Distribution of dominant weed species in winter wheat at Tabriz county

Weed flora surveys were conducted to determine the distribution of dominant weed species in wheat (Tirticum aestivum L.) fields at Tabriz county. Only 3.91% of weeds were assertive and observed in more than 60% of fields, but 89.84% of weeds were found in less than 30% of fields. Assertive weeds were corresponding with 13 abundant weed species. These weeds were adapted to farmer's management methods. The major families for these noxious weeds were Chenopodiaceae, Brassicaceae, and Poaceae with 3, 2, and 2 dominant species,respectively. Acroptilon repens (L.) DC., Eremopyrum Bonaepartis (Spreng.) Nevski, and Cardaria draba (L.) Desv. with 114.1, 105.48, and 100.39 DI (dominance index) were dominant in winter wheat fields at Tabriz county. A. repens (L.) DC. and C. draba (L.) Desv. had highest relationship together. Also, highest correlation was observed between Polygonum aviculare L. and Chenopodium album L. These weeds were observed in more than 60% of fields. E. Bonaepartis (Spreng.) Nevski with mean density 3.26 plants m-2 had highest density, higher values of density shows that this weed has more competitive or reproductive ability than other weeds. And also, higher value of uniformity for E. Bonaepartis (Spreng.) Nevski represents that this weed is more compatible with the soil and climate conditions.