Comparison with Cotyledonary Node and Embryonic Tip Regeneration System in Soybean[Glycine max(L.)Merrill] and Genetic Transformation of SR1

In this study,the soybean cotyledonary node and embryonic tip were used as explants to transform SR1 gene into Hefeng 25 and Hefeng 35,which are susceptible to soybean Phytophthora root rot.The results showed that the regeneration of Hefeng 35 reached 96.1% and 79.1%,in embryonic tip and cotyledon node system,respectively,which was significantly higher than that of Hefeng 25(66.45% and 74.4%).The mean regeneration period of Hefeng 35 in embryonic tip and cotyledonary node transformation system was 40 and 68 d,respectively.When the explants of the two systems grew on the SIM or SEM for 20 days,the regeneration frequency of embryonic tip(96.1%)was higher than that in cotyledonary node transformation system(77.8%).The SR1 gene was transferred into Hefeng 35 by embryonic tip explants,and obtained 6 transgenic plants.