Centrosema brasilianum

Centrosema brasilianum is a prostrate-trailing to twining, perennial, herbaceous legume. Amongst different studies, some erect and semi-erect forms were identified along with adventitious roots on trailing stems. Leaves are trifoliate, leaflets elliptical-oblong, sometimes ovate, 3.3-6.6 cm long, 1.5-3.6 cm wide. Flower racemes consists of 2-5 flowers, or sometimes solitary. Bracteoles either are glabrous or pubescent, ranging from 3–13 mm long, 12–17 mm long and 5–10 mm wide, ovate and flat or cupped. Peduncles in the leaf axis vary from 4–30 mm long. The papilionate flower is generally violet, violet-blue or red-lilac, and in rare cases also purple or white. Outcrossing may cause a degree of variation in color intensity. From time of sowing to flowering varies between 3–7 months. Pods are linear, dehiscent, 70–160 mm long and 4–5 mm wide, containing roughly 8-23 seeds. Seeds vary from dark to light brown and can sometimes be grey, black or yellow, often with stripes or spotted with a cylindrical shape raging 3.4-4.4 mm long, 2.3-3.1 mm wide.[2][3][4][5][6]

Centrosema brasilianum was listed as one of the species under Clitoria which are currently accepted as Centrosema, but these species were known to Plukenet (1691). George Bentham (1837) listed 25 species of Centrosema and by 1859 listed another 18 species and then reduced 20 of these to synonyms; establishing C. brasilianum (L.) Benth. as one.[11]

Centrosema brasilianum forage quality is high and compares favorable with other tropical legumes. Reports of a range of 11.8%-19.6% of crude protein were found in large collections evaluated in Colombia and Nigeria during sampling at ages of 6–18 weeks, respectively.[15][16] Reports on in vitro dry matter digestibility range from 28-56%.[17] In contrast to many other tropical legumes, C. brasilianum maintains its quality and retains its leaves under drought to a large extent which is an important characteristic when searching for forages for dry environments.[18][19][20][21] Centrosema brasilianum is highly palatable.[22][23]

Establishment and germination of C. brasilianum is generally good. Report indicated that after evaluation of 257- seed accessions, a 40% success rate was established in field germination and 84% in the laboratory.[24] Prior to sowing, scarification is a necessity along with hot water treatment, Osram irradiation and sulphuric acid.[25] Centrosema brasilianum establishes relatively slowly, therefore weed control during establishment is advantageous. Once established, it competes well in grasslands with sowing depths of only 5 cm and seeding rates of 4–5 kg/ha.[26][27]

While C. pubescens has been the most commercialized legume of the genus Centrosema, other species have shown good potential. Studies are probably not necessary on stratification methods since much can be extrapolated from existing experience and current methods of management. With weeds being a major problem at establishment, research is required to identify effective and low cost weed control programs along with fertilizer requirements. The greatest gap to overcome is providing a framework for developing a strategy of grazing management that is applicable to a wide range of climatic and edaphic conditions.[28]