Study on the effect of Russian knapweed (Acroptilon repens) aqueous extract on seed germination and growth characteristics of purslane, common yellow mallow and wheat

In order to evaluate the effect of the Russian knapweed (Acroptilon repens) aqueous extract as a biological herbicide on the germination of weeds of purslane (Portulacaoleracea), common yellow mallow (Abutilon theophrasti), and wheat (Triticum aestivum), a factorial experiment (with a completely randomized design and four replicates) was conducted in 2016 in the laboratory and greenhouse of the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran. The experimental factors included plant types (purslane, common yellow mallow, and wheat) and concentrations of the Russian knapweed aqueous extract at 6 levels (0 (control), 5, 5.7, 10, 15, and 20%). The results showed that germination percentage, coleoptile length, radicle length, and total weight of the seedlings were significantly affected by different concentrations of the Russian knapweed aqueous extract, plant species, and their interactions. Russian knapweed aqueous extract had the least and the greatest inhibitory effect on the germination of common yellow mallow and purslane, respectively. It was observed that the reduction of the length of coleoptile under the effect of aqueous extract concentrations of Russian knapweed for all species was significant and with increase in concentration of aqueous extract of Russian knapweed to the fast slope decreased length of the coleoptile. In the case of the radicle length, the results showed that at concentration of 20% extract of Russian knapweed, the highest and lowest radicle length reduction was related to the common yellow mallow and wheat with amount of 99 and 21% compared to control treatments. Based on the test results, reduce of the dry weight of seedlings on 15 and 20% for concentrations of aqueous extract of Russian knapweed was observed for each of the three plants. The applied results of this research was includes the usability of Russian knapweed aqueous extract on concentrations of 15 and 20% and its impact on seed germination and growth of purslane and common yellow mallow weeds.