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English grain aphid Macrosiphum avenae is the main pest on the ear of wheat during the drought year,which result in decreasing of yield and quality of wheat. In this study, RAPD-PCR mehtod was adopted to analyse the DNA mutation of a generation of clones under the induced condition, At the same time, optimized the procedure of RAPD-PCR reaction system of small-sized insect, selecting 48 RAPD primers to obtain 6 items of primers which can be used for evaluating the polymorphism of the total clones including the induced aphids under insecticide, high-temperature, ultravbiolet and the normal ones. The methods of Cluster analysis based on the data of similarity index and Nei’s genetic distance(D) induced the distribution on the level of every Nei’s genetic distance. The main result as follows:1. Improved the existed RAPD system to make it more stable and economical. The total reaction volume is 25ul, including 2.5ul 10×buffer, 2.5ul dNTPs(10mM), 2.5ul MgCl2(25mM), 1ul random primer(33ng/ul), 0.1ul Taq polymerase(5U/ul), 1ul template DNA(about 25ng/ul) and 15.4ul superpure water.2. Selected 48 RAPD primer to analyse the polymorphism of macrosiphum avenae, the fragments ranged from 200bp to 2,000bp and the number of fragments which the primers amplified is 1-13.These results provide the reference for primers selection in the subsequence RAPD analysis.3. Put in the ultraviolet at a distance from 20cm in the normal temperature, the average genetic distance of thirty-seven english grain aphids was 0.2028,and on this level, the rate of DNA mutation was about 30.56%.4. Under the gradually increasing temperature from 20℃to the extreme temperature(35℃), the average genetic distance of thirty-six aphids was 0.1667 and the rate of DNA mutation was about 33.33%.5. The average genetic distance of thirty-nine aphids was 0.1846, when these aphids were sprayed organophosporus insecticide(4000×) and the rate of DNA mutation was 41.03%.6. In the normal condition, several of thirty-two aphids produce DNA mutation, and the average genetic distance was 0.08125 and the rate of DNA mutation was 34.375%. The net genetic distance under the induced condition (ultraviolet, high-temperature, insecticide) <WP=5>respectively were 0.1216, 0.0855, 0.1034, and on these levels, these rates of mutation were 47.67%, 80.56%, 56.67%. These genetic distance under induced condition was longer than that of different population of same species(0.031) and shorter than that of different suberspecies of same species (0.230). These mutation didn’t reach the level of subspecies, just belong to the sub-level of subspecies.
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