Complete: Innovate UK: A novel pre-breeding strategy to reduce dependence on insecticides for virus yellows control in sugar beet

Timescale: 2015 -2020

Project Lead: Dr Lucy James

Project Sponsor: Innovate UK collaboration: ADAS, BBRO

Project Summary

Virus yellows is a major economic disease affecting sugar beet; its impact is particularly significant in the UK due to our maritime climate, and will be exacerbated by potential restrictions on neonicotinoid use and developing insecticide resistance in aphid vectors. Development of genetic resistance is therefore critical to maintain viral control. The consortium has explored the genetic diversity found in beet relatives, identifying candidates exhibiting resistance and tolerance to virus yellows. A novel phenotyping approach has been developed to quantify resistance/tolerance traits, and to identify genes which protect against foliar damage. Using this unique toolkit, tolerance quantitative trait loci (QTL) will be introgressed into modern breeding material, with hybrids assessed for foliar health and yield and new resistant candidates will be characterised, QTL identified, and molecular markers developed for future breeding, ultimately producing new virus-resistant commercial varieties.

Main Objectives

About 10% of yield is lost due to foliar disease (BBRO annual report 2015-16). Good fungicide resistance management is needed to prevent losses and costs increasing. Most beet crops receive one or two fungicide applications, with 80% of treatments using a co-formulation of two modes of action (MoA): azole (de-methylation inhibitor; DMI) and strobilurin (quinone outside inhibitor; QoI) (Garthwaite et al, Fera 2014). Resistance to azole or strobilurin fungicides (e.g. Trkulja et al, Crop Prot. 2015; Vaghefi et al. Plant Dis. 2016) has been reported for Cercospora beticola from other countries in recent years, but the resistance status of UK C. beticola, powdery mildew and rust is not known.

There are now many reports, from a range of crops, of pathogens developing resistance to more than one MoA. This BBRO project is part of a wider levy/industry collaborative project testing new strategies for the management of resistance developing concurrently against two or more MoA, using field experiments and modelling on septoria as a test pathosystem. A review of experimental evidence on resistance management (van den Bosch et al., 2014 Ann. Rev. Phytopath.) showed that good anti-resistance strategies are effective across different pathogens on a range of crops. Results from the collaboration can therefore inform guidance to beet growers.

Latest Report

2020 Final Report

Outcomes / Key Message For Growers And Industry

- Virus yellows resistant or tolerant varieties will play an important role in future ‘Integrated Pest Management’ strategies aimed at reducing the damaging effects of virus yellows on sugar beet crops with few pesticides available to control aphid vectors.
- Virus yellows tolerance QTL have been identified by our research group, which exhibit a significant decrease in canopy yellowing and a yield benefit in the presence of virus.
- Virus yellows resistant and tolerant sugar beet material has been generated which has high potential for development in future breeding programmes.
- This project has significantly accelerated the development of virus yellows resistant and/or tolerant sugar beet varieties for the future.