Weed control and wheat cultivars (Triticum aestivum L.) responses to metribuzin application rate and timing in Iran

Eskandar ZandA, Mohammad Ali BaghestaniA, Mohsen B. MesgaranB,F, Reza PourazrC, Mansour SaraniD, Masoumeh Younes-abadiE and Sahar MansourianB

A Department of Weed Research, Plant Protection Research Institute, P.O. Box 19395-1454, Tehran, Iran.
B Department of Agronomy and Plant Breeding, University of Tehran, Karaj, Iran.
C Ahvaz Agricultural and Natural Resources Research Centre, Khoozestan, Iran.
D Zabol Agricultural and Natural Resources Research Centre, Sistan and Baloochestan, Iran.
E Gorgan Agricultural and Natural Resources Research Centre, Golestan, Iran.
F Corresponding author.


Field experiments were established at four locations in Iran to evaluate the efficacy of metribuzin in controlling weeds in winter wheat. Metribuzin was applied either post-emergence (POST) or pre-emergence (PRE) at 0, 0.35, 0.52 and 0.70 g a.i. ha-1. At each location three conventionally planted wheat cultivars were tested. In most cases weed control increased with metribuzin rate following a linear or curvilinear trend with an application rate of 0.5 kg ha-1 a.i. providing an acceptable level of control.

PRE applied metribuzin resulted in better control of weeds at Ahvaz while POST treatments were more effective at Karaj with no differences between PRE and POST treatments at two other locations (Zabol and Gorgan). Wheat yields increased with metribuzin rate at two locations (Ahvaz and Zabol) or showed minor (Karaj) to no changes (Gorgan) across application rates. Wheat yields were higher in PRE treated plots than in POST at Ahvaz, but lower at Karaj and did not vary at Zabol (with one exception) or Gorgan.

Wheat cultivars also varied in their responses to metribuzin application rate or timing. Finally, metribuzin could be applied at 0.5 kg ha-1 a.i. (regardless of application timing) but not at higher rates at Ahvaz and Karaj, although higher rates at Zabol and Gorgan could provide both an acceptable level of weed control and wheat yield gain as well. Keywords: Post-emergence, pre-emergence, broadleaved weeds, grass weeds, wheat yield, Iran.


Plant Protection Quarterly (2011) 26 (2) 67-71.