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In order to determine the agronomic performance of six accessions belonging to four species from the Brachiaria genus, a study was conducted during a year (rainy and dry seasons). The plant height was measured; likewise, leafiness, vigor and cover, affectations by phytophagous insects and pathogen microorganisms, chlorosis and biomass yield, were estimated. Principal component analysis (PCA) and cluster analysis were applied to the results, through the statistical package SPSS version 11.5. The total variance was high (higher than 90 %) for both seasons, related to the measured and/or estimated variables. The variables with the highest variability were height, affectations by pathogenic microorganisms and yield; in addition to leafiness, cover and vigor. An integral analysis allows to conclude that the accessions Brachiaria decumbens and Brachiaria brizantha CIAT-16322 stood out during the evaluation, for coinciding in both seasons. Their insertion in the flow of varieties is recommended, in order to obtain a commercial variety to be used in animal husbandry systems, in zones with predominance of moderate-fertility soils. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the structural and floristic composition performance of 19 accessions of Urochloa brizantha, associated with Stylosanthes guianensis CIAT-184 on an acid soil, after three years of simulated grazing. The variables live shoots-dead shoots ratio and floristic composition were analyzed. The measurements were made in all the rotations during the experimental period. The substitution of dead shoots was favorable in most of the treatments; four accessions stood out (CIAT-16322, CIAT-26646, CIAT-16332 and CIAT-16335) in which, at the end of the period, the index of substitution of dead shoots was over two. From the accessions, 36,6% reached a percentage higher than 80% at the end of the experimental period; the accessions CIAT-16317, CIAT-16335 and CIAT-16332 were the ones with higher presence of the base pasture (> 90%). In all the associations the legume was represented in a low percentage (< 16%); while the weeds remained, in most cases, below 20%. In general, the evaluated U. brizantha accessions showed an acceptable persistence or stability in time, and CIAT-16322, CIAT-26646, CIAT-16332 and CIAT-16335 stood out. [ABSTRACT FROM AUTHOR]