The development of parthenogenetic embryos. (A) Experimental design for the activation of oocytes and the fusion of 2-cells. MII oocytes were activated with or without Cytochalasin B (CB) (SrCl2+CB and SrCl2-CB group, respectively). The 2-cells in the SrCl2-CB group were performed electronic fusion (SrCl2-CB with 2-cell fusion group). (B) The rate of embryo development. The blastocyst rate was significantly lower in the SrCl2-CB group than in the SrCl2+CB group. However, the SrCl2-CB with 2-cell fusion group showed a significantly higher blastocyst rate than the SrCl2-CB group. N, the number of embryos; N in PN formation bars, the number of zygotes formed PN / the number of MII oocytes; N in 2-cell bar of SrCl2-CB with 2-cell fusion group, the number of 2-cells / the number of the fused embryos. Mean ± S.E.M. *,**, ***, p < 0.05 by ANOVA with Tukey analysis (C) The morphologies of embryos at different time points. Scale bar: 100 μm. (D) The distribution of embryos at different time points. The distribution of 4-cells, morula, and blastocyst was significantly lower in the SrCl2-CB group compared to the SrCl2+CB group. SrCl2-CB with a 2-cell fusion group improved the developmental delay at the morula and blastocyst stage. *,**, ***, p < 0.05 by Fisher’s exact test.