Grapevine Sugar Concentration Model (GSCM): A Decision Support Tool for the Douro Superior Winemaking Region

Round 1

Reviewer 1 Report

Dear Author,

 The article it is well structured and all key elements are present.

The title clearly describes the article.

The abstract content clearly reflects the entire content of the article.

In the introduction paragraph the authors clearly present the problem investigated. Also, the purpose of the study is specified.

The methods used are scientifically appropriate and well described.

Results are clearly presented and discussed.

Conclusions are supported by the results and are reasonable.

References are appropriate.

Although, there is a small remark: on paper I would suggest using less

abbreviations for the different parameters analyzed and also the use of more concise table titles.

The article has an interesting view of the data that can be used in a model for grape sugar concentration, a model that can be used for forecasting harvest data in many vineyards.

Thank you!

Author Response

Reviewer #1

Dear Author,

 The article it is well structured and all key elements are present.

The title clearly describes the article.

The abstract content clearly reflects the entire content of the article.

In the introduction paragraph the authors clearly present the problem investigated. Also, the purpose of the study is specified.

The methods used are scientifically appropriate and well described.

Results are clearly presented and discussed.

Conclusions are supported by the results and are reasonable.

References are appropriate.

Although, there is a small remark: on paper I would suggest using less abbreviations for the different parameters analyzed and also the use of more concise table titles.

The article has an interesting view of the data that can be used in a model for grape sugar concentration, a model that can be used for forecasting harvest data in many vineyards.

Thank you!

Reply: We would like to thank the Reviewer for his/her comments, which have contributed to improve our study. In particular, we have removed some unnecessary abbreviations from the manuscript.

Reviewer 2 Report

Check ALL figure captions and table captions for consistency and detailed information to understand the figure. Present the information in the caption the same in all figure captions. In Figure 6, the secondary axis is mentioned before the primary axis but the axis information is included. No other figure captions included axis information (consistency).

Line 21

add à the Association for the Development of Viticulture in the Douro Region (ADVID)

 Line 76

Check font size à Suter et al.

Line 103

Should the reference be Figure 1 instead of Figure 1a?

Line 110

Should the reference be Figure 1a instead of Figure 1?

Line 111

Replace variety with cultivar; cultivar was used and introduced in the abstract.

Line 130

…different solar exposure…where is the dataset for solar exposure?

Figure 1.

The quality of the hypsometric chart needs to be improved, appears blurry.  What do the colors represent in Figure 1a and 1b?  What is the difference between the two charts? 

Table 1.

Clarification needed: Nyear is defined as the annual mean number of observations. Is this for temperature and precipitation totals per actual site? i.e. there were only 5 observations taken at the actual site, per year for TN1, 3 for TN2, 3 for TN3, 4 for TF1, and 3 for TF2?

Figure 2.

Suggestion: add key to the right of the diagram (precipitation = bars; temperature = line)

Line 165

Where is the grapevine phenological data presented? Was the data previously published? How many sample dates, how many samples per site, when was it sampled, etc.?

Line 172

Where is the data on berry quality? Is this referencing methods or is this the data? If this is the dataset, then specify previously published.

Line 188

Same as above, is this referencing how the data was collected (ie similar to or as previously described by xxx) or is the presented in the referenced article the data that was used to make the computer model?

Line 228 and 239

Replace thermal forcing with Forc (Forc was defined in Line 225)

Line 243

Replace varieties with cultivars

Line 246

Replace variety with cultivar

Line 303

Replace variety with cultivar

Line 397

Replace varieties with cultivars

Check ALL figure captions and table captions for consistency and detailed information to understand the figure. Present the information in the caption the same in all figure captions. In Figure 6, the secondary axis is mentioned before the primary axis but the axis information is included. No other figure captions included axis information (consistency).

Line 21

add à the Association for the Development of Viticulture in the Douro Region (ADVID)

Line 76

Check font size à Suter et al.

Line 103

Should the reference be Figure 1 instead of Figure 1a?

Line 110

Should the reference be Figure 1a instead of Figure 1?

Line 111

Replace variety with cultivar; cultivar was used and introduced in the abstract.

Line 130

…different solar exposure…where is the dataset for solar exposure?

Figure 1.

The quality of the hypsometric chart needs to be improved, appears blurry.  What do the colors represent in Figure 1a and 1b?  What is the difference between the two charts? 

Table 1.

Clarification needed: Nyear is defined as the annual mean number of observations. Is this for temperature and precipitation totals per actual site? i.e. there were only 5 observations taken at the actual site, per year for TN1, 3 for TN2, 3 for TN3, 4 for TF1, and 3 for TF2?

Figure 2.

Suggestion: add key to the right of the diagram (precipitation = bars; temperature = line)

Line 165

Where is the grapevine phenological data presented? Was the data previously published? How many sample dates, how many samples per site, when was it sampled, etc.?

Line 172

Where is the data on berry quality? Is this referencing methods or is this the data used to create the models? If this is the dataset, then specify previously published. If it is referencing the methodology, please reword to make this clear. 

Line 188

Same as above, is this referencing how the data was collected (ie similar to or as previously described by xxx) or is the data in the referenced article the data that was used to make the computer model?

