Experiment was carried out to study the suppressive effect of some grasses on the growth and development of parthenium (Parthenium hysterophorus L.). The experiment was consisted of three grasses (Cenchrus ciliaris L., Pennisetum perpureum, Panicum maximum Jacq) with their four mixture of sowing which was arranged in replacement series. From this experiment the effect of different grasses mixture significantly suppress the plant height, leaf number, and branch number, fresh and dry weight of as compared to parthenium grown alone. The tallest (76.67 cm) parthenium was recorded from 100: 0 (parthenium: grasses) whereas the shortest was recorded from Panicum maximum Jacq: Parthenium hysterophorus L. (7.67cm) followed by Cenchrus ciliaris L.: Parthenium hysterophorus L. (12.0cm) and Pennisetum perpureum: parthenium (13.0cm) at 25:75 (parthenium: grasses) mixture however no significance difference was observed among them. Similarly, these treatments also significantly reduced leaf number, branch number, fresh and dry weight of parthenium. Moreover, the relative crowding coefficients suggested that Panicum maxicum Jacq was more dominant than parthenium in plant mixture of 75:25 (Panicum: Parthenium). In this combination, P. maxicum Jacq had higher crowding coefficients (1.98). Aggressivity index also showed similar trends to that of relative crowding coefficients. In all seeding proportions, grasses (Panicum maxicum Jacq C. ciliaris and Pennisetum perpureum) were all determined to be useful at out compete and displacing parthenium weed and were found to be generally more dominant. Therefore Sowing of such pasture plants in infested areas can suppress the growth of parthenium weed and provide improved fodder for stock.
Keywords: Parthenium hysterophorus. L., competitive index, Grasses Suppression and management option