Brachiaria species in north-east Thailand:: dry matter yields and seed production

Two field experiments were conducted during 2000-2002 in north-east Thailand to compare dry matter yields and seed production of Brachiaria ruziziensis (ruzi grass; common Thailand type), B. decumbens (common. signal grass) cv. Basilisk, B. decumbens (CIAT 26297), B. brizantha cv. Marandu (CIAT 6780) and B. brizantha (CIAT 6387). Marandu, Basilisk and CIAT 6387 produced 50%, 46% and 43%, respectively, more dry matter than ruzi grass over 3 dry seasons. In addition, during the research period, Marandu and CIAT 6387 produced in excess of 30% more leaf dry matter than ruzi grass. CIAT 26297 produced similar dry matter yields to ruzi grass but produced the highest leaf crude protein concentrations of all the trial cultivars. Basilisk produced the greatest number of inflorescences in 2001 followed by CIAT 6387 and ruzi grass, while in 2002, ruzi grass produced 76% and 150% more inflorescences, respectively, than Basilisk and CIAT 6387. Both Marandu and CIAT 26297 produced very few inflorescences in either year. Ruzi grass produced 30 and 80 kg/ha seed in the two years, while the other species produced negligible amounts of seed. The failure of Basilisk in particular to produce adequate quantities of good seed was attributed primarily to failure of either or both seed set and caryopsis maturation. The implications of this and other factors are discussed in relation to the importance of site selection for more successful seed production of Basilisk and other accessions of B. decumbens and B. brizantha in Thailand.