Selection of GLRaV-3 immune Ramsey

PROJECT TITLE: Selection of GLRaV-3 immune Ramsey

Project leader:  Prof. Gerhard Pietersen (Patho Solutions)

Duration: 1 January 2022 – 31 December 2023

Project Summary:

In previous Winetech funded projects we have shown that grapevine leafroll associated virus type 3 (GLRaV-3) is only detected in some individuals of Vitis rootstock crosses and species commonly used in South Africa. This was tested under conditions where the corresponding scion tested positive for the virus. We have concluded that rootstock crosses, generally made from Vitis species other than Vitis vinifera, have resistance to GLRaV-3 infection but that these crosses are heterogeneous with regards to this trait. Using Ramsey (Vitis champini, formerly Salt creek), we aim to identify GLRaV-3 immune, and GLRaV-3 tolerant individuals of this rootstock, to establish these two phenotypes, make them available to industry and to determine whether genetic differences, based initially on standard molecular markers, exist between those individuals.