Table grape rootstocks in South Africa

Affinity Table 3 provides information on the compatibility of various graft combinations of table grape scion cultivars and different rootstocks. This was compiled from reports of ARC Infruitec-Nietvoorbij investigations of plant material, as received from producers (from established vineyards) over the past few seasons. The results indicate that poor affinity occurs with several rootstocks and scion cultivars. If information regarding specific clones of these graft combinations were available; it might have been possible to determine whether there is a correlation between clone compatibility and poor affinity. This would have assisted in predicting potential affinity problems between scion-rootstock combinations.

The information compiled for Table 3 suggests that Ramsey has affinity problems with several scion cultivars. It is generally assumed that R 99 has a good affinity with most scion cultivars. From this investigation, it was clear that the degree of affinity problems differed from one season to the next and that the graft technique used also influenced the results. Problems regarding affinity were more pronounced when using the omega grafting technique (Figure 11). This observation should probably be attributed to the graft technique used and not the poor physiological interaction between scion cultivar and rootstock.

TABLE 3. Affinity problems of different scion and rootstock combinations of table grapes (results recorded for plant material examined by ARC Infruitec Nietvoorbij).

ROOTSTOCK

R 110

143 B Mgt

P 1103

Ramsey

US 8-7

Early Sweet TM Sugranineteen Sugrathirtyfour

Sugrathirtyfour

Sugranineteen Sugrasixteen Sugranineteen Sugrathirtyfour

Arrafifteen®

Sugrathirtyfour

Crimson Seedless

LaRochelle Redglobe Sugrasixteen

Sugranineteen Sugrathirtyfour Sugrathirtyfive Tawny Seedless®

Source: Abraham Vermeulen, Diagnostic Services, ARC Infruitec-Nietvoorbij

How could compatibility and affinity problems be prevented? • Using plant material that is free of harmful viruses. • Using the best grafting technique and the best scion-rootstock combination. • Identifying the best scion-rootstock combinations can be done by grafting new cultivars onto different rootstocks

and establishing them in field trials and/or commercial vineyards. • Planting only certified vines obtained from registered nurseries.

22 Table Grape Rootstocks in South Africa