ALLELOPATHIC EFFECTS OF PARTHENIUM WEED ON GERMINATION, GROWTH AND DEVELOPMENT OF FIELD CROPS

Aqueous extracts of shoot included branch and leaves of Parthenium hysterophorus L. at 5, 3.75, 2.5 and 0 (w/v) concentrations were applied to evaluate their allelopathic on seed germination and seedling growth of four field crops namely, rice, wheat, chickpea and mustard under laboratory condition at Agronomy Seed Lab, Bangladesh Agricultural University (BAU), Mymensingh during the month of February to April 2020. The differences in response among the field crops, the effects of different concentration of the extract were noted. Average Percent Inhibition (API) (% reduction in seed germination + % reduction in shoot length + % reduction root length + % reduction in seedling dry weight)/4) in the test crops due to allelopathic effects of the weed was calculated. Results revealed that rice was mostly affected (API= 47.3) followed by chickpea (API= 35.7) and wheat (API= 26.3) while it was marked lowest (API= 22.5) in mustard due to allelopathic effects of Parthenium extracts. Seed germination was reduced by 59.2%, 34.9%, 36.7%, 35.3%, dry matter was reduced by 42.5%, 14.8%, 17.9%, 44.5%, shoot length was reduced by 48.4%, 20.1%, 55.2%, 4.2% and root length was reduced by 39.2%, 35.4%, 33.2%, 6.1% in rice, wheat, chickpea and mustard, respectively. The inhibitory effects of Parthenium extracts were increased progressively with the increase in extract concentration. A 5% extract of Parthenium weed is enough to reduce the growth of field crops by about 50%.