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In sugar beet production, weed control is one of the most important and most expensive practices to ensure yield. Since glyphosate-resistant sugar beets are not yet approved for cultivation in the EU, little commercial experience exists with these sugar beets in Europe. Experimental field trials were conducted at five environments (Germany, Poland, 2010, 2011) to compare the effects of glyphosate with the effects of conventional weed control programs on the development of weeds, weed control efficiency and yield. The results show that the glyphosate weed control programs compared to the conventional methods decreased not only the number of herbicide applications but equally in magnitude decreased the dosage of active ingredients. The results also showed effective weed control with glyphosate when the weed covering was greater and sugar beets had a later growth stage of four true leaves. Glyphosate-resistant sugar beets applied with the glyphosate herbicide two or three times had an increase in white sugar yield from 4 to 18 % in comparison to the high dosage conventional herbicide systems. In summary, under glyphosate management sugar beets can positively contribute to the increasingly demanding requirements regarding efficient sugar beet cultivation and to the demands by society and politics to reduce the use of chemical plant protection products in the environment.

Summary A new herbicide for sugar beet cultivation using the ALS‐inhibiting active ingredients foramsulfuron and thiencarbazone‐methyl is under approval in the EU member states. Sugar beet genotypes that are non‐sensitive to this herbicide are currently under development. Selectivity of the ALS‐inhibiting herbicide and yield response of the non‐sensitive genotypes might be relevant to meet the requirements for variety registration. To evaluate these issues, six field trials were conducted in Germany in 2013 and 2014. Classic herbicides and the ALS‐inhibitor herbicide were applied in dosages of up to fourfold the authorised (or applied for) application rates. The ALS‐inhibitor herbicide did not cause any significant phytotoxicity and had no effect on leaf area index at a single, double or fourfold dosage. By contrast, classic herbicides had significant negative effects at the single dosage. At fourfold dosage, they caused 41% phytotoxicity and reduced leaf area index by 35%. The relative yield difference between ALS‐inhibitor and classic herbicide treatments was 8.6% and 17.4% of white sugar yield at double and fourfold dosage respectively. The ALS‐inhibitor herbicide thus showed higher selectivity than the classic herbicides. In the registration process, the resulting yield advantage could balance a possible yield penalty of non‐sensitive genotypes. The introduction of a new system for weed control could improve application flexibility and control of troublesome weeds in sugar beet.

KWS SAAT SE and Bayer CropScience AG are jointly developing and commercializing an innovative system of weed control in sugar beet for the global market under the name of CONVISO SMART. The technology is based on the breeding of sugar beet cultivars that are tolerant to herbicides of the ALS-inhibitor-class with a broad-spectrum weed control. This will give farmers a new opportunity to make sugar beet cultivation easier, more flexible in its timing and more efficient. The use of CONVISO, as new herbicide in sugar beet, will make it possible to control major weeds with low dose rates of product and reduced number of applications in the future. The tolerance is based on a change in the enzyme acetholactate synthase, which is involved in the biosynthesis of essential amino acids. This variation can occur spontaneously during cell division. During the development, sugar beets with this spontaneously changed enzyme were specifically selected and used for further breeding of CONVISO SMART cultivars. As such, these varieties are not a product of genetic modification. Field studies with CONVISO SMART hybrids showed complete crop selectivity and a broad and reliable efficacy against a large range of major weeds. The bio-dossier for an EU-wide registration of CONVISO was submitted in April in 2015. The variety inscription process is in preparation in different countries. The system CONVISO SMART is scheduled to be available to farmers in 2018 at the earliest.

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