Resistance Identification, Genetic Analysis And Backcross Breeding Of Transgenic Soybean Toleranl To Glyphosate

In order to know more about the inheritance of herbicide resistance in transgenic soybean, and tobreed new varieties with desired agronomid performances and herbicide resistance, the introducedpossible glyphosate-resistant soybean materials were screened by both phenotypic observations andmolecular identifications. Furthermore, the crosses between the identified transgenic parents and localelite varieties were made, and the inheristance of targeted genes were analyzed by oberservingglyphosate-resistance in different progenies. Finally, some lines with excellent agronomic traits andhigh herbicide resistance were obtained, which can pave the way for the the uses of transgenic soybeanin production.At the beginning of this study, fifty introduced soybean varieties were examined using phenotypicassays and PCR detections. In phenotypic experiments,41%glyphosate isopropylamine solution wassprayed on soybean leaves. After attaining positive phenotypic samples, CaMV35S promoter, NOSterminator, EPSPS genes were assessed by PCR reaction further to confirm related genes in transgenicsoybean. The results indicated that, all of the fifty introduced soybean varieties were positive in theabove tests.To explore inheritance of herbicide resistance in transgenic soybean, the varieties with optimalagronomic characters were used to cross with local non-transgenic soybean varieties. After crossing andbackcrossing, all of the offspring were sprayed by41%glyphosate isopropylamine solution, and theherbicide resistance rate in soybean offspring was calculated for genetic analysis. The results showedthat EPSPS gene separated from F₂generation, and herbicide resistance rate in F₂, F₃and BC₁generations were3:1,5:1and1:1, respectively, indicating that the inheritance of this trait fitted intoMendel law, and the herbicide resistance was controlled by a pair of dominant alleles. Furthermore, theselection of the offsprings resulted in the obtaining of the elite lines with herbicide resistance from thetransgenic soybeans and comprehensive agronomic traits similar to that of local parent cultivars, such asHefeng50, Hefeng51, Suinong14, etc.