Abstract
Grapevine phenology is continuously advancing due to global warming, exposing berry ripening to increasingly drier and hotter episodes that can dramatically affect yield and berry quality. This study aimed to analyse whether intermittent shading produced by panels placed over the plants can delay berry ripening to counter the impact of global warning on phenology. A two-year outdoor trial repeated on two batches of young potted grapevine (cv. Syrah) was conducted in Montpellier (South of France). Shading was created in a row using 2 m-wide horizontal panels placed 2.4 m above the ground. A moderate water deficit was also applied at the start of veraison to half the plants in both full sun (without panels) and shaded conditions to mimic usual field conditions. Variables related to budburst, flowering, veraison and sugar at harvest were analysed in all treatments. Although intermittent shading did not significantly modify air temperature within the canopy when cumulated over the growing season, the panels substantially delayed veraison by up to more than 30 days under well-watered conditions. The most marked phenological shifts were noted in the second year of treatment between flowering and veraison when carbon demand sharply increased during berry formation, suggesting there was a carry-over effect likely due to limited carbon assimilation. This was accompanied by sharp decreases in berry diameter and sugar content per berry at harvest. Higher berry growth and sugar loading were maintained when shading was combined with water deficit. However, the trigger effect of water deficit on veraison almost halved the phenological delay caused by the panels. Overall, a cooler period for ripening could be achieved with panels over the vines but at the expense of berry size and sugar amount in berries. It can be concluded that shading intensity and duration should be adapted to evaporative and soil water conditions to benefit from the phenological delay caused by panels, without altering production in the long term.
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Claims 9
Claim · model-written summary
Intermittent shading did not significantly change cumulative canopy air temperature.
- Treatment
- intermittent shadinge0
- Outcome
- air temperature within the canopye0
- Direction
- did not significantly modifye0
VitisNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“intermittent shading did not significantly modify air temperature within the canopy when cumulated over the growing season”
t0“young potted grapevine (cv. Syrah)”
Claim · model-written summary
Panels delayed veraison more than 30 days under well-watered conditions.
- Treatment
- panelse0
- Outcome
- veraisone0
- Direction
- delayede0
- Value
- more than 30 dayse0
- Qualifier
- well-watered conditionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the panels substantially delayed veraison by up to more than 30 days under well-watered conditions”
t0“young potted grapevine (cv. Syrah)”
Claim · model-written summary
Phenological shifts were greatest in the second year between flowering and veraison.
- Outcome
- phenological shiftse0
- Direction
- most markede0
- Qualifier
- second year of treatment between flowering and veraisone0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The most marked phenological shifts were noted in the second year of treatment between flowering and veraison”
t0“young potted grapevine (cv. Syrah)”
Claim · model-written summary
Shading decreased berry diameter.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This was accompanied by sharp decreases in berry diameter and sugar content per berry at harvest”
t0“young potted grapevine (cv. Syrah)”
e1“intermittent shading produced by panels placed over the plants”
Claim · model-written summary
Shading decreased sugar content per berry at harvest.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This was accompanied by sharp decreases in berry diameter and sugar content per berry at harvest”
t0“young potted grapevine (cv. Syrah)”
e1“intermittent shading produced by panels placed over the plants”
Claim · model-written summary
With water deficit, shading maintained higher berry growth and sugar loading.
- Treatment
- shading was combined with water deficite0
- Outcome
- berry growth and sugar loadinge0
- Direction
- Highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Higher berry growth and sugar loading were maintained when shading was combined with water deficit”
t0“young potted grapevine (cv. Syrah)”
Claim · model-written summary
Water deficit almost halved the panel-induced delay in veraison.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the trigger effect of water deficit on veraison almost halved the phenological delay caused by the panels”
t0“young potted grapevine (cv. Syrah)”
Claim · model-written summary
Panel use could achieve a cooler ripening period.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a cooler period for ripening could be achieved with panels over the vines”
t0“young potted grapevine (cv. Syrah)”
Claim · model-written summary
The authors recommend adapting shading intensity and duration to water conditions.
- Outcome
- shading intensity and duration should be adapted to evaporative and soil water conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shading intensity and duration should be adapted to evaporative and soil water conditions”
t0“young potted grapevine (cv. Syrah)”
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