Assessment of Allelopathic Effect of Pale Persicaria on Two Soybean Cultivars*

The experiment was conducted to assess allelopathic potential of water extracts from weed species pale persicaria (Polygonum lapathifolium L.) on germination and initial growth of two soybean cultivars (Ika and Sanda). Water extracts from dry stems and leaves of P. lapathifolium in concentrations of 1, 5 and 10% were examined under laboratory conditions using Petri dishes. Results showed that soybean cultivars differed both in their response and sensitivity to allelopathic effect of pale persicaria extracts. Overall, cultivar Ika was more susceptible than cultivar Sanda. On average, germination of soybean was not significantly affected by extracts. The highest germination reduction was recorded with 5% leaf extract for 10.1%. However, Sanda germination was slightly more affected. Contrary, extracts showed greater effect, both stimulatory and inhibitory, on root and shoot length and fresh weight of Ika. Both stem and leaf extracts in 10% concentration had the highest inhibitory effect, up to 48.8%. The increase in extract concentration exhibited higher inhibitory effect, while the lowest concentration generally stimulated soybean growth.