BIOHERBICIDAL POTENTIAL OF PLANT EXTRACTS AGAINST WEEDS OF WHEAT CROP UNDER AGRO-CLIMATIC CONDITIONS OF PESHAWAR-PAKISTAN

The possible ill effects of herbicides usage in agriculture have increased the interest of farming and researchers community to explore new ways of weed control. Bioherbicides (Allelochemicals) are considered as an available option for weed management. In order to test the potential of some allelopathic plant water extracts as a weed management tool in wheat crop, a field trial was carried out during winter 2011-12 at NDF, The University of Agriculture Peshawar Pakistan. The experimental design was RCBD having split plot arrangement. The main plots assigned to time of treatment application (pre emergence and post emergence) of plant extracts, while there were eight sub plots consisting of different weed control measures i.e. sorghum water extract {Sorghum bicolor (L.) Moench}, sunflower extract (Helianthus annuus L.), Parthenium extract (Parthenium hysterophorus L.), common reed extract {Phragmites australis (Cav) Trin}, Johnson grass extract {Sorghum halepense (L.) Pers}, Rice straw extract (Oryza sativa L.), herbicide (Logran Extra) and control. The results demonstrated that the pre emergence application of all the plant water extracts proved to be superior in action to their post application regarding weed control. Among the plant water extracts (treatments) the pre emergence application of both P. australis and H. annuus gave the minimum weed density of 89.50 and 113.50 m^2 respectively compared to control plot (280.0 m^2). Tallest (113.9 cm) plant height and outmost grains spike^-1 (64) was computed for H. annuus. In addition, the P. australis and herbicide (Logran extra) both proved superior for 1000 grain weight, however the leaf area of wheat remained non-significant under all examined treatments. The present results suggest that P. australis and H. annuus could be successfully incorporated in weed management approaches in wheat. Currently allelopathy is passing through experimental stages. Thus, further comprehensive studies are suggested to explore the possibility and feasibility for commercializing the extracts of these two species.