A Study on Weed Flora and Importance Value Index of Weeds in Wheat Crop

Weeds are an important problem because they reduce the yield and quality of wheat. This study was carried out to determine the phytosociology of weeds in wheat fields of Siirt, Turkey. A square-frame inventory method was used that was randomly released at least four times from 90 different locations between March and May in 2019. A total of 71 weed species belonging to 20 different families, one of which is grass (12 species) and 19 broadleaf (59 species) were identified. Asteraceae (with 15 species) were identified as the predominant family, followed by Poaceae (with 12 species), Brassicaceae and Fabaceae (with 8 species). The highest frequency, density and abundance values were determined Avena sterilis L. (83%, 11.4 plant m-2, 32.8%), Sinapis arvensis L. (81%, 9.6 plant m-2, 41.3%), Ranunculus arvensis L. (77%, 4.3 plant m-2, 24.4%), Galium aparine L. (66%, 8.2 plant m-2, 12.8%), and Cirsium arvense (L.) Scop. (61%, 5.5 plant m-2, 29.0%) species were the maximum. When the above values are calculated relatively, importance value index (IVI) were detected Avena sterilis L. (22.3%), Sinapis arvensis L. (22.2%), Papaver rhoeas L. (15.9%), Cirsium arvense (L.) Scop. (14.1%), and Galium aparine L. (13.5%) species were the highest. According to the economic threshold (according to the current literature) Avena sterilis L. and Sinapis arvensis L. were identified as noxious weeds. This research will shed light on the determination of the noxious weeds, economic threshold and environmentally-friendly integrated weed management tactics to be developed in wheat. Keywords: Wheat, Weeds, Frequency, Density, Abundance, Importance value index DOI: 10.7176/JSTR/6-01-05