Resumo

VERA, A et al. Ecophysiological evaluation of intraspecific competition of Cenchrus ciliaris L. (Poaceae) in pots. Rev. Fac. Agron. [online]. 2006, vol.23, n.2, pp.151-160. ISSN 0378-7818.

Intraspecific competition of buffelgrass (Cenchrus ciliaris L.) planted in pots was evaluated using ecophysiological parameters and the competition coefficient. Experiments were carried out on the University of Zulia campus, adjacent to the Faculty of Sciences, under ecological conditions of a Very Dry Tropical Forest and irrigation. A method of additive density with 2, 4, 8 and 12 plants/pot was used, and a randomized block design with four replications was applied. After transplant, biomass of all plants was harvested twice at 15d and 30d. Plant height, leaf area, root dry weight, shoot dry weight, and total dry weight were significantly greater (P<0.01) in low density treatments (2 and 4 plants/pot) versus high density (8 and 12 plants/pot) treatments. Number of leaves was relatively greater at low plant densities, and flowering was present in the 30d harvest. The coefficient revealed limited competitive capacity for the 15d harvest, but for the second evaluation period, a more intense interaction was detected. Severe intraspecific competition was demonstrated as population density increased. The relation of the coefficients (A₁/A_o) helped collaborate this ecological interaction. We recommend further vegetative competition studies using other weed species of agroecological importance in the Maracaibo Plains, Zulia State, Venezuela.

Palavras-chave : buffelgrass; Cenchrus ciliaris; intraspecific competition; Maracaibo; Poaceae; Venezuela; weed.