The Effect of N and KH2PO4 on Skin Color, Sugars, and Organic Acids of “Flame Seedless” Grape
Round 1
Reviewer 1 Report
Dear Authors,
The subject of the study is interesting and topical, with scientific and practical importance.
The introduction is presented correctly, in accordance with the subject. Numerous scientific articles, in concordance to the topic of the study, were consulted.
Methodology of the study was clearly presented, and appropriate to the proposed objectives.
The obtained results are important and have been analyzed and interpreted correctly, in accordance with the current methodology.
The discussions are appropriate, in the context of the results, and was conducted compared to other studies in the field.
The scientific literature, to which the reporting was made, is recent and representative in the field.
Some suggestions and corrections were made in the article.
The following aspects are brought to the attention of the authors.
1.
According to Instructions for Authors, and Microsoft Word template, Agronomy journal, it is recommended to refer to a figure or a table in the text, before presenting them.
On the other hand, it is not the most suitable for a subchapter to start directly with a figure.
eg Page 8, Figure 3.
It is recommended to revise, and the paragraph that refers to figure 3 to be positioned before the figure, at the beginning of the subchapter.
Similar recommendations, regarding Table 3, page 9, and Table 4, page 11.
2
References
According to Instructions for Authors, and Microsoft Word template, Agronomy journal,
“Author 1, A.B.; Author 2, C.D. Title of the article. Abbreviated Journal Name Year, Volume, page range.”
eg
page 17, row 517
“259” instead of “259”
Page 17, row 530
“62(1),” instead of “62, (1),”
It is recommended to review the entire References chapter, and correct it, if necessary.
Comments for author File: 
Comments.pdf
Author Response
1. According to Instructions for Authors, and Microsoft Word template, Agronomy journal, it is recommended to refer to a figure or a table in the text, before presenting them. On the other hand, it is not the most suitable for a subchapter to start directly with a figure.
e.g Page 8, Figure 3.
It is recommended to revise, and the paragraph that refers to figure 3 to be positioned before the figure, at the beginning of the subchapter.
Similar recommendations, regarding Table 3, page 9, and Table 4, page 11.
Answer: Thank you for your suggestion. Figure 3, Table 3 and Table 4 have been placed after their explanatory paragraphs. (Figure 3, Page 9; Table 3, Page 10; Table 4, Page 11)
2. References
According to Instructions for Authors, and Microsoft Word template, Agronomy journal,
“Author 1, A.B.; Author 2, C.D. Title of the article. Abbreviated Journal Name Year, Volume, page range.”
eg
page 17, row 517
“259” instead of “259”
Page 17, row 530
“62(1),” instead of “62, (1),”
It is recommended to review the entire References chapter, and correct it, if necessary.
Answer: Thank you for your suggestion. We have reviewed the entire References chapter, and corrected it. We have modified “259” to “259”, “62, (1)” to “62(1)”, “111, (4)” to “111(4)”, “17, (4)” to “17(4)”, “39, (1)” to “39(1)”, “57, (10)” to “57(10)”, and “158, (1)” to “158(10)”. (References, Lines 528, 540, 578, 587, 591, 605, 636)
Author Response File: Author Response.pdf
Reviewer 2 Report
The work needs some modifications to be accepted.
Particularly:
- the word 'Flavor' is indicated in the title, but the flavor is neither defined nor discussed in the manuscript
- the amount of Nitrogen tested is decidedly excessive - the production per plant or per hectare is not reported
- in evaluating the quality of table grapes the sugar/acid ratio is used, why is it not used?
- a more complex and comprehensive statistic (ANOVA type) would be appropriate, able to separate the factors of variation keeping in mind the nitrogen levels, the years...
Some observations are reported in the attached file.
Comments for author File: Comments.pdf
Author Response
1.the word 'Flavor' is indicated in the title, but the flavor is neither defined nor discussed in the manuscript
Answer: Thank you for your suggestion. We have modified the title of the article to “The Effect of N and KH2PO4 on Skin Color, Sugars and Organic acids of ‘Flame seedless’ grape”. (Title, lines 2,3)
2.the amount of Nitrogen tested is decidedly excessive - the production per plant or per hectare is not reported
Answer: The three nitrogen treatments in this paper are set up according to the conclusions of the previous experiments. The reason for the relatively high nitrogen application rate could be that (1) the vines are relatively large, (2) the entire fertilization process only uses chemical fertilizer as base fertilizer, and (3) the soil is relatively poor.
We did not calculate yield per vine or yield per hectare because we pruned the vines uniformly, leaving 6 ears of fruits per vine.
3. in evaluating the quality of table grapes the sugar/acid ratio is used, why is it not used?
Answer: Thank you for the suggestion. The sugar/acid ratio is very important for quality of table grapes. In this paper, we assessed the internal quality of table grapes using soluble solids, pH of grape juice, firmness of grape berry, soluble sugar and organic acid content. We will revise if you believe these data are insufficient to assess the quality of table grapes.
4. a more complex and comprehensive statistic (ANOVA type) would be appropriate, able to separate the factors of variation keeping in mind the nitrogen levels, the years...
