Allelopathic effect of Parthenium hysterophorus L. on growth and productivity of Zea mays L. and its phytochemical screening.

Allelopathy concerns the effects of one plant on another due to chemical released by them or the breakdown of their metabolites. It is expected to be an important mechanism in the plant invasion process because the lack of co-evolved tolerance of resident vegetation to new chemical produced by the invader could allow these newly arrived species to dominant natural plant communities (Hierro and Callaway, 2003). Reduction in native plant biodiversity in natural and agro-ecosystems caused by alien invasive weeds are now being recognized as some of the world s major emerging problems. Such alarming threat are also being noticed in India. Parthenium is an annual herbaceous prolific weed belonging to Asteraceae family and has been accidentally introduced in India along with food grain PL-480. Parthenium weed not only competes with desirable crop and pasture species but also reported as a health ISSN: 2319-7706 Volume 3 Number 7 (2014) pp. 837-846 http://www.ijcmas.com