Exploration On The Quick-test And Herbicide Screening Of Resistant Grass Weed In Wheat Field

In recent years,with the excessive dependence and long-term use of herbicides,led to a number of resistant weeds rising sharply.As one of the important food crops of wheat,the resistant weeds occurred is most serious.The number of herbicide-resistant species of wheat field was 21 species,gramineae biological type as many as 10,resistance is very outstanding.there are two main categories of herbicide in wheat field: Acetyl coenzyme A carboxylase(ACCase)inhibitors and acetolactate synthase(ALS)inhibitors,but for some agents have been repeatedly reported that prevention failures.As for the rapid development of the resistance in wheat field weeds,be urgently need a rapid detection method to the actual demand and select effective herbicide to the resistant species,giving farmers to use herbicides more effectively.This study chose growth consistent Alopecurus japonicus as experimental material,for the feasibility analysis and further explored to Resistance In-Season Quick test;the resistance occurs serious Beckmannia syzigachne,Alopecurus japonicus and Sclerochloa kengiana as the experimental material,whole-plant dose response experiments were conducted in the greenhouse to select effective herbicides;Field efficacy trials in Anhui Province to validatethe identify dose and selected herbicides.The results could be summarized as follows:1.The explored to Resistance In-Season Quick test.A.japonicus populations in different growth period after transplanting have demonstrated a clear ability to regrowth;This was confirmed that populations grew healthily on control plates.Under the influence of different concentrations of herbicide,resistant and susceptible populations show different tolerance,with the growth of the plant,the differences between the two populations get smaller and smaller.Whether root length inhibition rate or buds long inhibition rate as the index,the resistance index of Rr-1 populations becomes lower and lower.This suggests that the RISQ method can test resistant,but the two populations have different levels of different periods,and the plant is smaller,the greater the difference.2.The identification dose of A.japonicus populations.Combined with the actual use conditions and test results of different plant growth period ahead,the two leaves plant were selected to identify dosimetry.Mortality rate as indicators,and in the dose of 345?g / L,resistant and susceptible populations are quite different,sensitive population smortality rate over 95%,resistant population mortality rates of 0.So preliminary selected 276 ~ 345 ?g /L for differential dose range.3.Herbicides screening to three kinds of resistant weeds.The three resistant populations had evolved high resistance to fenoxaprop-P-ethyl,pinoxaden and clodinafop-propargyl,low to moderate resistance to part of ALS herbicides.Flucarbazone-Na displayed poor control effect to the resistant populations,GR90 s were from 67.31 to 114.39 g a.i./hm2;pyroxsulam could control the Rr population effectively,and the GR90 was 4.67 g a.i./hm2;mesosulfuron-methyl showed high efficacy for the three resistant populations,but there was risk of resistance in Rr population,the resistance index was 2.0.Three new herbicides without commercialization in China were also used in this study,among which,sulfosulfuron could control Ry and Rr populations well,while propoxycarbazone-sodium showed high efficacy in controlling Rw population.Flufenacet was the only herbicide which performed ideal effects to all Rw,Rr and Ry populations with control efficacies more than 90% at the recommended field rate(120 g a.i./hm2).4.Field efficacy trials.The Rapid test results of A.japonicus populations that collected from the field in the second leaf to fenoxaprop-P-ethyl show that: Plants grow well in 386.1?g /L,and initially concluded that A.japonicus populations in this field showed resistance to fenoxaprop-P-ethyl.The subsequent efficacy trials proved that A.japonicus populations had evolved resistance to fenoxaprop-P-ethyl and clodinafop-propargyl.The flufenacet had general efficiency of 74.3% at high doses in 60 d.Pinoxaden and mesosulfuron-methyl were better efficiency above 80% in 60 d,pyroxsulam had the best effect,reaching about 90%.There are some differences between the results of greenhouse experiment.