Technical Yearbook 2024

FIGURE 2. More examples of mutations. Bonnet de Retord (the “striped berry” grape) and Chasselas Cioutat, a leaf shape mutation of Chasselas Blanc.

sources, but are the same cultivar (synonyms). For example, Blaufränkisch was also imported as Blauer Limberger and Limberger, and Sangiovese was also imported as Brunello. The number of scion accessions, though, increases to nearly 1 280, because various cultivar clones are included. For example, 23 Cabernet Sauvignon and 14 Sauvignon Blanc clones are in the genebank. Rootstock accessions are 209. Some rarities and curiosities Some quite unique cultivars originated in South Africa through natural mutations, for example, Cinsaut Gris and Cinsaut Blanc, the colour variants of Cinsaut. Another interesting local colour mutation is Sémillon Rosé (or also called Sémillon Gris), which appeared in Sémillon Blanc vineyards. Sémillon (known then as “Groendruif”) was widely grown, and Prof. Orffer mentioned that 93,7% of plantings were Sémillon in 1822. The “rouge” variant was common in Sémillon vineyards, and Perold mentioned the colour variant “Rooi Groendruif” in his 1926 publication. Another interesting colour mutation is the striped berries of Bonnet de Retord (lighter coloured stripes running from style to pedicel ends of the berry). It is an old black table grape that was known locally as “gestreepte” (striped) berry grape, before Perold identified it correctly. Berry colour mutations are not uncommon in grapevine, but other traits may also be altered, an example of which is the flat, tomato (or pumpkin) berry of “Tamatie Fransdruif” a berry shape mutation of Palomino that is unknown elsewhere. Leaf mutations are also known and many will be familiar with Pinot Meunier, a Pinot Noir mutation with hairy leaves, but probably will not know Chasselas Cioutat, the parsley-leaved grape which is a Chasselas Blanc mutation and planted as a curiosity. The genebank collection is also home to unique accessions from local breeding programmes, like the cultivars and rootstocks from Orffer’s crosses, which include wine grape

cultivars like Chenel, Therona, Nouvelle and Weldra and the US 8-7 rootstock. There are also two wine grape cultivars (Colomino and Follet) from crosses made by P.A.L. Steyn, better known as a deciduous fruit breeder. Research and other activities Over the past few years, accessions in the grape genebank have been DNA fingerprinted and it proved to be a valuable resource to correctly identify some accessions, confirm synonyms (Table 1) or to correct parentages. Examples of misnomers or typing mistakes are two accessions with denominations unknown elsewhere, namely Marlao Seedless and Kostel, correctly identified using DNA fingerprints as Marroo Seedless and Kristal, respectively. Verified and published parentages are also useful to identify accessions correctly. For example, we have a cultivar, Jantar, but there are two cultivars, both named Jantar, one from Bulgaria and the other from Slovenia, and to confuse it even more, there is also a Yantar from Ukraine. All three are white cultivars and have different parentages. With DNA fingerprints we could identify that the Jantar in the ARC collection is the Bulgarian cultivar by confirming the parentage of Queen of the Vineyard and Waltham Cross (Table 2). The fingerprint dataset will in near future be extended to include all markers in the standard set recommended for cultivar identification by the OIV. This will improve comparison with international datasets to identify unknown or wrongly named accessions. Apart from supplying propagation and other material, genebank activities include collection of phenological data. Leaf fall, bud break and flowering dates are collected for 1 278 scion accessions. Wine is made from selected cultivars, and lately, we have been focusing on disease-resistant cultivars, including cultivars recently imported from Germany. Since many of the new, disease-tolerant cultivars

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TECHNICAL YEARBOOK 2024