A Guide to Grapevine Abnormalities in South Africa - P.G. GOUSSARD

together with normal, seeded berries in individual bunches (Photos 447 - 449), care should be taken not to assess such phenomena without further ado as being representative of aberrations in this category. Based on the fact that incidences of millerandage may be ascribed to various and widely divergent causes/factors, it is strongly recommended that confirmation be sought by means of subsequent investigations/observations. Bunch size and shape Aberrations also occur where bunch sizes and shapes differ from the normal situation(s). A well-known example in this regard is “knoptros” or Le Roux-Hanepoot, in which case bunches are fairly small, with few exceptions. Obviously the yields from such aberrations are usually considerably lower, compared to that of normal grapevines. Berry shape In this regard one can single out Muscat d’Alexandrie as one of the best-known cultivar examples as far as various berry shape aberrations are concerned. Examples are still being cultivated locally and known as: (i) long berry Hanepoot; (ii) round berry Hanepoot and (iii) pear-shaped Hanepoot. An aberration that may be propagated vegetatively has also occurred in Palomino, in which case the berries are clearly segmented in appearance (Photo 450). Known locally as ‘Tamatie-Frans’, it often attracts a lot of attention because it is so interesting. Berry colour Based on white, red, grey and black as being representative of the four main colours encountered among ripe grapes, mutations in this category are probably best known, since they are easy to recognise. In South Africa some of the best known examples of colour aberrations from white to red are Red Hanepoot and Red Sémillon. Although not a local phenomenon, Red Muskadel entered the world of viticulture in the same way, namely as an aberration of White Muskadel. A phenomenon that is probably most prevalent is where a grapevine has only one shoot bearing red grapes, or even just a single red bunch. Instances have also occurred where an individual bunch, or only a part thereof, or even just a few berries, have undergone discolouration (Photos 451 - 453). Experts in this field maintain that colour changes occur in sequence from black – red or grey – white (or the other way around), but not directly from black to white or from white to black. As far as could be ascertained, the local industry has not seen any individual cultivar(s) changing from black – red – white. Having said that, a colour change has occurred from black to grey to white, notably in the case of Cinsaut noir (Photos 454 & 455). Other examples from further afield

284 • A Guide to Grapevine Abnormalities in South Africa