The role of rootstocks in the fight against ToBRFV

The Tomato Brown Rugose Fruit Virus (ToBRFV), identified for the first time in 2014, has rapidly spread to many regions of the world, posing a major challenge to tomato production due to its easy transmission.

In recent years, Bayer has conducted numerous trials to better understand the role of rootstocks in the transmission of ToBRFV and the impact of a ToBRFV-resistant rootstock on substrate and soil cultivation.

To understand the role of roots in the transmission of ToBRFV, Bayer carried out several experiments at an independent institute. The roots of the plants were inoculated with ToBRFV. After six weeks, no virus was detected in the leaves, indicating that ToBRFV was not transported from the roots to the shoots of the graft. This result suggests that absorption of the virus by the roots is highly unlikely. This is consistent with other research conducted by independent institutes.

In 2023 and 2024, Bayer continued its research to understand the influence of rootstocks, whether resistant or not to ToBRFV, on the occurrence and level of virus infection and the performance of the graft. To this end, susceptible and resistant rootstocks, as well as susceptible and resistant grafts, have been grafted in all possible combinations.

The results confirmed the initial position that the varieties do not appear to behave differently with the various rootstocks. This is illustrated in the table below.

© Bayer

The results showed practically no symptoms on the leaves or fruits of the resistant grafts, whether they were grafted on susceptible or resistant rootstocks. This research also highlights the importance of the vigor and endurance of the rootstock. Thus, the best performance is achieved by combining a vigorous rootstock with resistant grafts.

In conclusion, to date, our studies indicate that a rootstock resistant to ToBRFV would not play a role in preventing or influencing the resistance of the grafted variety. The resistance of the grafted variety is decisive. Furthermore, our research also confirms the importance of the vigor and endurance of the rootstock, which provide a solid foundation to ensure better production.

Growers are invited to watch this video that summarizes all the results of the trials conducted by Bayer on rootstocks and ToBRFV: Does rootstock choice affect ToBRFV resistance?