[Evaluation of adaptation of Brachiaria accessions in eastern Brazilian Amazonia]

English. Forty-two new accessions of the forage grass Brachiaria spp. were evaluated at Paragominas (3 degrees 05' S, 47 degrees 21' O) in eastern Brazilian Amazonia together with four commercial accessions of this genus. There were marked intra and interspecific differences among accessions based on their degree of adaptation- an integrated measure of recovery to simulated herbivory, soil cover, potential for dry matter production and susceptibility to diseases and insects. A cluster analysis divided the 46 accessions into three distinct hierarchical groups with respectively, excellent, good and poor degree of agronomic adaptation. The accessions with best performance, which are recommended for further agronomic evaluation, were: B. brizantha BRA 003441, 003891, 004219 and 004308 and B. decumbens BRA 004391.

Spanish; Castilian. En un Oxisol de Paragominas, Para, Brasil, se evaluo durante 30 meses la adaptacion de 46 accesiones de Brachiaria (22 de B. brizantha, 12 de B. decumbens, 7 de B. humidicola, 4 de B. ruziziensis y 1 de B. dictyoneura). En tres periodos lluviosos y dos de sequia, se realizaron nueve evaluaciones en las cuales se midieron, en una escala de 0 (adaptacion) a 5 (excelente), la capacidad de rebrote, el vigor de crecimiento, la cobertura del suelo y la tolerancia a plagas y enfermedades de cada una de las accesiones. Para el analisis de los resultados se empleo el metodo de agrupamiento ("Cluster analysis"), resultando tres grupos definidos (excelente, buena y pobre adaptacion). Las accesiones con mejor desempeno fueron B. brizantha BRA 003441, 003891, 004219 y 004308 y B. decumbens BRA 004391.