Line 228 and 239

Replace thermal forcing with Forc (Forc was defined in Line 225)

Line 243

Replace varieties with cultivars

Line 246

Replace variety with cultivar

Line 303

Replace variety with cultivar

Line 397

Replace varieties with cultivars

Overall I think the model could be useful to growers but clarification/more information on the data used to create the models needs to be included in the manuscript. If the data used is from previous studies (published data) then state this. Otherwise, how many samples per site, collection frequency, etc.

Consider adding a map of the location of the climate stations (CS3) in relation to the vineyards.   

Author Response

Reviewer #2

Check ALL figure captions and table captions for consistency and detailed information to understand the figure. Present the information in the caption the same in all figure captions. In Figure 6, the secondary axis is mentioned before the primary axis but the axis information is included. No other figure captions included axis information (consistency).

Reply: We would like to thank the Reviewer for his/her comments, which have contributed to improve our study.

In particular, we have reviewed all the figure/table caption, also taking into account another reviewer suggestion.

The point-by-point replies are provided below and highlighted in blue font, as well as the corresponding changes in the manuscript

Line 21 add à the Association for the Development of Viticulture in the Douro Region (ADVID)

Reply: Done.

 Line 76 Check font size à Suter et al.

Reply: Done

Line 103 Should the reference be Figure 1 instead of Figure 1a?

Reply: Done

Line 110 Should the reference be Figure 1a instead of Figure 1?

Reply: Done

 Line 111 Replace variety with cultivar; cultivar was used and introduced in the abstract.

Reply: Done

Line 130 …different solar exposure…where is the dataset for solar exposure?

Reply: Removed

Figure 1. The quality of the hypsometric chart needs to be improved, appears blurry.  What do the colors represent in Figure 1a and 1b?  What is the difference between the two charts?

Reply: We have uploaded a higher resolution figure, which shows Fig 1a. Elevation, Fig 1b temperature.

Table 1. Clarification needed: Nyear is defined as the annual mean number of observations. Is this for temperature and precipitation totals per actual site? i.e. there were only 5 observations taken at the actual site, per year for TN1, 3 for TN2, 3 for TN3, 4 for TF1, and 3 for TF2?

Reply: Nyear was removed to avoid confusion, the total number of observations ranges from 17 to 33, corresponding to the Ntot the Table 1.

Figure 2. Suggestion: add key to the right of the diagram (precipitation = bars; temperature = line)

Reply: Done.

Line 165 Where is the grapevine phenological data presented? Was the data previously published? How many sample dates, how many samples per site, when was it sampled, etc.?

Reply: The raw phenological datasets are intellectual property of the private companies, and therefore are not open access. The samples corresponds to the Ntot.

Line 172 Where is the data on berry quality? Is this referencing methods or is this the data? If this is the dataset, then specify previously published.

Reply: This data is also intellectual property of the companies and thus is not publicly available.

Line 188 Same as above, is this referencing how the data was collected (ie similar to or as previously described by xxx) or is the presented in the referenced article the data that was used to make the computer model?

Reply: This is referencing the method used to collect the data.

Line 228 and 239 Replace thermal forcing with Forc (Forc was defined in Line 225)

Reply: Done.

Line 243 Replace varieties with cultivars

Reply: Done.

Line 246 Replace variety with cultivar

Reply: Done.

Line 303 Replace variety with cultivar

Reply: Done.

Line 397 Replace varieties with cultivars

Reply: Done.

Overall I think the model could be useful to growers but clarification/more information on the data used to create the models needs to be included in the manuscript. If the data used is from previous studies (published data) then state this. Otherwise, how many samples per site, collection frequency, etc.

Reply: We have added the following sentence:

“For grape berry ripening monitoring, field samplings of 200 berries from each estate, randomly collected from the different pre-defined reference plots, were taken [31]. Data collection frequency usually ranged from 5 to 10 days.”

Regarding data availability, please see reply above about data intellectual property.

Consider adding a map of the location of the climate stations (CS3) in relation to the vineyards.

Reply: The map containing the temperature data is shown in figure 1b.

Reviewer 3 Report

The authors developed a modeling tool to assess the sugar concentration levels in the “Douro Superior” sub-region, Portugal studying two main cultivars (cv. Touriga-Nacional and Touriga-Francesa). Grape berry sugar data, with concentrations between 170 and 230 g L-1, were analyzed for the growing season campaigns, from 2014 to 2020, as an indicator of grape ripeness conditioned by temperature factors.

Lines 39-41. Add the following sentence: “New climate conditions are affecting viticulture and the winemaking sector worldwide [1,2], modifying this crop spatial distribution [3], development timings [4], agronomic techniques [5-6], and altering yields and quality [7]”.

[5] Verdenal, T., Zufferey, V., Dienes-Nagy, A., Bourdin, G., Gindro, K., Viret, O., & Spring, J. L. (2019). Timing and intensity of grapevine defoliation: an extensive overview on five cultivars in Switzerland. American Journal of Enology and Viticulture, 70(4), 427-434.

