Pre-Harvest Seaweed Biostimulant Applications: Optimizing Concentration, Timing, and Frequency for Cultivar-Specific Improvements in Potato Yield and Quality

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors did a great effort in conducting this study. However, several aspects of the experimental design, data presentation, and statistical analysis limit the strength of the conclusions drawn.

1. Selection of the biostimulant: The manuscript does not adequately justify the choice of the tested biostimulant. In addition, the composition of the biostimulant was not characterized. Analyzing different biostimulants would have strengthened the study and provided a more comprehensive comparison of their effectiveness.
2. Selection of cultivars: The rationale for choosing the evaluated cultivars is not sufficiently explained. Cultivar performance is strongly influenced by environmental conditions, and the observed responses may differ under other climatic or agronomic settings. Evaluating a larger number of cultivars and testing them under diverse environmental conditions would improve the robustness and applicability of the findings, helping to identify treatments that remain effective across different cultivars and growing environments.
3. Statistical analysis and data presentation: The presentation of the data makes it difficult to clearly distinguish differences among treatments. The use of the LSD test does not facilitate straightforward interpretation of treatment effects. The authors should consider applying more commonly used multiple comparison procedures, such as Duncan's Multiple Range Test or Tukey's Honest Significant Difference (HSD) test, to provide clearer comparisons among treatments. In addition, multivariate statistical approaches such as principal component analysis (PCA), heatmaps, or cluster analysis could be included to facilitate data interpretation and provide a more comprehensive understanding of treatment effects.
4. Presentation of results: The manuscript contains a large amount of data, some of which may not be essential to the main conclusions. The authors should focus on presenting the most relevant and informative results, thereby improving readability and clarity.
5. Use of pesticides and herbicides: The experiment involved the application of pesticides and herbicides. The use of these chemical products must be avoided.
6. Redundancy of information: Several pieces of information are repeated throughout the manuscript. Reducing redundancy would improve the overall flow and readability of the paper.
7. Figure correction: There appears to be an error in Figure 1. In Experiment 1, Treatment 5, the BIO concentration is reported as 2 g L⁻¹, whereas it should be 7.2 g L⁻¹. The authors should verify and correct this value.
8. Table titles: All tables should include clear and informative titles to improve readability and facilitate interpretation of the results.
9. Interpretation of results: Some statements do not appear to be fully supported by the presented data. For example, the sentence: “For the postharvest experiments in Table 2, compared to the harvest, 3 months of storage at 7.5 °C resulted in a reduction in SC while increasing RSC, irrespective of cultivar or treatment.” does not seem consistent with Table 2, where no significant differences among treatments are evident.

 

 

Author Response

Thank you for your review of our manuscript, “Pre-Harvest Seaweed Biostimulant Applications: Optimizing Concentration, Timing, and Frequency for Cultivar-Specific Improvements in Potato Yield and Quality” (ID: horticulturae-4370967). We have thoroughly read the comments from the review team and revised the manuscript accordingly. Please find our point-by-point explanation in red to each of the comments raised by the team below.

1.Selection of the biostimulant: The manuscript does not adequately justify the choice of the tested biostimulant. In addition, the composition of the biostimulant was not characterized. Analyzing different biostimulants would have strengthened the study and provided a more comprehensive comparison of their effectiveness.

Response: Stimplex^® extracted from Ascophyllum nodosum was supplied by Acadian Seaplants Limited Company. The composition of the BIO was analyzed by the company and submitted to the US EPA. According to the label (please, see the website), the BIO contained 0.01% cytokinin and 99.99% other ingredients. It is a plant growth regulator extracted from specially selected marine plants that improves resistance to biotic and abiotic stresses, enhances overall plant health, increases nutrient levels, increases root growth and early plant development, increases fruit set and size, and increases yield; improve crop quality. Our study confirmed that Stimplex^® improved the yield and quality attributes.

