The objective of this study is to confirm the target traits and genetic stability of transgenic glyphosate- resistant cotton GGK2 and provide technical support for its commercialization.

T₃, T₄, and T₅ transgenic cotton plants GGK2 were subjected to insertion site-specific PCR, Southern blot, ELISA, bioassays in the laboratory and field, analysis of target herbicide tolerance, and investigation of nutritional constituents.

The results indicated that the target genes, GR79 EPSPS and GAT, were integrated into the cotton genome as single copies and stably inherited in GGK2 plants. In GGK2 cotton, GR79 EPSPS, GAT, and NPTⅡ proteins were expressed at different stages and in different tissues, with relatively high expression levels in the leaves. At the four-leaf stage, bud stage and boll opening stag, the expression levels in leaves were 128.7-192.4 µg·g^-1, 24.4-35.0 µg·g^-1, and 17.0-23.9 µg·g^-1 fresh weight for GR79 EPSPS, GAT, and NPTⅡ, respectively. In the field, transgenic cotton GGK2 tolerated up to four times the recommended medium dose of glyphosate application. No significant differences were observed in agronomic traits and nutritional constituents compared to the control, Coker312.

These data demonstrate that transgenic cotton GGK2 is genetically stable and highly resistant to herbicides. Therefore, it can be utilized for breeding high-glyphosate- resistant commercial cotton varieties.