Temperatures during flowering in 2019 determine 2020 crop yields

Wednesday June 10 2020 by Vitisphere

For vine flowering, there is a critical 2-week period.For vine flowering, there is a critical 2-week period. - Photo credit : Pixabay

For years, research has on various occasions shown a connection between a given climatic factor, such as temperature or rainfall, and key development stages in the vine’s growth cycle. This was demonstrated once again in 2017, when researchers showed that cool temperatures at budburst increased the number of flowers per inflorescence.

But so far, no-one had successfully explained the impact of the climate as a whole, during an entire vintage, on yield. A joint project by the New Zealand Institute for Plant & Food Research, Montpellier Supagro and INRAE has achieved just that.

A mammoth task

As part of the project, researchers monitored Sauvignon planted on four estates in the Malborough region for 15 years. “We wanted answers to 3 questions”, they explain in their paper. “What are the correlations between each yield component and different weather factors? Is there a dominant weather factor (maximum temperatures, rainfall...)? What are the critical periods that determine each yield component?”

On each estate, they selected 8 replicate plots of 4 vines, asking the winegrowers to farm them as they did the rest of their estate. From 2004 to 2019, they examined weather data retrieved from nearby weather stations. On each vine, they counted the number of bunches and berries and weighed them, taking care to eliminate those that had too much botrytis infection.

Their conclusion leaves no room for doubt. According to their mathematical model, the daily maximum temperatures recorded before full bloom in the previous year alone determine more than 50% of the current year's yield.





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mike mosesian 10 june 2020 - 18:25:51
what are the max and min temps that are most significant before bloom to increase fruitfulness of the buds for the following year? I grow wine grapes in greenhouses in Alaska and many vines are unfruitful, therefore, I want to know more about what temps and vigor of vine during bloom most effects fruitfulness for following year. I grow only vinifera vines and winter temps inside do not go below 20F. I can prune all vines so as to obtain more fruit . Thanks Mike
Dona 11 june 2020 - 17:26:58
Please could you send me a copy of this study too please? Very interesting! Many thanks!
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