SATI Beyond The Bunch 2nd Quarter 2026

Phase 2

had among the highest values for bunches per vine and bunch and berry mass. No other rootstock had among the highest values for all three of these traits. Yarona The rootstocks had similar yields at Yarona, again with the exception of the lower-yielding GRN-2 and GRN-4 (compared to the top-performing Ramsey and Kingfisher). Ramsey and Minotaur had among the highest values for bunches per vine and berry mass. First impressions When considering performance across all sites, the top yielding rootstocks were Kingfisher, Minotaur, and Ramsey. Of these, Minotaur was significantly more vigorous and had a higher scion:rootstock diameter than Ramsey, but not than Kingfisher. At both JDK and Yarona, Freedom had high TSS, high titratable acidity (TTA), and low TSS:TTA. During ripening, it appears that its acids decline slowly relative to its sugars. So far, Ramsey, Kingfisher, and Minotaur show the most promise in phase 2, but keep in mind that several years of data still need to be collected and analysed.

As already mentioned, phase 2 includes Freedom, GRN-2, GRN-4, Kingfisher, Minotaur, Paulsen 1103, and Ramsey. Note that GRN-2, GRN-4, Kingfisher, and Minotaur are not yet officially registered in South Africa. Phase 2 is planted at three sites (JDK, Excelsior, and Yarona). Site and scion details are given in Table 2. Since this phase was only established in 2022, the first harvest at JDK and Yarona was in 2024, and at Excelsior in 2025. The summary that follows is based on the 2025–2026 season. Note that trials will continue At Excelsior, the only traits that differed significantly between rootstocks were scion:rootstock diameter, earliness of bud break, and total soluble solids (TSS). No rootstock had among the top values for all three traits. Minotaur showed potential compatibility and vigour problems at this site. JDK All the rootstocks had similar yields at JDK, except for GRN-2 and GRN-4, which had lower yields than the top performers (Ramsey and Minotaur). Ramsey also until 2028. Excelsior

Table 2. Site and trial characteristics for phase 2 (2022–2028). Excelsior

JDK

Yarona

De Doorns Hex River

Paarl Berg River

Kanoneiland Orange River

Location

Scion cultivar Vine spacing

Crimson Seedless

Sugrathirtyfive

IFG Ten

3.0 x 1.8 m

3.0 x 1.8 m

3.3 x 1.6 m

0–30 cm 30–60 cm General

Sand Sand

Loam Loam pH 5.9

Loam Loam pH 6.8

Soil

pH 6.1

Irrigation system

Micro-sprinklers

Drip

Micro-sprinklers

Trellis system

Gable

Gable

Gable

KEBO TOOLO | PROVAR

BEYOND THE BUNCH • 12 • QUARTER 2 • 2026