Sugar beet : unprecedented virus yellows expression
The CTPS “beets and industrial chicory” Section met on October 15, 2020 in a context of unprecedented virus yellows expression linked to the ban of the use of neonicotinoids in seed treatment and under particularly favorable conditions for aphids vectors of these viruses this year.
Because of this risk of uncontrolled yellows, the future stakes for the official evaluation of varieties for the registration are enormous ; indeed, it will be necessary to continue to be able to evaluate reliably candidate varieties for the multiple characters of interest but also to be able to enhance any varietal progress in tolerance / resistance to yellows or their vectors.
As a reminder, the CTPS “beet and industrial chicory” Section had initiated as early as 2019, in dedicated trials conducted in partnership with the ITB, the evaluation of 3 varieties for which the applicant claimed a good tolerance to beet yellow virus. In 2020, 2 new varieties were also filed with this claim. The trials conducted in 2019 and 2020 have shown their interest and their limits. While they revealed varietal behaviour in relation to the 2 viruses tested out of the 4 present on the plains in 2020, improvements in the experimental system are expected in 2021 (more viruses tested, more experimental sites, etc.). Financial support from the PNRI (National Research and Innovation Plan) has been requested in this respect.
To date, no experimental variety has fully preserved its root and sugar yield in the presence of yellowing. Reducing the impact of yellowing on beet crops will necessarily depend on several factors: tolerant varieties, agronomic practices that reduce aphid pressure, biocontrol, etc.
