Autotoxic effects of pearl millet aqueous extracts on seed germination and seedling growth

The root and shoot aqueous extracts of pearl miller cv. MH 179 were assayed at 20, 40, 60 and 80 g.1(-1) (dry weight basis) for their effects on seed germination and early seedling growth of pearl miller (Pennisetum glaucum (L.) R. Br.). Rate of germination declined with the increase in concentration of both root and shoot extracts while ultimate germination, root length, shoot length and total dry matter were at a maximum at 20 g.1(-1) concentration and then decreased with further increase in concentrations of both extracts, indicating concentration rate dependency. All concentrations of extracts increased the mean period of ultimate germination compared to the control. The highest concentration assayed (80 g.1(-1)) resulted in 60% and 40% decline in seed germination with root and shoot extracts, respectively, compared to control. The results of the study suggest that root and shoot of pearl miller contain water soluble compounds which are autotoxic. (C) 1996 Academic Press Limited