 

https://www3.epa.gov/pesticides/chem_search/ppls/075287-00003-20240610.pdf

2.Selection of cultivars: The rationale for choosing the evaluated cultivars is not sufficiently explained. Cultivar performance is strongly influenced by environmental conditions, and the observed responses may differ under other climatic or agronomic settings. Evaluating a larger number of cultivars and testing them under diverse environmental conditions would improve the robustness and applicability of the findings, helping to identify treatments that remain effective across different cultivars and growing environments.

Response: We agreed with the comment that cultivar performance was strongly influenced by environmental conditions. In Qinghai province, ‘Minshu No. 1’, ‘Leshu No. 1’, ‘Xiazhai 65’, ‘Qingshu No. 2’, ‘Qingshu No. 10’, and ‘Qingshu No. 9’ are the main potato cultivars. We did not know whether the BIO could be still working on these cultivars in other provinces. However, our work provided more information for growers and researchers to test in the other location or country.

3.Statistical analysis and data presentation: The presentation of the data makes it difficult to clearly distinguish differences among treatments. The use of the LSD test does not facilitate straightforward interpretation of treatment effects. The authors should consider applying more commonly used multiple comparison procedures, such as Duncan's Multiple Range Test or Tukey's Honest Significant Difference (HSD) test, to provide clearer comparisons among treatments. In addition, multivariate statistical approaches such as principal component analysis (PCA), heatmaps, or cluster analysis could be included to facilitate data interpretation and provide a more comprehensive understanding of treatment effects.

Response: We used the Tukey’s honestly significant difference (HSD) to replace the Fisher’s protected LSD test in this study. In addition, PCA was added in this study.

4.Presentation of results: The manuscript contains a large amount of data, some of which may not be essential to the main conclusions. The authors should focus on presenting the most relevant and informative results, thereby improving readability and clarity.

Response: We revised the Results.

5.Use of pesticides and herbicides: The experiment involved the application of pesticides and herbicides. The use of these chemical products must be avoided.

Response: Our study did not involve the application of pesticides and herbicides. The pesticides and herbicides that mentioned in 2.1. Plant Material was just used in field management.

6.Redundancy of information: Several pieces of information are repeated throughout the manuscript. Reducing redundancy would improve the overall flow and readability of the paper.

Response: Revised.

7.Figure correction: There appears to be an error in Figure 1. In Experiment 1, Treatment 5, the BIO concentration is reported as 2 g L⁻¹, whereas it should be 7.2 g L⁻¹. The authors should verify and correct this value.

Response: Revised. The figure was changed to Table 1.

8.Table titles: All tables should include clear and informative titles to improve readability and facilitate interpretation of the results.

Response: All table information were added.

9.Interpretation of results: Some statements do not appear to be fully supported by the presented data. For example, the sentence: “For the postharvest experiments in Table 2, compared to the harvest, 3 months of storage at 7.5 °C resulted in a reduction in SC while increasing RSC, irrespective of cultivar or treatment.” does not seem consistent with Table 2, where no significant differences among treatments are evident.

Response: Deleted.

Reviewer’s comments on this manuscript have been considered and corrected accordingly.

Thank you for the opportunity to improve the MS. I will look forward to your reply. Please do not hesitate to contact me should you request additional information.

Sincerely

Yu Dong,

Qinghai University

Qinghai Academy of Agriculture and Forestry Sciences

No. 253 Ningda Road

Xining, Qinghai 810016, China

Email address: yu.dong@qhu.edu.cn; dongyu8306@hotmail.com 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript submitted to Horticulturae meets the thematic scope of the journal. It addresses important issues related to improving potato yield and enhancing its nutritional value through the application of biopreparations. The manuscript is well written and has an appropriate structure. The introduction focuses on the importance of potato as a crop, as well as the need to ensure its quality and storage longevity. The topic of biopreparations and their benefits is also discussed, while research gaps in this area are clearly indicated. The aim of the study has been formulated appropriately.

The research methodology is described in great detail. The experimental design contains a large amount of detail, which makes it difficult to understand; however, the scheme clarifies everything. Nevertheless, the quality of Figure 1 should be improved.

The statistical analysis is very limited. In my opinion, a more conservative post hoc test (e.g., Tukey’s test) should be applied, provided that the data meet the assumptions of normality and homogeneity of variance. It is also worth considering whether a correlation analysis (Pearson or Spearman) should be performed.

