Crop load management of newly planted Pinot gris grown in warm climate of California

Context and purpose of the study ‐ An advancement of grapevine phenological development has been observed worldwide in the last two decades. In South Australia this phenomenon is even more accentuated since grapevine is often grown in a hot climate. The main consequences are earlier harvests at higher sugar levels which also result in more alcoholic wines. These are deemed undesirable for the Australian wine industry with consumer preferences shifting towards lower alcohol wines. Vineyard practices can be implemented to control and delay ripening. Amongst them, apical late leaf removal has been successfully applied in Europe to delay ripening by up to two weeks in Sangiovese, Aglianico and Riesling. In those studies, no negative effects were observed on grape colour, phenolics and on the carbohydrate storage capacity of the vines. To date, this technique has not been studied in Australia. In this study late leaf removal, apical to the bunch zone was applied to the variety Semillon for four seasons and compared to an untreated control.

The Occitanie Region is the first vine-growing area in France: 270 000 hectares of vineyard and an annual production of 15 million hectoliters. Its annual income reaches 1 900 million euros, of which 900 million euros in export.The vine and wine sector is facing many issues: inputs reduction, adaptation to climate change, maintaining the production competitiveness, digital tools integration in production and transformation processes, and the production of quality wines meeting the consumer demand.

Grapevine, Vitis vinifera, requires grafting on Phylloxera tolerant rootstocks of American origin in most viticultural areas of the world. The most commonly used species in rootstock creation are V. berlandieri, V. riparia and V. rupestris. Rootstocks not only provide tolerance to Phylloxera but assure the supply of water and mineral nutrients to the scion. The objective of this work was to determine to what extent rootstocks of different parentages alter the mineral composition of petioles of grapevine.

Plants have been shown to redistribute water between root sections and soil layers along a gradient of decreasing water availability. One benefit of this hydraulic redistribution is that water can be transported from roots in wet soil to others in dry soil, delaying the onset of water stress and increasing root longevity in dry environments. Grapevines are thought to redistribute water laterally across the trunk from wet to dry portions of the root system. However, it is unknown whether the phloem contributes to such water redistribution.

Context and purpose of the study – The dormant and growing season temperatures in California USA have been increasing with more clear sky days. A consequence increasing temperatures and clear sky days is water deficit conditions. Viticulturists must determine appropriate balances of canopy management and irrigation budgeting to produce suitable yields without compromising berry chemistry. In response, a study designed to test the interactive effects of leaf removal timing and applied water amounts on Cabernet Sauvignon/110R in Napa Valley, CA.