AGRONOMIC BEHAVIOR OF ANNUAL RYEGRASS ( Lolium multiflorum LAM.) IN RIO GRANDE DO SUL STATE

The objective of this study was to evaluate forage production and number of days to flowering in 15 common ryegrass populations, one population of the KLM 138 (Uruguay) and Fepagro Sao Gabriel cultivars, and one local population in order to select germplasm with production potential. A randomized block design consisting of three replicates and repeated measures over time (cuts) was adopted. Forage production was evaluated by cutting samples of 2 linear meters per plot. The forage samples of each plot were dried and weighed for the determination of total dry matter. A total dry matter subsample of each plot, in each cut, was used to estimate leaf percentage. The data were submitted to analysis of variance using mixed models and means were compared by the Tukey test (P<0.05). A fourth replicate (block) using all populations was not submitted to cutting and was used to estimate the number of days to flowering. Flowering was defined when more than 50% of the plants of the plots had inflorescences. Except for the first cut, no difference in total dry matter production was observed (P>0.05), indicating little variability for this trait in the populations studied during the growth cycle. The populations differed significantly in terms of leaf dry matter percentage (P=0.0002). The highest leaf percentages during the growth cycle were observed for cultivar KLM 138. However, populations of the common Uruguayan, Dom Pedrito and Vacaria cultivars also exhibited good leaf production and may be used for initial selection of new promising materials, considering that a higher percentage of leaves promotes better quality feed offered to animals. The variation in the number of days to flowering permits selection for different maturation cycles of common ryegrass.