Seleção de populações de Bromus auleticus, uma gramínea perene de inverno

The objective of this work was to select the best bromegrass populations (Bromus auleticus) by analyzing their agronomic performance and morphological characteristics linked to persistence. Eight populations originated from four different municipalities from the state of Rio Grande do Sul (Santana do Livramento: A5, A6, A23 and A26; Uruguaiana: A7, A8; Julio de Castilhos: A17; Quarai: A27) were cultivated on 5-m rows containing from 12 to 15 plants. The plants were transplanted on 06/16/2004, and evaluations started 125 days transplantation. The plants were evaluated in relation to growth habit, seed and dry matter (DM) production and chemical composition during the years of 2004-2005. Due to the winter growth habit of this species, it was not possible to evaluate the DM production on the first year. During the fall-winter period of the second year, the plants were submitted to five cuts, with intervals from 31 to 47 days. Inter-population variability was observed and related to growth habit (semi-decumbent to tall), number of panicles (9 to 200/row), circumference (29.3 to 36.5 cm/plant), DM production (0.6 to 77.2 g/row) and weight of 1000 seeds (4.7 to 6.6 g), mean DM production per cut (137 to 421 g/row), total DM production (686 to 2105 g/row), crude protein (14.3 to 21.8%), acid detergent fiber (21.0 to 28.3%), neutral detergent fiber (53.4 to 58.8%) and hemicellulose (25.5 to 33.25). Populations A5, A23 and A26, due to their better agronomic performance, and population A8 due to the presence of rhizomes, are indicated for further evaluations in the species improvement program.