terclim by ICS banner
IVES 9 IVES Conference Series 9 Yield formation and grape composition: more than meets the eye 

Yield formation and grape composition: more than meets the eye 

Abstract

Fruit quality in grapes is not well defined but is often depicted as correlating inversely with crop yield. Both fruit yield and composition, however, are made from distinct components that interact in complex ways. Reproductive growth of grapevines extends over two growing seasons. Inflorescences initiated in buds during the previous year differentiate flowers and set and develop berries during the harvest year. Compensation mechanisms ensure that changing one yield component typically results in a less than proportional change in yield. For example, reducing the number of berries per vine may increase berry size. Nevertheless, warm temperatures and ample water during budbreak or bloom will increase both the number and size of berries, and increase or decrease berry sugar while decreasing acidity. Moreover, the time of fruit set and the number of seeds, rather than yield, may drive the time of ripening onset. By that time, berry size is effectively predetermined and can no longer be manipulated by cultural practices. Ripening starts with berry softening and is followed by sugar accumulation, acid breakdown and, finally, anthocyanin accumulation in dark-skinned grapes. Like yield components, these processes can be modified by altering the size and density of the canopy, which changes the fruit-zone microclimate. Unlike vegetative and reproductive growth, fruit composition is much more responsive to temperature than to water supply. This presentation will give an overview of yield formation and grape ripening, and discuss some key environmental and viticultural factors that lead to differences in harvest yield and fruit composition.

DOI:

Publication date: June 13, 2024

Issue: Open GPB 2024

Type: Article

Authors

Markus Keller1*
1 Washington State University, Irrigated Agriculture Research and Extension Center, Prosser, WA 99350, USA

Contact the author*

Keywords

grapevine, yield components, water stress, temperature, Vitis

Tags

IVES Conference Series | Open GPB | Open GPB 2024

Citation

Related articles…

Comparison of fortified, sfursat and passito winemaking techniques for the enhancement of the oenological potential of the black grape cultivar Moscato nero d’Acqui (Vitis vinifera L.)

One of the key factors of the economical development of viticulture and wine industry in specific limited areas is the exploitation of ancient, local grape varieties. Therefore, in recent years the growing interest to rediscover minor varieties, previously cultivated, has promoted many studies. With this regard, the focus of this study was the Vitis vinifera L. cultivar Moscato nero d’Acqui, nowadays found only in old vineyards in the Acqui zone (North-West Italy). In particular, the aims of this work were: i) to investigate secondary metabolites profile of the grapes, and ii) to evaluate the attitude to the production of special wines.

HOW DO ROOTSTOCKS AFFECT CABERNET SAUVIGNON AROMATIC EXPRESSION?

Grape quality potential for wine production is strongly influenced by environmental parameters such as climate and agronomic factors such as rootstock. Several studies underline the effect of rootstock on vegetative growth of the scions [1] and on berry composition [2, 3] with an impact on wine quality. Rootstocks are promising agronomic tools for climate change adaptation and in most grape-growing regions the potential diversity of rootstocks is not fully used and only a few genotypes are planted. Little is known about the effect of rootstock genetic variability on the aromatic composition in wines; thus further investigations are needed.

Assyrtiko wines of Santorini produced by different autochthonous yeasts: Differences in aromatic and organoleptic profiles

Different yeasts were isolated from spontaneous fermentation of Assyrtiko grape must in Santorini Island, Greece. Molecular typing revealed the presence of three Saccharomyces cerevisiae strains (S9, S13, S24) and one strain of the yeast species Nakazawaea ishiwadae (N.i). The four isolated strains were further tested in laboratory scale fermentations of Assyrtiko must in pure inoculation cultures and in sequential inoculation (72 hours) of each S. cerevisiae strain with the strain of N. ishiwadae. All fermentation trials were realised in duplicate.

Studying PIWIs in three dimensions: agronomic, economic and ecological evaluation of 14 fungus-tolerant cultivars in Luxembourg

Growing fungus-tolerant cultivars (PIWIs) reduces the need of fungicide use by 50-80 %. PIWIs have the potential to address climate change adaptation and mitigation simultaneously.

Keg wine on tap: a sustainability-oriented innovation

How could the wine industry be more sustainable? To answer this, an Interreg French-Swiss project gathered researchers to help a French keg producer and a Swiss wine distributor make their innovation more ecological, social and economical. What innovation? A reusable plastic keg with a disposable airtight pouch inside.