Scientists Assess Gene Flow from HT Soybean to Conventional Soybean in China

Scientists at Chinese Academy of Agricultural Sciences and Chinese Academy of Tropical Agricultural Sciences characterized the transgene flow from herbicide tolerant (HT) soybean (AG5601) to conventional soybeans. They evaluated the natural out-crossing rate using 36 conventional soybean varieties interplanted with AG5601. Then they evaluated the drift distance of the HT gene (cp4 EPSPS) from AG5601 to soybean cv. Zhonghuang13 using the progenies harvested from eight directions at different distance. The relationship of gene flow of AG5601 with flowering synchronization days or insect pollinators of each variety was analyzed using regression analysis.

Results showed that 32 of 36 tested conventional soybean varieties had surviving progenies after two times of sprays of glyphosate, and 49 of 41,679 progenies were verified to be glyphosate-tolerant heterozygous offspring. The farthest distance between AG5601 and cv. Zhonghuang13 at which out-pollinating was still able to be observed was 15 meters. Regression analysis showed a positive link between cross-pollination frequency and flowering synchronization days or pollinator insects. Based on the results, the researchers recommend that when HT soybean is released to the field, it should be significantly separated with the conventional soybean in space and cultivation time with efficient insect control during flowering.

Read the research article at http://link.springer.com/article/10.1007/s11738-014-1539-3.