Study On The Resistance Of Barnyardgrass (Echinochloa Crusgalli(L.) Beauv) To Four Herbicides In Corn Fields Of Heilongjiang Province

Heilongjiang province is a major corn producing area in our country, corn planting area reaches6.642 million hectares, which shares 47% of the total grain crops sown area of Heilongjiang. Heilongjiang province is one of the earliest use of herbicides in China. Since the 1980 s Atrazine, 2,4-D-butyl ester and other herbicides have been widely used in corn fields of Heilongjiang. Echinochloa crusgalli(L.) Beauv is the Annual grass weeds, massively occurring in corn fields.The corn losses will be 15% if Per square meter has 20 barnyardgrass. 23 Barnyardgrass biotypes collected from 12 areas of Heilongjiang province were used to determine the resistant level of Barnyardgrass to 4 common herbicides by using agar method and whole plant method. With Agar method and Whole plant bioassay,studying Agar method and Whole plant bioassay in degrees. At the same time determining the Barnyardgrass’ ALS,GSTs,POD,SOD and CAT activity and researching the resistance mechanism of Barnyardgrass preliminarily. The results are as follows:(1) Determine the resistant level of Barnyardgrass to 4 common herbicides by using agar method and whole plant method. Concluded as follow:1)Barnyardgrass had a certain resistance to Nicosulfuron and Atrazine by means of whole plant method.The whole plant method for the determination of 23 biotypes of Nicosulfuron resistance results: Binxian02 developed an intermediate level of resistance with the resistance index(RI) of 14; Binxian01,Jixi02,Acheng02 and Zhaodong01 developed a low level of resistance with the RI of 9.77, 5.80, 5.47 and 5.03; Qinggang01,Qiqihaer01 and Qinggang02 biotypes is in decreased sensitivity stage, whose RI is 4.00, 3.95 and 3.45; Other 15 biotypes are sensitive to Nicosulfuron. Sensitive Barnyardgrass biotypes accounted for 65% of the tested 23 biotypes, other biotypes are resistancewith different degrees to Nicosulfuron,which account for 35% of the tested biotypes.The whole plant method for the determination of 23 biotypes of Atrazine resistance results:Binxian02 developed a low level of resistance with the RI of 5.01;Jixi02 and Wuchang02 biotypes is in decreased sensitivity stage, whose RI is 3.40 and 3.23;Other 20 biotypes are sensitive to Atrazine. Sensitive Barnyardgrass biotypes accounted for 87% of the tested 23 biotypes, other biotypes are resistance with different degrees to Atrazine,which account for 13% of the tested biotypes.2) Barnyardgrass are sensitive to Mesotrione and Acetochior by means of whole plant method.The whole plant method for the determination of 23 biotypes of Mesotrione and Acetochior resistance results:23 biotypes are sensitive to Mesotrione and Acetochior,whose RI is less than 3.3) Compare similarity by Agar method and Whole plant bioassay.Agar method and whole plant method determine that 19 biotypes have the same resistant level to Nicosulfuron in tested 23 biotypes, which conformity accuracy is 82.61%. The measurement results of agar method bigger than whole plant method for the remaining four biotypes. Because Agar method does not leak sieve the resistant Barnyardgrass to Nicosulfuron, so can instead of whole plant method when determine the resistant level of Barnyardgrass in corn fields to Nicosulfuron.Agar method and whole plant method determine that 19 biotypes have the same resistant level to Atrazine in tested 23 biotypes, which conformity accuracy is 82.61%. The remaining four biotypes have three biotypes Agar method assay resistance index greater than whole plant method results,so Agar method does not leak sieve the resistant Barnyardgrass to Atrazine.At the same time agar method have some advantages such as less work and little time, agar method can be the major method to determine the resistant level of Barnyardgrass in corn fields to Atrazine.(2) Enzymatic activities in Barnyardgrass biotypes of different resistant level are determined to Nicosulfuron and Atrazine, The results are as follows:1)Enzymatic activities in Barnyardgrass biotypes of different resistant level are different to Nicosulfuron,concluded as follow:The relation of POD and CAT enzyme activity with the degree of resistance to Nicosulfuron is not close. Making Binxian02 biotype as high resistant biotype(R), Zhaodong01 biotype as medium resistant biotype(M) and Xuexiao biotype as sensitive biotype(S). After treated with Nicosulfuron, the POD and SOD activity of these three biotype has no irregularity in the average rate of change and peak size. So the resistance of Barnyardgrass to Nicosulfuron is not related with POD and SOD.There is little relationship that SOD enzyme activity and the degree of resistance to Nicosulfuron. Making Binxian02 biotype as high resistant biotype(R),Zhaodong01 biotype as medium resistant biotype(M) and Xuexiao biotype as sensitive biotype(S). After treat with Nicosulfuron, the POD and SOD activity of these three biotype has no irregularity in the average rate of change,but the peak size showed that R>M>S. There is little relationship that SOD activity of Barnyardgrass and the degree of resistance to Nicosulfuron.The resistant level of Barnyardgrass to Nicosulfuron is related with ALS. Making Binxian02 biotype as high resistant biotype(R),Zhaodong01 biotype as medium resistant biotype(M) and Xuexiao biotype as sensitive biotype(S). After treated with Nicosulfuron, the activity of ALS were all raise first and then declined. The degree of inhibition was S>M>R, recovery capability was R > M>S. So ALS is one of the reasons of resistance to Nicosulfuron.2) Enzymatic activities in Barnyardgrass biotypes of different resistant level are different to Atrazine,concluded as follow:The relation of SOD and CAT enzyme activity with the degree of resistance to Atrazine is not close. Making Binxian02 biotype as high resistant biotype(R), Zhaodong01 biotype as medium resistant biotype(M) and Xuexiao biotype as sensitive biotype(S). After treated with Atrazine, the SOD and CAT activity of these three biotype has no irregularity in the average rate of change and peak size. So the resistance of Barnyardgrass to Atrazine is not related with SOD and CAT.The resistant level of Barnyardgrass to Atrazine is related with POD and GSTs. Making Binxian02 biotype as high resistant biotype(R), Zhaodong01 biotype as medium resistant biotype(M) and Xuexiao biotype as sensitive biotype(S). After treated with Atrazine, the activity of POD were all raise first and then declined. The average rate of change was R>M>S, the peak size showed that R>M>S. The resistant level of Barnyardgrass in corn fields to Atrazine is related with POD.