Azuche, Hymenachne amplexicaulis (Rudge) Nees, Forage Genetic Resources for Floodplains in Tropical Mexico

Azuche Hymenachne amplexicaulis (Rudge) Nees is a C₃ grass native to tropical flooded areas in South and Central America with 2n = 2x = 24 chromosomes. During 2002 and 2003, the Graduate College for Agricultural Sciences (CP) and the Mexican Institute for Forestry, Agriculture and Animal Production Research (INIFAP) organized an expedition to collect the genetic diversity of this species within tropical Mexico, in order to preserve and study it under nursery conditions. The collection was performed from Puerto Vallarta to Tapachula on the Pacific and from Palizada, Campeche to Veracruz on the Gulf of Mexico coast, and also crossing sections through the Tehuantepec isthmus and through the Sierra Madre de Chiapas. Ninety sites were sampled, on each, 25 tillers were collected, tagged and stored in a commercial soil mix until establishment of individual plants within 6 l pots. The largest Azuche prairie observed had a 10 ha surface, with the grass limited to small surfaces of up to 0.25 ha. It was not found on places with salty water, even seasonally. The Pacific coastal side is less abundant in niches for this species. Producers' experience indicated that this grass is beneficial for milk production compared with other forage grasses, mainly C₄, growing in flooded areas. Initial studies of genetic diversity showed wide morphological variation for sprouting ability, leaf width and length among samples. Azuche diversity showed good potential production attributes for farm and wild animals, under flooding tropical savanna conditions.