University of Nebraska
                               Viticulture Program
        
      

 Although most vineyard plantings in the Mid-west are of vines on their
own roots, grafting the desired cultivar onto rootstocks is a standard practice in most
European and California vineyards and in many other parts of the world.  The rootstock
imparts resistance to certain pests, notably phylloxera and nematodes, and may help with
adaptability to soil and other environmental conditions.  This study is part of Mr. Sanjun
Gu’s Ph.D. research and involves the scion cultivar “Gewurztraminer’ grafted onto
several different rootstocks and on its own roots for comparison.  ‘Gewurztraminer’ is
considered marginal for Nebraska conditions, but it is hoped that this study will yield
information that helps with our understanding of environmental adaptability.  Rootstocks
employed include:

                                    Riparia ‘Gloire’ (Vitis riparia)

                                    St. George (V. rupestris)

                                    3309 Couderc (V. riparia x V. rupestris)

                                    110 Richter (V. riparia x V. rupestris)

                                    1103 Paulsen (V. berlandieri x V. riparia)

                                    MG420A (V. berlandieri x V. riparia)

 This study was established in May, 1999 and was repeated at two other Nebraska locations.

In November 2000, half of the vines were mounded with soil to the depth about 20 inches (please see Figure 1.).

 The mounded soil was removed in early May, 2001.

Figure 1. Vines mounded with soil.

Mounding Protects Vines from Cold Winter

As shown in Figure 2&3, mounding can protect vines from cold temperatures. This can be represented by the winter survival, pruning weight, and bud numbers. Here, “bud from old” means buds arose from last year’s shoots, “Total number” means total bud numbers on a vine. “Winter survival” means percentage of vines that had survived from winter. “Old/total” means the

percentage that the new shoots came from last year’s shoots. Mounding has different effects on different rootstocks. Mounded 3309 had the heaviest pruning weight, while own-rooted vines had the lightest (Fig. 4)
Generally, mounding advanced bud-break (Fig. 5), which is not very good because in Nebraska, spring frost can sometimes damage new-burst buds. For some of the  rootstocks, for example, 1103, 420A and 3309, the dates of bud-break were almost the same between mounded and non-mounded vines.

Mounding greatly increased winter survival rate, total number of buds and the number of buds that came from last year’s canes for every rootstock tested (Fig. 6, 7, 8&9).

Rootstocks,  Good or not?

Rootstocks had no obvious effect on pruning weight, but some of them had better winter survival rate and could delay bud break (Fig. 10 &11), for example 420A. It seems that own-rooted vines had the best winter survival, but as we can also see in Fig. 9, most of the buds of own-rooted vines came from underground. In fact, own-rooted vines had the least percentage of buds which arose from last year’s shoots.

Year 2000 vs. 2001

Having suffered a bad winter in 2000-2001 winter, vines performed worse than in the previous winter (Fig. 12 & 13). Some vines were killed.

Some Brief Results

Mounding can protect vines from cold temperature especially in severe winters like last year. Mounding can also advance bud break several days, which varies with rootstock. Different rootstocks responded differently to mounding.

Grafted vines are more easily killed by cold temperatures because the graft union is exposed to open air. However, we cannot conclude that the own-rooted vines are hardier. Better rootstocks in 2000-2001 winter were 3309, Riparia, 110 and 420A.

The InThe Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln.  It is the policy of the University of Nebraska-Lincoln not to discriminate on the basis of gender, age, disability, race, color, religion and marital status, veterans status, national or ethnic origin or sexual orientation.l Resources, University of Nebraska-Lincoln.  It is the policy of the University of Nebraska-Lincoln not to discriminate on the basis of gender, age, disability, race, color, religion and marital status, veterans status, national or ethnic origin or sexual orientation.

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Last modified:  April 8, 2008