Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2004.279.286NasirZaheer AhmadSultanSikander 2200472A survey of mustard crop in District Chakwal was carried out during March, 2000 to determine the field uniformity, constancy, density, herbage coverage and importance values of weeds. A total of 42 weed species including 4 monocot were recorded. The species with 50-100% field uniformity were Asphodelus tenuifolius, Convolvulus arvensis, Fumaria indica and Medicago denticulata. While Anagallis arvensis, A. tenuifolius, C. arvensis, F. indica, M. denticulata, Sorghum halepense and Trifolium polycerata had high density than other species in the area. Species with better herbage coverage were Artemisia scoparia, A. tenuifolius, C. arvensis, F. indica, M. denticulata, S. halepense and T. polycerata. Most of the weed species fell in constancy class I (64.29%). In terms of importance value, A. tenuifolius, C. arvensis, Vicia monantha, S. halepense and T. polycerata were top ranking and most prevalent weeds associated with mustard crop. Although there is floristic heterogenity in the weed flora of the area but some weeds (A. tenuifolius, C. arvensis, M. denticulata, Carthamus oxycantha) had distribution through out the district. The prevalence of these weeds must be arrested to improve the mustard production.]]>Khan, R.U. and A. Rashid,1989215Aslam, M., M.S. Mirza, A. Ghafoor, M.R. Chatha and A.R. Khan,198991216Al-Yemeny, M.N.,19992713Roth, C.M., J.P. Shroyer and G.M. Paulsen,2000sorghum on wheat under several tillage systems.]]>92855860Rifai, M.N., M. Lacko-Bartosova and P. Brunclik,20003933938Thomas, A.G.,1985333443Kevin, V., M. McCully, G. Sampson and A. Watson,1991Vaccinium angustifolium) field.]]>39180185Frick, B. and A.G. Thomas,19927213371347Bokhari, M.H., A.A. Dasti and S. Ahmed,198632289303Colbach, N., Nathalie, F. Forcella and G.A. Johnson,200048366377Hussain, F., M.Z. Qureshi and S. Shaukat,198810273278Vangessel, M.J., E.E. Schweizer, K.A. Garrett and P. Westra,1995Zea mays) yield.]]>43215218Hallgren, E., M.W. Palmer and P. Milberg,19998710371051Tamado, T. and P. Milberg,2000Parthenium hysterophorus L.]]>40507521Nizami, M.I.,198922933Buhler, D.D., K.A. Kohler and R.L. Thompson,200115170176Murad, A., F. Hussain, Q. Marwat and Z. Mohammad,19951153165Khalid, S.,19881273278Khan, D., M. Faheemuddin, S.S. Shaukat and M.M. Alam,2000Lasiurus scindicus Henr and Cenchrus setigerus Vahl dominated by dry sandy desert site of Karachi.]]>32171210Marwat, K.B., G.R. Marwat and F.M. Sarim,19936115Siddiqui, S.U., S. Khalid, R.A. Shad and K.B. Marwat,1993Orobanche aegyptiaca and O. cernua: Two important parasitic weeds of crops in Pakistan.]]>66167Malik, Z.H. and F. Hussain,1990614Buhler, D.D., R.G. Hartzler, F. Forcella and J.L. Gunsolulus,199745329336Anonymous,19861986Anonymous,2000Malik, A.K.,1999pp: 25pp: 25Ashiq, M., M.M. Nayyar and M.L. Shah,1996pp: 82pp: 82Holm, L.G., D.L. Plunknett, J.V. Pancho and J.P. Herberger,1977pp: 609pp: 609Khalid, S.,19941994pp: 23-49pp: 23-49Smith, R.L. and T.H. Smith,1998Pages: 550Pages: 550Oosting, H.J.,19592nd Edn.,Stewart, R.R.,1972pp: 10-28pp: 10-28Nasir, E. and S.I. Ali,1993pp: 1-172pp: 1-172Harding, L.E.,19941994pp: 2-179pp: 2-179Taylor, R.J.,1995pp: 177pp: 177Morrison, I.N.,19861986pp: 277288Oudejan, J.H.,1994pp: 264-290pp: 264-290Rao, J.V.,19871987