Attention should be paid to the journal’s editorial requirements, as the formatting of the manuscript is chaotic.

In the Results and Discussion chapter, section 3.1 lacks a discussion of the findings in relation to the literature. The discussion appears only in section 3.2. In my opinion, the Results and Discussion chapter should be divided into two separate chapters, which would likely make it easier for the authors to confront their findings with the existing literature.

In the paragraph entitled “The Efficacy of BIO on Nutrient Uptake in Potatoes,” the authors indicate a beneficial effect of BIO on the increased uptake of certain elements (K, Zn, and Cu). However, it is well known that excessively high concentrations of these elements in food may not be favorable from a health perspective. This issue should therefore be discussed.

In the Conclusion section, the authors should also indicate directions for future research and acknowledge potential limitations of the study. In particular, I would raise for discussion the increased uptake of potassium, as well as iron and zinc, and the possible consequences of this for human health.

Overall, I believe that the manuscript addresses a relevant topic and has scientific merit; however, it requires revision before it can be considered for publication. Therefore, I recommend major revision.

Author Response

Thank you for your review of our manuscript, “Pre-Harvest Seaweed Biostimulant Applications: Optimizing Concentration, Timing, and Frequency for Cultivar-Specific Improvements in Potato Yield and Quality” (ID: horticulturae-4370967). We have thoroughly read the comments from the review team and revised the manuscript accordingly. Please find our point-by-point explanation in red to each of the comments raised by the team below.

Reviewer: 2

The manuscript submitted to Horticulturae meets the thematic scope of the journal. It addresses important issues related to improving potato yield and enhancing its nutritional value through the application of biopreparations. The manuscript is well written and has an appropriate structure. The introduction focuses on the importance of potato as a crop, as well as the need to ensure its quality and storage longevity. The topic of biopreparations and their benefits is also discussed, while research gaps in this area are clearly indicated. The aim of the study has been formulated appropriately.

The research methodology is described in great detail. The experimental design contains a large amount of detail, which makes it difficult to understand; however, the scheme clarifies everything. Nevertheless, the quality of Figure 1 should be improved.

Response: We agreed with this comment. Thus, we deleted the Fig. 1 and replace it by Table 1.

The statistical analysis is very limited. In my opinion, a more conservative post hoc test (e.g., Tukey’s test) should be applied, provided that the data meet the assumptions of normality and homogeneity of variance. It is also worth considering whether a correlation analysis (Pearson or Spearman) should be performed.

Response: We used the Tukey’s honestly significant difference (HSD) to replace the Fisher’s protected LSD test in this study. The PCA was employed in this study.

Attention should be paid to the journal’s editorial requirements, as the formatting of the manuscript is chaotic.

Response: Revised.

In the Results and Discussion chapter, section 3.1 lacks a discussion of the findings in relation to the literature. The discussion appears only in section 3.2. In my opinion, the Results and Discussion chapter should be divided into two separate chapters, which would likely make it easier for the authors to confront their findings with the existing literature.

Response: “3. Results and Discussion” was changed to “3. Results” and “4. Discussion”.

In the paragraph entitled “The Efficacy of BIO on Nutrient Uptake in Potatoes,” the authors indicate a beneficial effect of BIO on the increased uptake of certain elements (K, Zn, and Cu). However, it is well known that excessively high concentrations of these elements in food may not be favorable from a health perspective. This issue should therefore be discussed.

