INFLUENCE OF THE BIOSTIMULANT FOLCYSTEINE ON THE INTERFERENCE OF PURPLE NUTSEDGE (CYPERUS ROTUNDUS L.) WITH EGGPLANT (SOLANUM MELONGENA L.)

摘要

Experiments were conducted to determine the effect of the biostimulant folcysteine on the interference relationship between eggplant (Solarium melongena L.) and purple nut-sedge (Cyperus rotundus L.). The influence of folcysteine on the competitive ability of eggplant and nutsedge was assessed with a replacement series study performed in the greenhouse at the University of Florida, Gainesville, and in Santo Domingo, Dominican Republic. The influence of folcysteine on the interference of nutsedge witheggplant yield was determined in an additive series field study with or without folcysteine, conducted in Santo Domingo, Dominican Republic. 'Jira Moradita' and nutsedge from Gainesville, Florida, and San Cristobal, Dominican Republic, were utilized forthe greenhouse and field studies, respectively. In every experiment, eggplant transplants (15 cm in height, 3-4 true-leaf stage) were sprayed with an aqueous solution of folcysteine (0, 100, 200, 300 or 400 ppm in the competitive ability study, 0 or 400ppm in the additive study) immediately before transplanting. Purple nutsedge was allowed to interfere with eggplant for 32 days (replacement series study) or season-long (additive series study). Results of the replacement series experiment indicate thatincreasing the folcysteine rate increased dry matter accumulation in eggplant, enhancing its competitive ability when interfering with purple nutsedge. Data from the field experiment indicate that increasing purple nutsedge density reduced eggplant yield, and that eggplant with or without folcysteine treatment attained the same extent of yield loss from purple nutsedge interference at a given weed density. The purple nutsedge density/eggplant yield loss relationship was best fitted to a rectangular hyperbola equation, with maximum yield loss values of 28% at the weed densities of 150-200 plants per m~2. Although folcysteine increased the early competitiveness of eggplants, that effect was not reflected in fruit yield. This finding indicated that the early eggplant growth stimulation by folcysteine did not sufficiently overcome the negative effect of season-long purple nutsedge interference. Future research should explore the effect of post-transplanting folcysteine treatments on the yield of purple nutsedge-infested eggplant.