title: Management practices impact vine carbohydrate status to a greater extent than vine productivity.
abstract: Light pruning and deficit irrigation regimes are practices which are widely used in high yielding commercial vineyards in the warm climate regions of Australia. Little information is available on their impacts on carbohydrate dynamics in vegetative organs within and between seasons, and on the resulting plant capacity to maintain productivity and ripen fruits. This study was conducted to address this gap in knowledge over five vintages on Vitis vinifera L. cv. Cabernet Franc, Shiraz, and Cabernet Sauvignon in the Sunraysia region of Victoria, Australia. Lighter pruning did not change the total carbohydrates concentration and composition in wood and roots within seasons in Cabernet Franc and Shiraz. However, the total carbohydrate pool (starch and soluble sugars) at the end of dormancy increased under lighter pruning, due to higher vine size, associated with retention and growth of old-wood (trunk and cordons). Water deficit negatively impacted trunk and leaf starch concentrations, over the day and within seasons in Cabernet Sauvignon. Soluble sugars concentrations in these tissues tended to be higher under limited water supply, possibly due to higher sugar mobilization as photosynthesis decreased. Trunk carbohydrate concentrations markedly varied within and between seasons, highlighting the importance of interactive factors such as crop load and climate on carbon status. The period between fruit-set and véraison was shown to be critical for its impact on the balance between carbon accretion and depletion, especially under water deficit. The lower leaf and trunk starch concentration under water deficit resulted in a decrease of yield components at harvest, while similar yields were reached for all pruning systems. The sugar allocated to berries at harvest remained remarkably stable for all practices and seasons, irrespective of vine yield and carbohydrate status in vegetative organs in Shiraz and Cabernet Sauvignon.
authors.affiliation: CSIRO Plant Industry Glen Osmond, SA, Australia ; Montpellier SupAgro, UMR LEPSE Montpellier, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Pellegrino
authors.affiliation: CSIRO Plant Industry Glen Osmond, SA, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Clingeleffer
authors.affiliation: CSIRO Plant Industry Glen Osmond, SA, Australia ; Higher Education - Primary Industries, Northern Melbourne Institute of TAFE Melbourne, VIC, Australia.
authors.forename: Nicola
authors.initials: N
authors.lastname: Cooley
authors.affiliation: CSIRO Plant Industry Glen Osmond, SA, Australia.
authors.forename: Rob
authors.initials: R
authors.lastname: Walker
keywords: carbohydrates; deficit irrigation; grapevine; pruning; variety; vine physiology