Herbicide-resistant varieties currently play a key role among the genetically modified arable crops soyabean, cotton, oilseed rape, and maize grown worldwide. Reasons for the quick increase in areas cultivated by herbicide-resistant crops are, among others, shortcomings of existing chemical weed control solutions in these crops and an increase in cultivation methods using minimum tillage techniques. As a countermove, the minimum or no-till cropping area increased significantly, due to the introduction of herbicide-resistance technology, particularly in soybeans. Decision criteria during the past 8 years for choosing adequate weed control systems using herbicide-resistant or conventional varieties were: varietal performance, superior crop tolerance and application timing flexibility, efficacy of post-emergent weed control measures in dry areas, controlled weed spectrum, and duration of activity including control of resistant weed biotypes. Due to restrictive labelling instructions and lack of authorization in main overseas export markets, including European liability and coexistence rules, sales restrictions are essential decision parameters for individual farms. The technical progress of herbicide-resistance technology is achieved in the short and medium term by further development of spraying sequences and tank mixtures towards ready-formulated mixtures of complementary herbicides with conventional residual mixture partners. To control and prevent the spread of new herbicide-resistant weed biotypes, complementary herbicides are combined with other modes of action. Further developments are combinations of various other transgenic traits with transgenic herbicide resistance and herbicide-resistant varieties of (worldwide) less important minor crops without satisfying conventional chemical weed control solutions. For long-term developments, plastid transformation techniques to prevent the unwanted dissemination of transgenic features could gain importance.
