| In recent years,with the changes in crop layout and climatic conditions in China,the replacement of maize varieties and the gradual expansion of corn cultivation area,the types of com pests and the degree of damage have also changed greatly.The occurrence and damage of con aphids have increased year by year.It has a serious impact on the yield and quality of con.Therefore,screening and utilizing maize resistant varieties to reduce the damage of maize through its own insect resistance is an important measure to control corm pests and an important part of the integrated pest management system.In this study,three pairs of maize varieties,IE09S034,808 and Dabei Nong,were selected.From the physical properties of corn leaves,the main biochemical substances and the activities of detoxification enzymes,protective enzymes and digestive enzymes in different species of corn,the transgenic maize and anti-caries were studied.Sexual relationship,explore the resistance mechanism of transgenic com to aphids,and provide theoretical basis and effective methods:for scientific prevention and control of corn aphids.The main findings are as follows:1.The field system survey showed that the population growth and decline dynamics of aphids on maize varieties during the whole growth period were basically the same,but the difference between the transgenic varieties and the conventional com parents was larger.The autumn corn borer began to occur in mid-August,and peaked from late August to early September.After that,the population decreased,and the population of the field decreased rapidly in late September.The summer con borer appeared in the middle of May,and the early population rose slowly.In late May,the population reached its peak,and in the middle of June,the field locusts gradually disappeared.In addition,the survey of the population density of corn borer showed that the number of com borers on the transgenic varieties was significantly lower than that of the conventional corn parents.2.The results of growth and reproduction of com borer showed that the developmental stages of aphids of IE09S034,808 and Dabeiong transgenic maize varieties were longer than the corresponding conventional parents,among which,on the IE09S034 transgenic variety,1,2,4 The developmental duration of nymphs was 25.15%,21.25%,and 17.54%higher than that of the conventional cultivars.There was also a significant difference in the litter size of locusts on various maize cultivars.IE09S034,808,and Dabei GM transgenic maize cultivars The litter size was lower than their conventional parents,which were 20.64%,25.81%,and 22.01%lower respectively.The survival rate of aphids on transgenic corn was lower than that of their corresponding conventional parents.The analysis of the population trend of corn borer found that the trend index of the aphid population of the three transgenic maize varieties was lower than that of the conventional parental species.Among them,IE09S034,808 and Dabei Nong were 42.67%,53.02%and 44.40%lower than the corresponding parents respectively.3.The analysis of the physical characters of maize leaves showed that the leaf wax content,chlorophyll content and vascular bundle depth of transgenic maize varieties were significantly higher than those of conventional parental varieties,while the leaf hair density was lower than that of conventional parental varieties.Correlation analysis showed that there were significant correlations between the aphid population trend index and waxy content,chlorophyll content,hair density,and vascular bundle depth in three growth stages,including seedling stage,ear stage and flower size.The relatively strong correlations were chlorophyll content,wax content,and vascular bundle depth,indicating that the higher the chlorophyll content and wax content of the leaves at each growth stage,the deeper the vascular bundle depth,and the more resistant the variety to the aphids.Strong.The contents of Si,K,Ca and other elements in the leaves of different transgenic varieties were higher than those of their conventional parents.Among them,the Si content of IE09S034 and 808 transgenic varieties was significantly higher than that of their parental controls in three growth stages.The results showed that the aphid population trend index and the Si,Ca and P elements on the leaf surface had different significant correlations in the three growth stages.Among them,the P element content in the leaves had the most obvious influence on the aphid insects.In the period,the content of P element in leaves had the most obvious effect on the amount of carnivore,followed by the content of element ca and element of Si.In the flower stage,the content of P element had the most obvious effect on the amount of carnivore,followed by the content of Ca element.The selective test of aphids on maize leaves showed that the corm borers had obvious selectivity to the volatiles of different maize varieties,and the selectivity to volatile odor of transgenic maize leaves was significantly lower than that of the control.The determination of volatiles in com leaves was determined.The differences in leaf volatile components between transgenic maize and its control were found.The relative percentages of olefins in the volatiles of transgenic varieties were higher than those in the control,while the relative percentages of aldehydes were lower than the control.Corn aphids have obvious selectivity to the leaf color of IE and Dabei agricultural varieties,and the selection rate of leaf color of transgenic varieties is significantly lower than that of the control.The analysis of biochemical substances related to insect resistance in leaves showed that the content of soluble sugar,total phenol and flavonoids in transgenic corn leaves were significantly higher than that in the control,while the content of proline and protein was significantly lower than that of the control.Correlation analysis showed that there was a significant negative correlation between the aphid population trend index and soluble sugar,phenolic compounds and flavonoids at different stages.Among them,the content of phenolic compounds in the leaves and the grain stage was the most obvious effect,followed by the content of soluble sugar and flavonoids.4.The analysis of the enzyme activity in aphids showed that the activities of acetylcholinesterase(AchE),detoxification enzyme,protective enzyme and digestive enzyme in the aphids on the transgenic maize were lower than the control,and the IE09S034 and 808 transgenic maize varieties were fed.The activity of acetylcholinesterase(AchE)in aphids was 48.68%and 50.70%lower than that of the control,respectively.The activity of peroxidase(POD)in aphids fed IE09S034 and Dabeiong transgenic maize was 18.52%and 16.41%lower than that of the control,respectively.The activity of catalase(CAT)in aphids fed IE09S034 and Dabeiong transgenic corn was 25.81%and 34.33%lower than that of the control,respectively.5.The indoor virulence test and field efficacy test of several aphids against com borers showed that 7%biphenyl thiabensamine suspension,50%nitenpyram soluble granules and 25%thiamethoxam water dispersion have good toxicity to the aphids on the transgenic and control varieties,and have good control effects,and have quick effect and long-lasting effect.They can be widely used in production;19%bromine Cyanamide(DuPont-Verima)suspension has good toxicity to com aphids,but it has general control effect on com aphids;The poisoning effect and control effect of 80%enepyridine pyridone water dispersible granules and 22%flonicamidil suspension on com borers are common. |
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