Determination of Population Indices and Distribution Map of Weeds in Rainfed Wheat Fields of Kermanshah Province

In order to identify and determine weeds distribution in rainfed wheat fields of Kermanshah province, 58 fields in 7 counties were investgated during 2001 and 2009. After weed survey the charsterictics of weed species were evaluated. Then density, frequency, uniformity, mean density, abundance index, Shannon- Weaver diversity index and Simpson index were determined. In rainfed wheat fields of Kermakshah province 91 weed species were identified out of which 15 species belong to grass weed and 53 species belong to broadleaf weed. Poaceae, Fabaceae, Asteraceae and Rubiaceae were the most important families with, 57, 35.5, 34.6 and 18 percent of FIV, respectively. Based on the result of this study Galium tricornatum, Vicia hyrcanica, Vaccaria pyramidata and Anthemis cotula were the dominant broadleaved weeds. Avena ludoviciana, Hordeum spontaneum and Bromus tectorum were the most important grass weeds. In addition the most important troubeling preharvest weeds were Convolvulus arvensis, Carthamus oxyacanthus and Glycyrrhiza glabra in rainfed wheat fields. Shannon-Weaver diversity index showed the highest species diversity were in Kermanshah with 2.67 and the lowest species diversity in Songhor and Sarpolezohab were with 1.8 and 1.9, respectively.