Insect-resistant identification and heterosis of transgenic Bt maize

Objective  To study the material expression, yield potential and heterosis of transgenic Bt maize(Zea may), and provide references for genetic modification of transgene materials.

Method  The Reid group elite line PH6WC, the bred inbred lines J1490, J1495 and 4DH10, as well as the introduced line PH1CPS were used as female parents. The Non-Reid based transgenic Bt materials, including 6DH85, J1401, 6DH222, 8DH273 and 8DH279, as well as the self-selected lines J9D207, J1628 and J1688 were used as male parents. Totally 40(5×8) cross combinations according to the NCⅡ design were assembled. The insect-resistant performance and yield potential of transgenic Bt materials were studied.

Result  Part of the Bt genes were deleted or silenced in transgene materials obtained through backcrossing pedigree method, and no corresponding protein was successfully expressed in the filial generations. The cross combination of transgenic Bt materials could partially avoid yield loss due to pest. Comparing to the control variety, combination 4DH10×8DH279 had the best performance with 31.10% yield increase. For combination J1495×J1401, although it contained the Bt gene and it displayed obvious yield increase (65.77% at the highest) compared with the combination without Bt gene of the same male parent, however, it only had 10.04% yield increase compared with the control variety.

Conclusion  High-yield and insect-resistant maize varieties can be bred through combining transgene breeding with conventional breeding as well as tracking and testing.