Rootstock resistance to ToBRFV virus

Resistance to the ToBRFV virus in tomatoes is not only possible through the scion, the upper part of the plant, but also through the rootstock, the lower part that provides the plant's root system. This approach is being explored by Syngenta, a Swiss agribusiness company, which has developed two rootstocks with intermediate resistance to the virus.

Syngenta's new rootstocks

Syngenta has developed two ToBRFV-resistant rootstocks named Fervour and Kronosor. Fervour is primarily intended for small fruit types and also has high resistance to three races of fusarium, a soil-borne fungus. Kronosor is more suitable for larger fruit types, including cluster varieties, old varieties, elongated types, and beef types.

Agronomic performance improvements

According to Hervé Bonich, head of solanaceous product management at Syngenta, after two years of trials, the use of these resistant rootstocks has led to a 2 to 5% increase in yield, depending on the specific segments and varieties of tomatoes tested. This suggests that the rootstocks may offer both disease resistance and improved productivity.

Impact on root system health

To understand the effectiveness of the resistant rootstocks, Syngenta conducted a study comparing sensitive rootstocks Aorta and Kardia with the resistant ones after artificial contamination with ToBRFV. At 21 days post-contamination, the weight of the infected Aorta and Kardia rootstocks was 56% lower than that of the controls. In contrast, the Fervour and Kronosor rootstocks showed no significant loss in root system weight, indicating better resistance to the virus's effects.

Ongoing research and real-world application

The study is continuing to determine if the observed benefits in controlled conditions translate to real-world farming scenarios and whether there is a clear correlation with agronomic performance. Fervour and Kronosor are already established in Belgium and the Netherlands and are now being introduced in France. Syngenta states that these rootstocks are compatible with both its own resistant tomato varieties and other varieties available in the market.