Vine Germplasm: Rootstocks
VINE GERMPLASM: ROOTSTOCK
4. Minor vine rootstocks
The three most important and cultivated rootstocks, Kober 5 BB, 1103 Paulsen and 110 Richter, making up 80% used in the production of grafted rootlings, leave only 20% to the other numerous remaining ones. They are for viticulture with particular limits such as high levels of active limestone (41 B), the need for less vigour or particular soil and climate requirements. The nurseryman’s solution to such requirements envisages the use of other hybrids:
› Vitis berlandieri x Vitis riparia
S.O.4 and BINOVA: rootstocks with over 320 ha in fields of mother plants, mainly for export. They are not requested much now by Italian vine-growers, due to the dimorphism above mentioned and also for their characteristic poor absorption of magnesium. For this reason, if they are used together with some varieties such as Cabernet Sauvignon and Trebbiano Toscano, they favour the incidence of Bunch Stem Necrosis.
420 A: a rootstock used in the past for canopy-fruit balance, today fallen into disuse because of its susceptibility to Agrobacterium Vitis present in replanted vineyards.
161.49 C and 157.11 C: rootstocks sometimes confused with each other, today used as an alternative to 420 A as they endure replanting well, or for particular areas in southern Italy (Apulia), because of their fair resistance to levels of limestone and drought.
› Vitis riparia x Vitis rupestris: used for densely-planted vineyards requiring low plant vigour, and for some varieties in viticulture of excellence, such as Collio, for some varieties. Their limitations are poor resistance to asphyxiation and iron chlorosis. They are rootstocks currently in evident decline.
› Other hybrids: is requested only 41 B (cv Chasselas x Berlandieri) requested, although in limited quantities, especially in the Verona area; it is suitable for dolomitic soils and quality wines (Amarone).