effect of water extracts of salvia officinalis and artemisia sieberi on seed germination and seedling growth of amaranthus retroflexus

allelopathic plants, because of reduction in herbicide uses, are important in weed management. the allelopathic effects of sage salvia officinalis and white wormwood artemisia sieberi water extract were evaluated on germination and seedling growth of redroot pigweed amaranthus retroflexus at concentration of 0, 5, 10, 15, and 20% in controlled conditions. anova revealed that the extract concentration has significant effect on root and shoot length, root/shoot length, fresh and dry seedling weights. the significant interaction effect of extract source  concentration was seen on percentage, rate and index of germination. the maximum percent (62.50 %) and rate (10.40 % per day) of redroot pigweed germination were observed at control treatment and the minimum percent (10 %) and rate (1.70 % per day) of germination were obtained from 20 % of sage and white wormwood extracts, respectively. the highest germination index (1.40) was obtained from 5 % extract of white wormwood and the lowest value (0.40) from 20 % extracts of sage and white wormwood. the longest (4.59 and 0.17 cm) and shortest (1.63 and 0.12 cm) root and shoot, and the highest (28) and lowest (13.60) of root/shoot length, the maximum (2.78 and 0.39 g) and minimum (0.11 and 0.02 g) seedling fresh and dry weights were obtained from 0 and 20 % of extracts, respectively. sage and white wormwood extracts caused in reduction of seed germination and seedling growth of redroot pigweed. generally, the negative effect of sage extract was greater than white wormwood on studied traits