Brachiaria grasses are the most widely planted forages in the tropics. Brachiaria
pastures during the rainy season occasionally face waterlogging conditions that
severely limit pasture productivity and animal performance. Waterlogging drastically
reduces oxygen diffusion into the soil causing hypoxia which is the main limitation that
reduces root aerobic respiration and the absorption of minerals and water. Tolerance
to waterlogging was evaluated in different Brachiaria grasses (Baruch, 1994; Dias-
Filho and Carvalho, 1999; Dias-Filho, 2001; Rao et al., 2005). Dias-Filho et al. (1999)
found that B. brizantha is intolerant, B. decumbens is moderately tolerant and B.
humidicola (Bh) is tolerant to waterlogging. But Bh is of low forage quality. An on-going
Brachiaria breeding program at CIAT is developing hybrids that combine the desirable
attributes including spittlebug resistance, Rhizoctonia resistance, adaptation to major
abiotic stress factors (acid soils, waterlogging, drought), forage quality and seed
production. Reliable screening methods are needed to evaluate the Brachiaria hybrids.
The main objective of this study is to establish a rapid and reliable selection
methodology to evaluate the tolerance of the Brachiaria genotypes for waterlogging
and to identify plant attributes that can be used as indicators of waterlogging
tolerance.