اثر رقابت درون گونه‏ای بر رشد علف‏هرز فرفیون ناجوربرگ

Wild poinsettia (Euphorbia heterophylla L.) is a summer annual weed, native to tropical and semi-tropical regions of America that is introduced to soybean fields in Golestan province in recent years and it has been problematic. To investigate density effect on wild poinsettia growth, a field experiment was conducted in a randomized complete block design with four replication at Ferdowsi university of Mashhad. Plant density levels included 6, 12, 24 and 48 plant/m2. Results indicated that intraspecific competition had significant effect on branching number, weight of leaf, stem and fruit per plant. Branching number and dry matter of various plant organs decreased with an increasing density. However, there is no significant difference between density of 6 and 12 plant/m2. Self-thinning was not observed in the high densities. But, growth of each plant reduced, so that inverse of plant weight was increased with increasing intraspecific competition. Total biomass and fruit per area were increased with increasing density. These results revealed that wild poinsettia plants had growth flexibility, and on a per-area basis, high-density populations were more productive.