THE VINEYARD & WINERY SHOW
PIWI power
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Fungal resistant hybrid varieties may be the answer to sustainable winemaking, agrochemical reductions, and reducing costs of production – but only if they produce quality wines. Vineyard finds out if the wine world bias against hybrids is starting to wane as interesting, good value PIWI wines emerge. PIWIs are grape varieties that have been bred and selected from Vitis vinifera and non-vinifera parents, to have a high resistance to fungal diseases, as well as other attributes. The name, Piwi is a German abbreviation for Pilzwiderstandsfähig – essentially meaning fungal resistant. Hybrids are far from new and have been grown many years, including in the UK, but the newer varieties now being bred – and their wines – are fast gaining attention, particularly overseas, alongside the push for environmental sustainability. Sam Doncaster is a British-born viticulturist who is involved with Piwi breeding programmes and field selections in Germany with Freytag Nurseries. In Sam’s view, “there are so many reasons why UK wine producers should be considering PIWI vine varieties. We know that V. vinifera is severely challenged to provide good wine grape varieties for the UK climate, overall – so why not look elsewhere? We know that there are restrictions to V. vinifera profitability through
> Sauvignac grown in Pfalz, Germany
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its low yields – so why not look elsewhere? We know that V. vinifera are expensive to grow – so why not look elsewhere? We know that V. vinifera are quite limited in their expression of flavour profile – so why not look elsewhere? And, in all honesty, what red V. vinifera variety consistently, and commercially, gives satisfaction in the UK climate?” The Piwi’s breeding provides natural resistance to fungal diseases, which reduces the need for spraying with agrochemicals, resulting in lower tractor emissions and reduction in compaction – which can only help to encourage better soil health. “There are other advantages also,” explains Sam. “In terms of being fungal resistant, modern breeds might also allow a more secure autumnal period of ripening. This is a simple statement of comparison, where vines that show some resistance to bunch botrytis will always hold a distinct advantage over those that rot easily. “This is not only relevant to the grape clusters, but also for the effectiveness of the leaf, where
these Piwi through other forms of resistance can show better 'quality' of leaf way later into the autumn. Other matters like later bud burst might also be of merit.” Sam added. “I think the UK has only scratched the surface of its own wine making potential,” commented Joel Jorgensen, consultant viticulturist and MD of Veraison. “Many of the Piwis grow well, crop reliably and yield higher than our "traditional" sparkling varieties. I have tasted many fine examples of both still and sparkling wines made in Germany, and the UK, and there is no reason why we can't match or even improve on these. “With climate change, and more conscious consumers, we need to future proof our vineyards and plant varieties that allow us to reduce all our inputs like pesticides, fuel, frost protection and labour,” Joel added.
Research and breeding efforts
Piwi varieties are painstakingly breed interspecific hybrids. “Cross-pollination can