Response: We agreed with this comments. Now, this paragraph was read as “Nutrient uptake is a critical determinant of potato growth, tuber yield, and quality ^[31-32], and the present study demonstrated that BIO application exerted distinct effects on the accumulation of key macro- and micro-nutrient in potato tubers. However, the capacity of macro- and micronutrient uptake in BIO was affected by the cultivar-specific responses (Table 8). For example, 7.2 g/L BIO sprays 3 times significantly increased K and Fe contents in ‘Minshu No. 1’ potatoes by 8.95% and 13.53%, respectively, compared to the control. The 3 applications of 7.2 g/L BIO increased the K and Zn contents in ‘Xiazhai 65’ potatoes by 6.86% and 31.50%, respectively, compared to the control. In contrast, ‘Qingshu No. 9’ potatoes showed no significant changes in nutrient uptake across all BIO treatments. While increased uptake of micronutrients like Fe and Zn is generally associated with improved nutritional quality, it is important to consider potential health implications. K is an essential electrolyte, and while higher levels are generally beneficial for cardiovascular health, excessive intake can be problematic for individuals with renal impairment. Similarly, while Fe and Zn are crucial for preventing deficiencies, excessively high concentrations in food crops can theoretically lead to adverse health effects if dietary intake exceeds recommended tolerable upper intake levels, although the levels observed in this study are unlikely to pose immediate health risks. Therefore, while BIO-induced biofortification was beneficial for the general population, its impact on specific sensitive groups should be considered in future nutritional assessments. Regarding the study’s scope, although this research focused on K, Ca, Mg, Fe, and Zn due to their direct impact on tuber quality and stress resilience, we acknowledge that N and phosphorus (P) are also primary macronutrients essential for potato growth. Previous research has indicated that Ascophyllum nodosum extracts enhance nutrient acquisition through stimulating root system development ^[33], activating soil enzymes that facilitate nutrient mineralization ^[34], and up-regulating the expression of nutrient transporter genes in roots ^[35-36]. Although we did not measure N and P uptake in this trial, the observed increases in K and Zn suggested that BIO likely improved overall root foraging efficiency, which would presumably benefit the uptake of other mobile nutrients like N and P as well. Future studies should include comprehensive analysis of N and P to fully elucidate the nutrient mobilization mechanisms of BIO in potatoes.”.

In the Conclusion section, the authors should also indicate directions for future research and acknowledge potential limitations of the study. In particular, I would raise for discussion the increased uptake of potassium, as well as iron and zinc, and the possible consequences of this for human health.

Response: Revised. Now, this section was read as “his study demonstrated that the efficacy of BIO application was highly dependent on cultivar, spraying concentration, frequency, and timing. These findings proposed the following practical recommendations for potato growers: For early- and mid-maturing cultivars (i.e., ‘Minshu No. 1’, ‘Leshu No. 1’, and ‘Xiazhai 65’), pre-harvest application of 7.2 g/L BIO applied 3 to 4 times during critical developmental stages from seedling to 3 weeks after FB was recommended. This protocol significantly increased tuber yield, particularly of medium/large-sized tubers, and enhanced the accumulation of K, Fe, and Zn. Furthermore, this treatment maintained DMC and SC after storage and reduced post-harvest losses. For late-maturing cultivars (i.e., ‘Qingshu No. 9’ and ‘Qingshu No. 10’), no significant yield or quality response was observed to the tested BIO parameters. Therefore, a BIO application was not currently recommended for these late-maturing varieties. Growers should select responsive cultivars or alternative strategies if targeting late-maturing varieties. Although the experimental fields were conventionally fertilized, the primary goal was not to correct nutrient deficiencies but to optimize yield potential and tuber quality in a high-potential environment. In such well-managed systems, BIO served to enhance physiological efficiency, improve stress resilience, and elevate the nutritional quality of tubers beyond standard fertilization limits. This approach added value by extending shelf-life stability and enhancing nutrient density. Therefore, the BIO application should be viewed as a strategy for quality enhancement and yield improvement in responsive cultivars, rather than a substitute for standard agronomic practices. Despite these promising results, this study has certain limitations. The experiments were conducted under conventional fertilization conditions in Qinghai Plateau, which may limit the generalizability of the findings to other soil types or climatic zones. Additionally, the specific formulation of the BIO used (Stimplex^®) may yield different results with other seaweed extracts. Future research should address these limitations by investigating the uptake of N and P alongside micronutrients, exploring the molecular mechanisms underlying cultivar-specific responses, conducting multi-year, multi-location field trials to validate the stability of these findings under diverse environmental conditions, and assessing the long-term nutritional impact of increased micronutrient uptake on human health.”.

Reviewer’s comments on this manuscript have been considered and corrected accordingly.

