Herbicide-tolerant varieties (HTVs) are crop varieties that have been developed to be tolerant to a specific herbicide. Given their expansion in France over the past ten years, particularly for sunflower and rapeseed crops, and in response to public concerns, ANSES has reviewed the use of these plant varieties. Like all crop seeds in France, HTVs are not subject to a risk assessment before being placed on the market, and to date, the monitoring of such seeds is not required. ANSES has worked on collecting as much data as possible on the uses of HTVs in France and on gathering the respective views of a variety of stakeholders in order to conduct a review of the status of HTVs. After studying agricultural practices, ANSES confirms that weeds are at risk of developing resistance to herbicides and that there is a chance that the use of herbicides could ultimately increase, as already shown in the 2011 collective expert report by INRA and CNRS. ANSES also emphasises the lack of traceability in the use of such seeds, which hinders the assessment of their agricultural and health impacts. ANSES thus recommends setting up a scheme to monitor any adverse effects due to HTVs.
HTVs are plant varieties that have been developed to be tolerant to herbicides through conventional or genetic techniques. In France, the cultivation of transgenic HTVs is prohibited, and all HTV crops have been obtained through conventional variety selection or random mutagenesis. Under the legislation on genetically modified organisms, organisms obtained by mutagenesis require neither assessment nor marketing authorisation, and to date the monitoring of such organisms is not mandatory. ANSES’s opinion has been formed in the wider context of a debate on the use of biotechnology in agriculture and of the judgment by the Court of Justice of the European Union on organisms obtained by mutagenesis, which is likely to have an impact on the regulatory framework.
An unprecedented review on the use of HTVs in France
Through its expert appraisal, ANSES was able to gather and analyse as much available data as possible on agricultural practices involving the use of HTVs, as well as data from the surveillance of potential adverse effects on human health and the environment. ANSES also interviewed stakeholders to collect a variety of perspectives on the subject, both in the professional community and in civil society. On the strength of these data, ANSES studied the risks associated with the use of HTVs identified by the collective scientific expert appraisal conducted by the French National Institute for Agricultural Research (INRA) and the French National Centre for Scientific Research (CNRS) in 2011. ANSES’s report therefore provides a comprehensive review on the use of HTVs in France.
Varieties used in France, in particular for sunflower and rapeseed crops
Several variety selection or new breeding techniques (genome modification) can be used to produce these plant varieties. Variety selection consists in selecting plants that are naturally tolerant to herbicides and cross-breeding them with existing lines. New breeding techniques include transgenesis, transfer and integration of one or more genes within the genome of a living organism, and several random mutagenesis techniques for selecting organisms with desired traits.
These varieties are used to remove certain technical barriers to weed control. They are also advantageous in that crops can be treated with specific herbicides once the weeds – plants that are a threat to crops – have emerged. In France, the main crop varieties used are sunflower and rapeseed varieties developed to be tolerant to herbicides in the acetolactate synthase (ALS) inhibitor class. According to the data collected, in 2017, land planted with oilseed HTVs accounted for 27% of the sunflower crop area (about 160,000 ha) and for 2% of the rapeseed crop area (about 30,000 ha). The total area of HTV sunflower and rapeseed crops seems to have levelled out since 2017.
The various stakeholders interviewed disagreed on what the varieties were and on which techniques were used to obtain them, as well as on whether or not a specific regulatory framework was lacking. A split was observed between opponents of HTV use, who pointed out the risk of increased herbicide use and the lack of transparency and traceability in the use of such varieties, and supporters of HTVs, who considered them an agronomic solution enabling weed control according to the types of weeds in the fields and a rational use of chemical herbicides.
Lack of traceability in the use of HTV seeds
The experts analysed the available data on the use of HTVs, in particular the data provided as part of the national plan to support the marketing of HTVs, which was implemented in 2012 by manufacturers and agricultural professionals. The surveillance data produced through various phytopharmacovigilance partner programmes were also analysed.
In its expert appraisal, ANSES shows that the data on HTV seed use and HTV agricultural practices, including the use of herbicides, contain many uncertainties. These data are either incomplete or not very representative. For example, neither the French nor the European official variety catalogues include an explicit, reliable list identifying the HTVs that can be grown in France. ANSES therefore highlights the lack of traceability of HTV seeds, which hinders the monitoring of agricultural practices and the use of HTVs in France.
Regarding the surveillance of adverse effects potentially related to HTV crops, the data collected on environmental contamination by herbicides used on HTVs are not specific to HTVs, since these herbicides are also used to control weeds in other crops such as cereal grains. Furthermore, French national plans for the surveillance of pesticide residues have never focused on detecting herbicide residues associated with HTVs in harvested HTV sunflower and rapeseed crops.
Identified risk factors
Although no effects have been observed to date from the data studied, ANSES highlights the risks that could be associated with the use of HTVs. After reviewing agricultural practices, ANSES thus confirms the risk factors already highlighted in the INRA and CNRS expert report, in particular, the development of weed herbicide resistance, an increase in the use of herbicides compared to conventional crops, and ultimately, the contamination of environments by herbicides.
The plots included in the review combined three risk factors that could lead to more herbicides with the same mode of action being used more frequently in crops including HTVs:
- The practice of short crop rotations
- The application of herbicides in the same class of ALS inhibitors for weed control in oilseed and cereal grain crops
- The use of herbicides on HTV plots that remain similar to plots without HTVs
Introducing HTV surveillance in France
Following its expert appraisal, ANSES stresses that the limitations of the data collected in terms of their quantity and quality did not enable it to reach a decision on potential adverse effects or to carry out a risk assessment.
ANSES thus recommends setting up a programme to monitor HTV seeds so that they can be traced until they are actually used in crops. This programme will help improve knowledge of the associated agricultural practices and increase the surveillance of residues from herbicide substances associated with HTVs for sunflower and rapeseed crops in relevant regions.
In order to assess the potential health effects of HTVs, ANSES recommends implementing a specific study to verify whether any particular metabolites are formed that may not have been included in the European assessment on plant protection active substances.
Lastly, ANSES recommends raising awareness among farmers of the risk of herbicide resistance development in weeds.