Behavior of soybean genotypes transformed with the AHAS gene which confers tolerance to the herbicide imazapyr

The transformation of the soybean cultivars BR-16 and Doko with the AHAS gene resulted in the development of imazapyr-tolerant herbicide genotypes. A winter greenhouse trial was conducted in order to compare the conventional genotypes BR-16 and Doko with their transformed counterparts under imazapyr application. Some aspects (number of pods and seeds weight) were evaluated and observations showed that genotype BR-16-AHAS was more affected than Doko-AHAS compared to their conventional counterparts. Another experiment was conducted with the two transformed genotypes (AHAS) at a dosage of zero and 100 g i.a. ha -1 imazapyr application in the summer. The relative responses of the two genotypes were similar to the winter results but the herbicide effects differed regarding mainly the most affected position in each genotype. The herbicide imazapyr applied (100 g i.a. ha -1) onto AHAS gene-transformed plants may induce the development of sterile pods. The herbicide and not the inserted gene is responsible for this effect.