Thank you for the opportunity to improve the MS. I will look forward to your reply. Please do not hesitate to contact me should you request additional information.

Sincerely

Yu Dong,

Qinghai University

Qinghai Academy of Agriculture and Forestry Sciences

No. 253 Ningda Road

Xining, Qinghai 810016, China

Email address: yu.dong@qhu.edu.cn; dongyu8306@hotmail.com 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

General Comments The manuscript investigates the application of algal biostimulants on potatoes, focusing on optimizing application parameters to improve yield and quality. The study is interesting and merits publication. It is well-structured and provides a wealth of data illustrating the high variability in biostimulant efficacy and its dependence on multiple factors. However, I strongly recommend a thorough review to improve readability before publication. Additionally, please insert continuous line numbers in the manuscript to facilitate the peer review process.

Abstract Please clarify what is meant by "four frequencies"; does this refer to the number of applications? The abstract currently contains an overwhelming amount of information, which makes it dispersive and confusing, especially considering the large number of treatments and quality parameters. I suggest condensing this section to focus on the main findings, providing a broader overview of the work performed.

Introduction When stating "In potatoes, pre-harvest foliar application of 10 g L-1 BIO extracted from seawater brown alga increased...", please specify which brown algae was used. Furthermore, you state that "no commercial practice of using BIO on potatoes has been well reported." Weren't the previously cited examples conducted on commercial varieties? Please clarify what you mean by "commercial." I also recommend expanding the introduction to better explain what biostimulants are, their mechanisms of action, and their application methods, including dosages and timings. Given that your work is entirely based on modifying these parameters, a more detailed background is essential.

Materials and Methods Potatoes were harvested between 85 and 135 days after planting. While this is inherently linked to the use of early, mid, and late-maturing cultivars, I suggest stating this relationship explicitly to avoid confusion. Regarding the biostimulant concentrations, please explain the rationale behind their selection. Do you suspect a direct fertilizing effect at such high concentrations? Other studies have reported excellent results using much lower biostimulant concentrations, such as 0.5 g/L. Please renumber the three experimental subsections as 2.2.1, 2.2.2, and 2.2.3. The experimental design is unclear, particularly the rationale for selecting different cultivars for each experiment. Please provide a stronger justification, as it is currently unclear why the same cultivars were not maintained across all trials. The sentence explaining that the early-maturing cultivar was selected for the subsequent experiment due to its high response to 7.2 g/L BIO should be moved directly into the Experiment 2 description. Additionally, the text block immediately preceding section 2.3 appears to be the caption or internal text of Figure 1; please format this properly to avoid it looking like a repetitive paragraph in the main text. I also suggest creating a comprehensive table to summarize all applied treatments, as the current text description is highly dispersive. In section 2.3, please format the weight-based categories clearly. Finally, in section 2.5, was there a minimum sprout length considered for the evaluation?

Results Please check the formatting of all table captions, as they are currently disjointed. Furthermore, the statistical analysis approach is unclear. Why were statistics performed across all cultivars combined rather than individually within each cultivar? This raises questions about the primary rationale of the experiment: was it to evaluate whether biostimulants work, or to assess differences between cultivars? I strongly suggest performing the statistical analysis only within the same cultivar. This would yield more representative and meaningful information. By combining all cultivars, you risk masking important data and diminishing the significance of treatment effects relative to their specific controls.

Discussion In Section 4.1, you provide examples of biostimulant use on other species, such as sweet cherries and cucumbers. This requires a better introduction, as it is initially unclear why these examples are relevant to a study on potatoes. Furthermore, please clarify whether these cited studies used the exact same biostimulant or completely different formulations. It must also be noted that, by definition, biostimulants target abiotic stress, not biotic stress. Therefore, effects against fungal diseases cannot technically be classified as biostimulant activity. Regarding nutrient uptake, while you evaluated important macro- and micronutrients like K, Ca, Mg, Fe, and Zn, it is a pity that you did not investigate the uptake of other primary macronutrients, specifically Nitrogen and Phosphorus.

