Research On Screening Of Resistance To Bentazon Potato Mutant And Its Resistance Mechanism

The potato has been introduced into China for several hundred years and has now become China's fifth largest food crop.At the end of 2014,the ministry of agriculture formally put forward the task of "advancing potato development and potato staple grain" on the national agenda at the national rural work conference.China's potato industry is about to usher in a new stage of development.Weeds are an important hazard in potato fields in China.In early China,the potato planting area was relatively small.The control of weeds mainly relied on artificial and mechanical weeding.With the continuous increase of planting area,the use of herbicides has become a potato field to control weeds.An important means.broad-leaved weeds are one of the main weeds in the potato field.The control of this type of weeds is mainly the use of oxyfluorfen,pendimethalin,and acetochlor for soil closure before seeding.However,potato during the growing season,there is no good safe and effective medicine to prevent broad-leaved weeds.Bendazosone is a herbicide with contact toxicity and strong internal absorption.It mainly controls broad-leaved weeds.However,bentazon may also cause phytotoxicity to some broad-leaved crops while preventing broad-leaved weeds.This limits the use of bendazosone.The successful cultivation of anti-bendason crops can effectively reduce the cost of weeding,increase the efficiency of weed control and can further expand the application market of bentazone.In recent years,the development of genetically modified crops has been very rapid.However,in recent years,genetically modified crops have been controversial.Therefore,until the safety of genetically modified crops has been confirmed,the use of non-transgenic technologies for the breeding of herbicide resistant crops will have more development prospects.In this study,plant tissue culture techniques were used to screen and breed potato varieties that are resistant to bendazosone.At the same time,the resistance mechanism to bentazon was studied by using indoor bioassays,field experiments,and molecular biology techniques,and physiological and biochemical tests were conducted.The molecular mechanism was discussed.The main findings are as follows:(1)When the bentazone concentration was 60 mg/L,the survival rate and germination number of potato tubers were relatively moderate,and the callus could be formed;and when the concentration of bentazone was 40 mg/L,the survival rate and germination number of potato tubers were relatively high,and the callus was basically not affected by bendazosone,it is not conducive to the formation of resistance;when the bendazosone concentration is 80 mg/L,the survival rate and germination number of potato tubers are too low,and the callus is seriously affected.Therefore,60 mg/L is the best screening concentration.(2)After the stems and leaves of sterile potato seedlings were treated with 700 mg/L of benzonsone water,No.4-11,No.4-21,No.4-8,No.4-19,No.DA-50 and No.4-40.The survival rate of the six species was higher,and the survival rates were 84%,90%,92%,88%,82%,and 96%,respectively,showing some resistance to bentazone.(3)Using pot experiments,the resistant potato seedlings with resistance were transplanted and treated with 1296 g a.i./ha of bentazone water solution.In the aseptic seedlings with resistance of 6 different varieties,only the No.4-19 and No.4-40 varieties showed some resistance to bentazone,the survival rate was high,and the survival rate reached 75% and 95%.(4)Three kinds of potatoes after treatment of stems and leaves of No.4-CK,No.4-19 and No.4-40 potato shoots with 1296 g a.i./ha,648 g a.i./ha and 324 g a.i./ha of Bendazon The resistance level of seedlings to bentazon was different.When the concentration of bentazone was 324 g a.i./ha,there was no damage to the leaves of three resistant potato seedlings.When the concentration of bentazone was 648 g a.i./ha,sensitive varieties 4 No damage was observed in some leaves of No.CK,moderate resistant varieties No.4-19,and high resistant varieties No.4-40;when bendazosone concentration was 1296 g a.i./ha,the leaves of sensitive No.4-CK occurred.The whole leaf was scorched,and some of the leaves of the medium resistant variety No.4-19 were scorch,but no damage was observed in the leaves of the high resistant variety No.4-40.(5)At low concentrations of benzonsone,photosynthetic characteristics(photosynthetic rate,stomatal conductance,and chlorophyll content)of potato seedlings with three levels of resistance did not differ significantly.With the increase of benzonsone concentration,high resistance type The decrease in photosynthetic index of potato leaf No.4-40 was significantly lower than that of medium resistance type No.4-19 and sensitive type No.4-CK.Sensitivity of 1296 g a.i./ha bendthasone was used to treat the three resistant levels of potato seedlings.The MDA content of type No.4-CK was significantly higher than that of medium resistance type No.4-19 and high resistance type No.4-40,and medium resistance No.4-19 was slightly higher than that of high resistance type 4-40.The ACC activity of high-resistance type 4-40 was higher than that of medium-resistance type No.4-19 and sensitive type No.4-CK,and after 24 hours,the benzathion was not detected in high-resistance type No.4-40 leaves,but sensitive to it.There are also some residues of bentazon in type No.4-CK and medium resistance type No.4-19.That is,high-resistance type No.4-40 has a strong ability to metabolize and scavenge active oxygen,free radicals,benzonsone and other substances,so that the high-resistance type No.4-40 quickly returns to normal metabolism.These differences are important reasons for the high level of high resistance type No.4-40 resistance.(6)There were fewer significant differences between the resistant and non-resistant varieties before application.There was a significant change in gene expression of non-resistant varieties after application,while there was little change in resistant varieties.Significant differences in genes between resistant and non-resistant varieties were also observed after application.From the molecular level,it was further demonstrated that bentazon did not have a significant effect on the resistant varieties that were induced and cultivated,and explained the apparent differences between resistant and non-resistant varieties after application.