[6] Cataldo, E., Salvi, L., Paoli, F., Fucile, M., & Mattii, G. B. (2021). Effects of defoliation at fruit Set on vine physiology and berry composition in cabernet sauvignon grapevines. Plants, 10(6), 1183.

Lines 45-46 Please, rewrite “one of the key aspects of viticulture, is indeed strongly tied to the heat accumulation conditions at each site”

Lines 45 Add the following sentence “In effect, air temperature is considered the main forcing factor of grapevine phenology [8,9], harvest timings, solid soluble, and aroma concentration [10-11]”.

[10] Cataldo, E., Fucile, M., & Mattii, G. B. (2022). Effects of Kaolin and Shading Net on the Ecophysiology and Berry Composition of Sauvignon Blanc Grapevines. Agriculture, 12(4), 491.

[11] Leng, F., Wang, C., Sun, L., Li, P., Cao, J., Wang, Y., ... & Sun, C. (2022). Effects of Different Treatments on Physicochemical Characteristics of ‘Kyoho’Grapes during Storage at Low Temperature. Horticulturae, 8(2), 94.

Line 56 “The sigmoid model” briefly explain

Authors should replace DOYs with standard days for easier reading (graphics and text)

Author Response

Reviewer #3

The authors developed a modeling tool to assess the sugar concentration levels in the “Douro Superior” sub-region, Portugal studying two main cultivars (cv. Touriga-Nacional and Touriga-Francesa). Grape berry sugar data, with concentrations between 170 and 230 g L-1, were analyzed for the growing season campaigns, from 2014 to 2020, as an indicator of grape ripeness conditioned by temperature factors.

Reply: We would like to thank the Reviewer for his/her comments, which have contributed to improve our study. The point-by-point replies are provided below and highlighted in blue font, as well as the corresponding changes in the manuscript

 Lines 39-41. Add the following sentence: “New climate conditions are affecting viticulture and the winemaking sector worldwide [1,2], modifying this crop spatial distribution [3], development timings [4], agronomic techniques [5-6], and altering yields and quality [7]”.

[5] Verdenal, T., Zufferey, V., Dienes-Nagy, A., Bourdin, G., Gindro, K., Viret, O., & Spring, J. L. (2019). Timing and intensity of grapevine defoliation: an extensive overview on five cultivars in Switzerland. American Journal of Enology and Viticulture, 70(4), 427-434.

[6] Cataldo, E., Salvi, L., Paoli, F., Fucile, M., & Mattii, G. B. (2021). Effects of defoliation at fruit Set on vine physiology and berry composition in cabernet sauvignon grapevines. Plants, 10(6), 1183.

Reply: Done.

Lines 45-46 Please, rewrite “one of the key aspects of viticulture, is indeed strongly tied to the heat accumulation conditions at each site”

Reply: Done.

Lines 45 Add the following sentence “In effect, air temperature is considered the main forcing factor of grapevine phenology [8,9], harvest timings, solid soluble, and aroma concentration [10-11]”.

[10] Cataldo, E., Fucile, M., & Mattii, G. B. (2022). Effects of Kaolin and Shading Net on the Ecophysiology and Berry Composition of Sauvignon Blanc Grapevines. Agriculture, 12(4), 491.

[11] Leng, F., Wang, C., Sun, L., Li, P., Cao, J., Wang, Y., ... & Sun, C. (2022). Effects of Different Treatments on Physicochemical Characteristics of ‘Kyoho’Grapes during Storage at Low Temperature. Horticulturae, 8(2), 94.

Reply: Done.

Line 56 “The sigmoid model” briefly explain

Reply: The following explanation was added:

“The sigmoid model follows a curve that can be used to characterize berry development and sugar accumulation, starting with a rapid increase phase until it reaches a plateau phase, when sugar content stabilizes [22].”

Authors should replace DOYs with standard days for easier reading (graphics and text).

Reply: We choose to use the DOY (Day of Year) because it is a widely used term in the viticultural/phenological sciences field. We would like to keep this term.

Reviewer 4 Report

- Do you think that it is possible to use a 'e' value fixed for all sites?

Maybe the model could be modify in order to have a 'e' value fixed.

- Do you think that the model could be apply to locations out of Douro region?

- Figure 8: Where is the line representing the 2021 sugar concentration?

Author Response

Reviewer #4

Reply: We would like to thank the Reviewer for his/her comments, which have contributed to improve our study. The point-by-point replies are provided below and highlighted in blue font, as well as the corresponding changes in the manuscript

- Do you think that it is possible to use a 'e' value fixed for all sites? Maybe the model could be modify in order to have a 'e' value fixed.

Reply: Although it would be useful to provide a “fit for all” model, in our finding a universal e- provided poor results. Therefore we found that the e- should always be calibrated. Nonetheless, we have included a tool to do this calibration automatically.

- Do you think that the model could be apply to locations out of Douro region?

Reply: We believe this would be possible, not just for the Douro but also for many other winemaking regions. Although it would require more data for calibration.

- Figure 8: Where is the line representing the 2021 sugar concentration?

Reply: The 2021 line is behind the simulation line as they are concurrent.

Round 2

Reviewer 2 Report

All suggested edits were revised and/or explained, no further edits required