Conclusions Given that you tested early, mid, and late-maturing cultivars, could you provide practical recommendations for biostimulant use based on these specific maturity profiles? Instead of merely summarizing the results, please provide a clear take-home message, moving beyond the already established fact that biostimulant efficacy varies according to multiple parameters. Finally, considering that the experimental fields were conventionally fertilized, what was the specific objective of biostimulation in this context? Generally, biostimulants are applied to counteract abiotic stress, improve yield in marginal or nutrient-poor soils, or reduce the overall application of standard fertilizers.

Author Response

Thank you for your review of our manuscript, “Pre-Harvest Seaweed Biostimulant Applications: Optimizing Concentration, Timing, and Frequency for Cultivar-Specific Improvements in Potato Yield and Quality” (ID: horticulturae-4370967). We have thoroughly read the comments from the review team and revised the manuscript accordingly. Please find our point-by-point explanation in red to each of the comments raised by the team below.

 

Reviewer: 3

General Comments The manuscript investigates the application of algal biostimulants on potatoes, focusing on optimizing application parameters to improve yield and quality. The study is interesting and merits publication. It is well-structured and provides a wealth of data illustrating the high variability in biostimulant efficacy and its dependence on multiple factors. However, I strongly recommend a thorough review to improve readability before publication. Additionally, please insert continuous line numbers in the manuscript to facilitate the peer review process.

Response: Revised. The line numbers was added in this study.

 

Abstract Please clarify what is meant by "four frequencies"; does this refer to the number of applications? The abstract currently contains an overwhelming amount of information, which makes it dispersive and confusing, especially considering the large number of treatments and quality parameters. I suggest condensing this section to focus on the main findings, providing a broader overview of the work performed.

Response: Revised. Now the abstract was read as “The aim of this study was to optimize the pre-harvest application of seaweed-based biostimulants (BIO) to improve potato yield, quality, and post-storage attributes. To achieve this, six potato cultivars differing in maturity periods were subjected to three BIO concentrations (2.4, 7.2, and 9.6 g/L), application timings (from planting to post-bloom), and frequencies (1-4 applications). Results indicated that BIO efficacy was strongly cultivar-specific. Responsive cultivars (such as ‘Minshu No. 1’, ‘Leshu No. 1’, ‘Xiazhai 65’, and ‘Qingshu No. 2’) showed significant yield increases when treated with 7.2 or 9.6 g/L BIO applied 3 to 4 times during key developmental stages (from seedling to 3 weeks after full bloom). In contrast, ‘Qingshu No. 10’ and ‘Qingshu No. 9’ exhibited no significant response. Post-storage analysis revealed that optimal BIO treatments in responsive cultivars (‘Minshu No. 1’ and ‘Xiazhai 65’) delayed the losses in dry matter content and starch content after 3 months of storage at 7.5 °C. Furthermore, BIO application significantly enhanced the uptake of potassium (K) in ‘Minshu No. 1’, ‘Xiazhai 65’, and ‘Qingshu No. 2’ potatoes. In conclusion, applying 7.2 g/L BIO three times during the seedling to post-bloom period is a potential strategy to enhance yield and quality for responsive early- and mid-maturing potato cultivars, offering a targeted solution for sustainable potato production.”.

 

Introduction When stating "In potatoes, pre-harvest foliar application of 10 g L-1 BIO extracted from seawater brown alga increased...", please specify which brown algae was used. Furthermore, you state that "no commercial practice of using BIO on potatoes has been well reported." Weren't the previously cited examples conducted on commercial varieties? Please clarify what you mean by "commercial." I also recommend expanding the introduction to better explain what biostimulants are, their mechanisms of action, and their application methods, including dosages and timings. Given that your work is entirely based on modifying these parameters, a more detailed background is essential.

