Technical Yearbook 2024

Lime-rich soils 140 Ruggeri is theoretically the champion on dry, saline lime-rich soils. Poor propagation and grafting problems at nurseries have resulted in the rootstock losing much of its popularity in South Africa. It was found that the Richters, especially 99 Richter, performed just as well on lime soils, provided that the soils are not saline or poorly drained. The other option, especially where wetness occurs in the subsoil (without the danger of salinity) is 1103 Paulsen . This rootstock’s vigour is between that of 99 Richter and 110 Richter. 1103 Paulsen offers poor resistance against Phytophthora (just like 99 Richter), which has caused its popularity to wane in South Africa.

Red, well-drained soils The Richters (99 and 110) are well adapted to these soils. 99 Richter is better for high yields under irrigation, while 110 Richter is more suited to slightly lower yields and instances where irrigation water can pose a problem. The Richters do not perform well with subsoil wetness or on saline soils, but offer good drought resistance. 99 Richter is very sensitive to Phytophthora which occurs naturally in soils under fynbos and pine trees. If the soil potential is very high, in combination with strong-growing cultivars like Cabernet Sauvignon or Shiraz, a rootstock like 101-14 Mgt can be chosen to keep vigour in check for a higher-quality wine goal. Lower-potential, wet and poorly drained soils under natural fynbos 8-7 USVIT with an exceptional to very strong vigour, good wetness resistance and very good resistance against Phytophthora is ideal for this type of soil, especially in cooler areas where higher yields and early ripening are desired. 143 B , which is not so widely available in the wine industry anymore, will also perform well on these soils. This rootstock has a very low resistance against phylloxera. It is mostly used on the silt rich river soils of the Orange River for raisins under flood irrigation.

Conclusion A great number of variables must be considered in the choice of rootstocks and it is important that the soil scientist, viticulturist and winemaker consult on this decision together. In light of the strong environmental influence on rootstock performance and continuous change in market requirements, rootstock characteristics (as seen in Table 1), should be reviewed and updated regularly as new choice will play a crucial role in the future to buffer vineyards against the impact of climate change. Rootstock research, and in particular new breeding programmes to establish new rootstock options, should enjoy priority.  information becomes available. Rootstock

Reference https://www.wineland.co.za/suitable-rootstock-for-soil-and-wine-goal/

For more information, contact Heinrich Schloms at heinrich@vinpro.co.za.

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TECHNICAL YEARBOOK 2024