Allelopathic effects of Knotweed (Polygonum avicular) on emergence and seedling growth of tomato and corn

In recent years, allelopathy has received special attention by scientists in integrated weed management (IWM). To study the effect of different amount of Knotweed residue on emergence and growth of tomato and corn seedlings, two experiments were conducted at Ferdowsi University of Mashhad. The type of design was completely randomized, with 5 and 4 replications for tomato and corn, respectively. The Knotweed residues (zero, 0.33, 0.67, 1 and 1.33 %(W/W) were added to the pot soil. Seedlings showed different response to different amount of Knotweed residues. Increasing residues increased the emergence percentage of tomato but decreased corn emergence. Increasing residues resulted in increasing 33.9% and 39.3% of leaf area in tomato and corn, respectively. Knotweed residues resulted in 36.5% and 46.7% increase in shoot dry matter of tomato and corn, respectively. Increasing dry matter resulted in increasing up to 67.2% and 54.5% root dry matter of tomato and corn, respectively. Different doses of Knotweed had stimulatory effect on emergence of tomato but had inhibiting effect on corn. Knotweed residues had stimulating effect on seedling growth of corn and tomato. Root dry matters of both species were more influenced by Knotweed residue than foliage.