Fecundity
F1, F2, and F3 hybrids mainly grew well and produced more pods and more seeds than GM soybean, and their fertility increased similarly to that of wild soybeans. Importantly, there were no significant differences in F2and F3 RR, RS or SS plants in pod and seed numbers per plant, the EPSPS gene and its copy number did not significantly affect the fecundity of the hybrids. In a two-year field experiment, Yook et al. (2020) reported that F1 and F2 hybrids had a similar number of pods and seeds as wild soybean, and no differences were found for 100-seed weight between F1 hybrid and wild soybeans; however, F2hybrids had a higher 100-seed weight than their wild soybean counterparts. Similar to those of the studies described previously (Yook et al. 2020), our results also showed that F2 and F3 hybrids had significantly higher 100-seed weights than their wild soybean counterparts, and no parameters significantly differed among RR, RS and SS in the F2 or F3 population. Our findings and those of previous studies suggest that hybrids possess higher seed production potential (Guan et al. 2015; Kuan et al. 2015; Yook et al. 2020), the fecundity benefit could confer hybrid more competitive for natural selection than their wild parents.