Influence of herbicides on metabolism and yield formation of sugar beet

As well as affecting the metabolism of weeds, herbicides might also have a detrimental effect on the crop. Pot and field trials were conducted to investigate the influence of different herbicides on the metabolism and yield of conventional and genetically modified, glufosinate- and glyphosate-tolerant sugar beet.

A combination of approved selective active ingredients as used in agricultural practice, led to a reversible disturbance of photosynthesis in all genotypes tested. Genetically modified plants treated with increasing amounts of their complementary herbicide showed different reactions. Application of glufosinate caused a reversible disturbance in the photosynthetic energy transfer of the glufosinate-tolerant genotype. However, no such disturbance was detected for the glyphosate-tolerant genotype.

Further investigations on the effect of the different herbicide treatments on the yield, revealed that, for all genotypes, the application of increasing amounts of selective herbicides, led to a considerable reduction in white sugar yield. Whereas treating glufosinate-tolerant and glyphosate-tolerant genotypes with their respective complementary herbicide had a negative effect on the yield of the former but no detectable effect on the latter.