Answer: Thank you for your insightful suggestion. In future studies, multiple variables such as nitrogen, KH2PO4 and year will be analyzed separately and cross-over.
Author Response File: Author Response.pdf
Reviewer 3 Report
Dear authors,
It was my pleasure to go over this manuscript. Please check the attached file.
Comments for author File: Comments.pdf
Author Response
1. Could you please add some numbers about China's grapes industry, and compare it to the global industry?
Answer: Thank you for your suggestion. We have added “Grape (Vitis vinifera L.) is one of the four most widely cultivated fruits in the world. Since 2011, China has become the largest producer of table grapes [1] in introduction”. (Induction, lines 31-32)
Reference
1. Xia H, Shen Y, Deng H, Wang J, Lin L, Deng Q, Lv X, Liang D, Hu R, Wang Z, Xiong B: Melatonin application improves berry coloration, sucrose synthesis, and nutrient absorption in 'Summer Black' grape. Food Chemistry 2021, 356:129713.
2. Could you mention environmental factors that affect grape coloration under the China conditions, relevant specifically to your targeted cultivar 'Flame' and the coloration problem
Answer: Thank you for your suggestion. We have added “In warm climate regions, red table grapes often present color deficits that decrease their commercial value. Grape color can be affected by many different factors, among them, temperature, light intensity, nutrition, and irrigation [2]” in introduction. (Induction, lines 37-40)
Reference
2. Pinillos V, Ibanez S, Cunha JM, Hueso JJ, Cuevas J: Postveraison Deficit Irrigation Effects on Fruit Quality and Yield of "Flame Seedless" Table Grape Cultivated under Greenhouse and Net. Plants (Basel) 2020, 9:9111437.
3.How did you identify the commercial maturity?
Answer: The commercial maturity of grape was determined according to the minimum edible standard (15% ≤ total soluble sugar content ≤ 18.00%). Table grapes with soluble solids between 15% and 18% are suitable for picking [1]. (Materials and Methods, line 116)
Reference
1. Mikulic-Petkovsek M, Skvarc A, Rusjan D: Biochemical composition of different table grape cultivars produced in Slovenia. The Journal of Horticultural Science and Biotechnology 2018, 94:368-377.
3. The 5 acetylation, 7 coumarylation and 5 basic anthocyanins. Where in the table?
Answer: They are in the two leftmost columns of table 3.
Generally, grape anthocyanins are derived from five main 3-O-glucoside forms, including cyanidin-3-O-glucoside (Cy), peonidin-3-O-glucoside (Pn), delphindin-3-O-glucoside (Dp), petunidin-3-O-glucoside (Pt), and malvidin-3-O-glucoside (Mv), as well as lower amounts of pelargonidin-3-O-glucoside (Pg); further esterification to an acetyl (acet), coumaryl (coum) or caffeoyl (caff) group can occur at the glucose 6-position.
4. What did you mean by 'not detected?. You already have values!
Answer: Yes, the contents of malvidin-3-O-(c-6-O-p-coumaryl)-glucoside and peonidin-3-O-(6-O-acetyl)-glucoside were 0 (Table 3).
5. The value is there '1.59'. It is already detected, but might be to small level. So, you have to rephrase this sentence. 'Not detected' does not make sense in this regard.
Answer: The 1.59 was Delphinidin-3-O-glu-coside content, not Delphinidin-3-O-(6-O-p-coumaryl)-glucoside content.
6. Where are the * on the graph? How did you compare statistically?
Answer: ∗ represent that the N and KH2PO4 treatment were significantly different from their corresponding N treatments using a one-tailed Student’s t-test (p < 0.05). For example, HNK is compared to HN, MNK is compared to MN and LNK is compared to LN in the same period and year.
7. Please re-check the DMRT letters for MN and HN at 56 days in 2020. Should be the opposite. In other words, MN should be 'a' and HN should be 'b', even thought they both do not significantly different based on the SD bars. It seems that they both take 'a'
Answer: The letters at the top of the bar chart represent ANOVA values for glucose among treatments (Figure 4).
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
According to my previous revision the Authors did not consider the following points:
2.the amount of Nitrogen tested is decidedly excessive - the production per plant or per hectare is not reported
Answer: The three nitrogen treatments in this paper are set up according to the conclusions of the previous experiments. The reason for the relatively high nitrogen application rate could be that (1) the vines are relatively large, (2) the entire fertilization process only uses chemical fertilizer as base fertilizer, and (3) the soil is relatively poor.
- Any explanations have been reported in the revised manuscript
3. in evaluating the quality of table grapes the sugar/acid ratio is used, why is it not used?
Answer: Thank you for the suggestion. The sugar/acid ratio is very important for quality of table grapes. In this paper, we assessed the internal quality of table grapes using soluble solids, pH of grape juice, firmness of grape berry, soluble sugar and organic acid content. We will revise if you believe these data are insufficient to assess the quality of table grapes.
- No revision has been done.
4. a more complex and comprehensive statistic (ANOVA type) would be appropriate, able to separate the factors of variation keeping in mind the nitrogen levels, the years...
Answer: Thank you for your insightful suggestion. In future studies, multiple variables such as nitrogen, KH2PO4 and year will be analyzed separately and cross-over.
