M.A. Thesis:

The effect of adding adjuvant on reducing the dose of sulfosulfuron+metsulfuronmethyl

In order to investigate the effect of adding adjuvant on reducing the dose of sulfosulfuron+metsulfuronmethyl, herbicide a field experiment was conducted in a private farm in Hekmaabad village of Sabzevar in 2013-2014 in a factorial experiment based on a randomized complete block design with three replications. Factors were: The test factors were: adjuvants doses at the two levels: recommended (1% of the source of citoute) and recommended +50% and the reduced amount of sulfosulfuron + methyl sulforon methyl (total) herbicide at five levels (0, 25, 50, 75 And 100% recommended dose (45 g ha-1 from WG 80% formulation). Weed weight, weed damage, crop damage, plant height, fertile tiller number, number of seeds per spike, 1000 seed weight, biological yield and economic yield were measured. The results showed that the addition of adjuvant caused a further reduction of weed dry weight and a increased percentage of damage to weed and crops, and biological and economic yield, while not affecting other traits. The logistic dose-response result showed that herbicide required to reduce the weed weight by 50% in the recommended dose of adjuvant was 61.29% and for recommended+50 dose adjuvant was 41.93%. The use of recommended herbicide dosage reduced the weed weight, weed damage, crop damage, plant height, number of fertile tillers, number of seeds per spike, 1000 seed weight, biological yield and economic yield as compared to control. There was no significant difference with 75% recommended dose. Overall, the results showed that in the studied region, A good economic yield can be achieved by 25%reducing herbicide dose.

Keywords: Dose-response, Low herbicide dose, Weed, Wheat, adjuvant