Cloning Strategy of Barnase Gene (Extracelluar Ribonuclease Gene) Study on Pollen Fertility in Transgenic Maize with Transgene of Zm13-Barnase Induction of Male Sterility in Oilseed Rape by TA29-Barnase Gene Development and Standardization of Qualitative PCR Detection Method Targeting barnase Gene Male Sterile Tobacco Plants Obtained by Genetical-Engineering A STUDY ON THE INTRODUCTION OF MALE STERILITY OF ANTIINSECT TRANSGENIC Populus nigra BY TA29-BARNASE GENE