Cry Toxin Expression on Different Plant Parts and Crop Stages Among Transgenic Bt Cotton Hybrids

Expression of Cry toxins was estimated in leaves, squares and bolls of Bt cotton hybrids, viz. JKCH 1050 Bt, Yuvraj Bt and MRC 7017 BG II, Ankur 3028 BGII and NCS 855 BG II at different crop stages (105, 120 and 135 days old plants) by sandwich ELISA using quantiplate kits. The mean Cry1Ac expression was maximum in Yuvraj Bt (4.56 μg g⁻¹) followed by BG II, MRC 7017 (3.92 μg g⁻¹), Ankur 3028 (3.70 μg g⁻¹), NCS 855 (3.62 μg g⁻¹) and JKCH 1050 Bt (3.02 μg g⁻¹). Significantly higher Cry1Ac was estimated from leaves (4.04 μg g⁻¹)followed by squares (3.97 μg g⁻¹) and bolls (3.51 μg g⁻¹). The concentration of Cry2Ab in fresh plant tissues among BG II hybrids was maximum in MRC 7017 (20.89 μg g⁻¹) followed by Ankur 3028 (19.58 μg g⁻¹) and NCS 855 (18.61 μg g⁻¹). Significantly, higher Cry2Ab was estimated from leaves (20.34 μg g⁻¹) as compared to squares (20.01 μg g⁻¹) and bolls (18.94 μg g⁻¹). Higher expression of Cry2Ab was estimated from 105 days old plants (20.43 μg g⁻¹).as compared to 120 (19.81 μg g⁻¹) followed by 135 days old plants (19.04 μg g⁻¹).