ZEA MAYS L در رقابت با ذرت AMARANTHUS RETROFLEXUS L اثر تراكم و زمان سبز تاج خروس

Effect of density and time of emergence of redroot pigweed (Amaranthus retroflexus L.) in competition with corn (Zea mays L.)

In order to study yield and yield components of corn (Zea mays L.) in competition with redroot pigweed (Amaranthus retroflexus L.) an experiment was conducted at Seed and Plant lmprovement lnstitute (SPIl), Karaj, Iran during 2000. Field study was carried out based on RCBD with 3 replications to determine the influence of redroot pigweed densities (3, 5, 8 and 10 plant per m of row) and times of emergence (same time with corn, 2-3 and 4-5 leaf number of corn) on yield and yield components of corn. Results indicated that early emergence of pigweed caused a decrease in harvest Index (Hl), row number, grain number per row and grain yield. Results also revealed that different time of emergence did not show any significant differences in kernel weight. Corn yield loss was 30% in early emerged pigweed and decreased to 25 and 12 percent in 2nd and 3rd time of emergence, respectively. There was no significant differences in corn traits under different redroot pigweed densities.