Comparison of the effects of rootstock on crop, juice and wine composition in a replanted nematode-infested Barossa Valley vineyard

Abstract

Shiraz grapevine scions grafted to Ramsey, Dog Ridge, Harmony, Schwarzmann and 1613 rootstocks outyielded Shiraz on their own roots in a replanted, nematode-infested vineyard in the Barossa Valley. The cultivar Ramsey gave the largest cumulative yield (44 kg/vine) over three years in comparison with 16 kg/vine for own-rooted vines. The observed yield increases could be attributed to both more bunches per vine and increased bunch weight. Juice from the fruit of ungrafted vines had lower pH than that from rootstocks. Wine made from this juice had higher colour density and ionized anthocyanins and the lowest wine colour hue. The ranked performance of individual rootstocks was not consistent from season to season as shown by significant rootstock x year interactions for 15 of 20 variables measured.