe à Bengali; Thai: ya ruzi. Native to Burundi, Rwanda and Eastern Congo, where it derives its common name, this forage crop has now been naturalised throughout the humid tropics with four Brachiaria species now covering as much as 85% of the cultivated pastures of Brazil. Congo grass can be established from seed which is inexpensive although it needs to be stored for six months after harvest. Alternatively the grass can be established vegetatively from stem cuttings with root nodes. It requires light soils with moderately to high fertility though it does not tolerate strongly acidic conditions and performs best in a well-drained soil. It requires a reasonably high rainfall, though it can endure dry spells, with 1000 mm or more being preferable. It requires a well prepared seed bed but light disc harrowing gives good results. Although it responds well to light, with light intensity increasing yields, it can also be planted for grazing under coconut plantations. Optimum growth occurs at 33/28 °C day/night with a minimum temperature of 19 °C. Congo grass does have certain stress tolerances that are disadvantages to poor farmers and breeding these out in the future would add significant value to this crop. It demands a relatively high fertility soil for good growth as well as adequate fertiliser use if there is persistent grazing or cutting of the crop. Heavy frosts will kill this crop and a light frost will make future regrowth very slow. Congo grass flourishes well in a well drain soil and has a poor tolerance to floods and heavy rains. Although it is able to form a dense ground cover to compete with weeds, Congo Grass is susceptible to certain pests and diseases. It is severely attacked by the spittlebug who cause significant damage to the plant in Tropical America affecting the development and persistence of the plants. As well the plant seeds are known to be affected by the fungus Sphacelia in the Congo. Currently the only cultivar is the Kennedy Ruzi which can be found in both Thailand and Australia. It performs well on the wet tropical coast and has a high seed yield. Very little breeding has occurred current, but research into microsatellite markers could lead to further developments in genetic stocks and diversification of the crop.