- No ANOVA statistic has been done
Comments for author File: Comments.pdf
Author Response
1.the amount of Nitrogen tested is decidedly excessive
Answer: Using 14 a ‘Kyoho’ grapes as the test material, the study of Sun et al. [1] showed that the quality of grapes treated with an application amount of 41 g/vine was the best. Using 8a ‘Pinot Noir’ as the test material. The vines treated with 300 and 450 kg/hm2 nitrogen significantly improve berry quality [2]. Different tree ages and experimental sites lead to different amounts of fertilization. The three nitrogen treatments in this paper are set up according to the fertilization experience of local fruit farmers and conclusions of the previous experiments [3]. The amount of chemical fertilizer applied per vine was 184.00 g N, 87.32 g P, and 398.30 g K. The research material consisted of 5-year-old ‘Kyoho’ grape plants.
Reference
1. Sun, C, Yang. L, Chen, Z, Niu, S, Zhao,Y, Wei ,J, Chu,F: Effects of nitrogen application on growth and fruit quality of 'Kyoho' Grape. Hebei Agricultural Sciences 2017, 21:38-41.
2. He, Y, Lu, H, Guo, Y, Jia, J, Li, W, Mao, J, Ma,Z, Chen, B: Effects of nitrogen application on leave physiology characteristics and in-fruit accumulation of sugar and anthocyanin of wine grape.Journal of Gansu Agricultural University 2021, 56: 56-63+72.
3. Wu L, Li P, Jia H, Phillip FO, Bao X, Zhao F, Zhao B, Feng J, Yu K: The Effect of Foliar Application of K2SO4 or KH2PO4 on Skin Color of the ‘Kyoho’ Grape. Agronomy 2021, 11:2361.
2. a more complex and comprehensive statistic (ANOVA type) would be appropriate, able to separate the factors of variation keeping in mind the nitrogen levels, the years...
Answer: In this study, different lowercase letters after data within the same period and year indicate a significant difference between the three N treatments;
Different uppercase letters after data within the same period and year indicate a significant difference between the combined N and KH2PO4 treatments using Duncan’s multiple range test (DMRT) at p < 0.05.
∗ represent that the N and KH2PO4 treatment were significantly different from their corresponding N treatments using a one-tailed Student’s t-test (p < 0.05). For example, HNK is compared to HN, MNK is compared to MN and LNK is compared to LN in the same period and year.
The year was not a variable, but a two-year replicate of the experiment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Dear authors,
Please find attached my comments on the revised version, including your response to "some" of my previous comments. Please go over the entire manuscript again, and respond to all of my previous comments, and make the manuscript in a better shape for publication.
Comments for author File: Comments.pdf
Author Response
1. No response on this point:
'Could you add 3-4 sentences on the physiological role of N & K on berry color?'
Answer: We are sorry, we did not find the relevant literature.
2. No Answer:
"What was the reason of early eye opening and late blooming in the second season?. Was it a weather issue?"
Answer: In the spring of 2021, there was a late spring coldness, which delayed the flowering of the grapes.
3. Why did not you test firmness for intact berries?
Answer: The size of ‘Flame seedless” berries was small and the grape skin is hard. Using the whole grape to determine the firmness is easily damaged and the data are unstable. Therefore, the whole grape was not used for the determination of grape hardness.
4. I know that the letters on top of the bars are for comparison of the ANOVA means using DMRT, but sine you already put them in descending order, how MN at 56 days in 2020 is higher than HN at the same 56 days in 2020, meanwhile it is represented by 'b' rather than 'a'. It should be vise versa.
Answer: Table 1 shows the data for glucose content in Figure 4 of the article.
Table 1. Effects of foliar spraying of KH2PO4 on the glucose content (mg·g-1) in berries under three soil-applied N levels in 2020 and 2021.
|
Glucose |
|
56d |
70d |
84d |
|
|
LN |
114.20±4.20b |
125.88±2.74b |
142.60±2.07b |
|
|
LNK |
115.78±3.09C |
150.20±0.17A |
150.85±4.81B |
|
2020 |
MN |
118.70±2.63b |
138.80±1.96a |
151.28±6.33a |
|
|
MNK |
129.10±2.33A |
151.23±0.63A |
155.88±0.97A |
|
|
HN |
124.67±2.05a |
129.10±1.08b |
145.50±2.14ab |
|
|
HNK |
121.53±2.03B |
142.53±1.29B |
147.40±2.22B |
|
|
|
|
|
|
|
|
LN |
96.54±0.33a |
107.32±0.14ab |
120.71±0.55a |
|
|
LNK |
98.31±1.85B |
114.27±0.16A |
121.82±0.48B |
|
2021 |
MN |
98.00±0.40a |
110.36±3.97a |
121.07±1.34a |
|
|
MNK |
100.62±2.54A |
114.30±1.48A |
124.49±1.66A |
|
|
HN |
97.35±1.56a |
104.59±1.08b |
119.51±1.84a |
|
|
HNK |
97.54±0.89B |
112.64±0.62B |
121.36±0.69B |
Author Response File: Author Response.pdf