Response: (1) The brown algae was Phaeophyceae. This information was added in revised MS. (2) We revised the commercial BIO application. Now the sentence was read as “despite these promising laboratory and small-scale field results, there is a lack of standardized, large-scale commercial protocols for using BIO on potatoes.”. (3) We further explained the BIO. Now the sentence was read as “BIO is a diverse group of materials with various origins (including microbial, plant, and seaweed extracts) and modes of action. Unlike traditional fertilizers, which provide essential nutrients, BIO enhances plant nutritional efficiency, improves tolerance to abiotic stress, and increases crop quality and yield ^[10]. Seaweed-based BIO, derived from Ascophyllum nodosum, Ecklonia maxima, Laminaria spp., and Sargassum, is among the most widely recognized and commercially available BIO. These extracts contain complex mixtures of natural compounds, including polysaccharides, phenolics, cytokinins, betaines, and trace elements ^[11-13]. The mechanisms of action of BIO include the stimulation of root development, enhancement of nutrient uptake efficiency, modulation of phytohormone balance, and activation of antioxidant defense systems to mitigate stress responses ^[14]. In agricultural practice, BIO is typically applied via foliar spraying or soil drenching. Foliar application is particularly popular due to its rapid absorption through the leaf cuticle and stomata, allowing for precise timing relative to critical growth stages ^[11-13].”.

 

Materials and Methods Potatoes were harvested between 85 and 135 days after planting. While this is inherently linked to the use of early, mid, and late-maturing cultivars, I suggest stating this relationship explicitly to avoid confusion. Regarding the biostimulant concentrations, please explain the rationale behind their selection. Do you suspect a direct fertilizing effect at such high concentrations? Other studies have reported excellent results using much lower biostimulant concentrations, such as 0.5 g/L. Please renumber the three experimental subsections as 2.2.1, 2.2.2, and 2.2.3. The experimental design is unclear, particularly the rationale for selecting different cultivars for each experiment. Please provide a stronger justification, as it is currently unclear why the same cultivars were not maintained across all trials. The sentence explaining that the early-maturing cultivar was selected for the subsequent experiment due to its high response to 7.2 g/L BIO should be moved directly into the Experiment 2 description. Additionally, the text block immediately preceding section 2.3 appears to be the caption or internal text of Figure 1; please format this properly to avoid it looking like a repetitive paragraph in the main text. I also suggest creating a comprehensive table to summarize all applied treatments, as the current text description is highly dispersive. In section 2.3, please format the weight-based categories clearly. Finally, in section 2.5, was there a minimum sprout length considered for the evaluation?

Response: (1) Revised, now the sentence was read as “Six potato cultivars were selected based on their maturity periods: early-maturing ‘Minshu No. 1’ (85 days to maturity), mid-maturing ‘Leshu No. 1’ (100 d to maturity) and ‘Xiazhai 65’ (110 d to maturity), and late-maturing ‘Qingshu No. 2’ (115 d to maturity), ‘Qingshu No. 10’ (120 d to maturity), and ‘Qingshu No. 9’ (135 d to maturity). Harvest times corresponded directly to these maturity indicators to ensure physiological comparability across treatments.”. (2) Explained. now the sentence was read as “The concentrations of 2.4 and 7.2 g/L were chosen based on Stimplex^® label reports indicating the effective minimum and maximum ranges for BIO application. These concentrations are well below levels typically required for direct fertilizing effects (which often require > 50 g/L for macronutrients), ensuring that observed effects are due to BIO rather than nutrient supply.”. (3) renumbered the three experimental subsections as 2.2.1, 2.2.2, and 2.2.3. Additionally, we explained the reason after 2.2. Experimental Designs.The Figure 1 was changed to Table 1. We thought it was more clear to show our experiments design. (4) Revised. Now, the sentence was read as “Sprouting incidence was determined after 7 d of storage at 20 °C and was defined as the percentage of tubers developing sprouts with a minimum length of > 2 mm.”.

 

 

Results Please check the formatting of all table captions, as they are currently disjointed. Furthermore, the statistical analysis approach is unclear. Why were statistics performed across all cultivars combined rather than individually within each cultivar? This raises questions about the primary rationale of the experiment: was it to evaluate whether biostimulants work, or to assess differences between cultivars? I strongly suggest performing the statistical analysis only within the same cultivar. This would yield more representative and meaningful information. By combining all cultivars, you risk masking important data and diminishing the significance of treatment effects relative to their specific controls.

Response: All table captions was revised. The data analysis was revised according to the comments.

