Identification Of Insect Resistance And Inheritance Of Transgenic Bt Gene In Maize

The identification of insect resistance has been made on the four backcross materials by inoculating insect eggs into leaf spindle in the field and indoor PCR.Based on the result of identification of insect resistance of the four BC3 and BC4 materials, both identification of insect resistance in the field and PCR detecting were used to analysis the four materials.The results are as fellows: 1) The insect resistance of the four materials in BC3 and BC4 is enhanced standardly.The herds of the four materials are between positive CK (CK1)and negative CK(CK2),but are better than CK2. 2) In herds, individuals are remarkablely different from high resistance(HR) to high susceptivity(HS). All of the individuals of high resistance(HR), resistance(R),medium resistance(MR) behave better than negative CK(CK2). For example,individuals' number of insect cavity and the lenth of insect cavity of 8085 Bt including HR ,MR and R are respectly 0.33 and 1.02cm.Comparing with their negative CK(CK2), they separately decrease by 86.8% and 93.5%.however ,there is a remarkable difference between the herd resistance of Zong3Bt and CK2.The insect resistance of MR to HR and HR individuals is much more outstanding than CK2. 3) The result of PCR shows that Mendelian segregation was observed in BC3 and BC4. 4) Identification of insect resistance in the field and PCR detecting can not always correspond . In 98 individuals of BC3, identified with external Bt toxic protein gene, the numbers of individuals of high resistance(HR), resistance(R), medium resistance(MR), susceptivity(S), high susceptivity(HS ) are respectively 73, 5, 7, 2 and 11.The ratio of insect resistant plants is 86.7%.