Phytotoxic effects of "Euphorbia dracunculoides": a weed of rainfed chickpea-chickpea cropping system

Phytotoxic effect occurs when plants release chemicals that inhibit neighoubouring plants. Phytotoxic effects of aqueous extracts of different parts of Euphorbia dracunculoides L.  (green spurge) at two concentrations, and its infested soil were investigated on germination and seedling growth of chickpea (Cicer arietinum L.). The fruit extract at 1:20 (w/v) concentration caused maximum reduction (12%) in  germination of chickpea seeds while leaf extract at 1:10 (w/v) concentration resulted in maximum mean germination time value and minimum germination index of chickpea seeds. All the traits of chickpea seedling growth including emergence were adversely affected by the aqueous extracts at both concentrations. Further, the inhibition of chickpea seedling growth was more pronounced with 1:10 (w/v) concentration whereas the lower concentration (1:20 w/v) showed stimulatory effect on shoot length, seedling vigor index and chlorophyll contents of chickpea seedlings. The leaf extract at 1:10 (w/v) concentration proved most harmful to seedling growth and chlorophyll contents (76% reduction) of chickpea. Soil beneath the E. dracunculoides plants significantly reduced emergence (23%), seedling vigor index (55%) and chlorophyll content (19%) of chickpea but a significant increase in N (6%), P (16%) and K (4%) contents of chickpea seedlings was recorded. Thus it can be concluded that E. dracunculoides contains compounds in its tissues which may cause phytotoxic effects on chickpea under field conditions.