Morphogenetic characteristics of "Canarana" (Echinochloa pyramidalis Lam.) at different ages of regrowth.
The morphogenetic and structural characteristics of Canarana-Erect-Lisa (Echinochloa pyramidalis Lam.), harvested at 10; 17; 24; 31; 38 and 45 days of age, were evaluated. The morphogenetic evaluations included leaf appearance, elongation and senescence rates, besides the phyllochron. The structural measurements were: number of expanded live leaves and number of aerial tillers. A complete randomized block design, with three replications, were adopted. Fertilization or soil correction were not accomplished. Lineal and positive answer was observed among degree-day accumulation (GD) and Haun index, being considered phyllochron of 115 GD for the basal tiller. Leaf appearance rate linearly decreased with age harvest according the equation Ycircumflex˜=0.3235-0.001758**ID (R2=0.82), varying from 0.3 to 0.24 leaf/day for tiller at 10 and 45 days, respectively. The number of expanded live leaves tended to stabilize with 5.5 at 25th day of regrowth, period that the leaf senescence rate increased strongly. It is recommended for Canarana a regrowth interval of approximately 25 days, with the objective of to maximize the efficiency of use of the forage and to prevent larger losses relative to senescence and death of leaves.