 

Discussion In Section 4.1, you provide examples of biostimulant use on other species, such as sweet cherries and cucumbers. This requires a better introduction, as it is initially unclear why these examples are relevant to a study on potatoes. Furthermore, please clarify whether these cited studies used the exact same biostimulant or completely different formulations. It must also be noted that, by definition, biostimulants target abiotic stress, not biotic stress. Therefore, effects against fungal diseases cannot technically be classified as biostimulant activity. Regarding nutrient uptake, while you evaluated important macro- and micronutrients like K, Ca, Mg, Fe, and Zn, it is a pity that you did not investigate the uptake of other primary macronutrients, specifically Nitrogen and Phosphorus.

Response: Discussion was revised according to the comments. Also, the uptake of other primary macronutrients, specifically N and P, were added in the Discussion section 4.3.

 

Conclusions Given that you tested early, mid, and late-maturing cultivars, could you provide practical recommendations for biostimulant use based on these specific maturity profiles? Instead of merely summarizing the results, please provide a clear take-home message, moving beyond the already established fact that biostimulant efficacy varies according to multiple parameters. Finally, considering that the experimental fields were conventionally fertilized, what was the specific objective of biostimulation in this context? Generally, biostimulants are applied to counteract abiotic stress, improve yield in marginal or nutrient-poor soils, or reduce the overall application of standard fertilizers.

Response: We revised the Conclusion section. Now it was read as “This study demonstrated that the efficacy of BIO application was highly dependent on cultivar, spraying concentration, frequency, and timing. These findings proposed the following practical recommendations for potato growers: For early- and mid-maturing cultivars (i.e., ‘Minshu No. 1’, ‘Leshu No. 1’, and ‘Xiazhai 65’), pre-harvest application of 7.2 g/L BIO applied 3 to 4 times during critical developmental stages from seedling to 3 weeks after FB was recommended. This protocol significantly increased tuber yield, particularly of medium/large-sized tubers, and enhanced the accumulation of K, Fe, and Zn. Furthermore, this treatment maintained DMC and SC after storage and reduced post-harvest losses. For late-maturing cultivars (i.e., ‘Qingshu No. 9’ and ‘Qingshu No. 10’), no significant yield or quality response was observed to the tested BIO parameters. Therefore, a BIO application was not currently recommended for these late-maturing varieties. Growers should select responsive cultivars or alternative strategies if targeting late-maturing varieties. Although the experimental fields were conventionally fertilized, the primary goal was not to correct nutrient deficiencies but to optimize yield potential and tuber quality in a high-potential environment. In such well-managed systems, BIO served to enhance physiological efficiency, improve stress resilience, and elevate the nutritional quality of tubers beyond standard fertilization limits. This approach added value by extending shelf-life stability and enhancing nutrient density. Therefore, the BIO application should be viewed as a strategy for quality enhancement and yield improvement in responsive cultivars, rather than a substitute for standard agronomic practices. Despite these promising results, this study has certain limitations. The experiments were conducted under conventional fertilization conditions in Qinghai Plateau, which may limit the generalizability of the findings to other soil types or climatic zones. Additionally, the specific formulation of the BIO used (Stimplex^®) may yield different results with other seaweed extracts. Future research should address these limitations by investigating the uptake of N and P alongside micronutrients, exploring the molecular mechanisms underlying cultivar-specific responses, conducting multi-year, multi-location field trials to validate the stability of these findings under diverse environmental conditions, and assessing the long-term nutritional impact of increased micronutrient uptake on human health.”.

 

Reviewer’s comments on this manuscript have been considered and corrected accordingly.

 

Thank you for the opportunity to improve the MS. I will look forward to your reply. Please do not hesitate to contact me should you request additional information.

 

Sincerely

 

Yu Dong,

Qinghai University

Qinghai Academy of Agriculture and Forestry Sciences

No. 253 Ningda Road

Xining, Qinghai 810016, China

Email address: yu.dong@qhu.edu.cn; dongyu8306@hotmail.com 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript has been substantially improved.

I still have one remark regarding the following sentence: « Minshu No. 1’ potatoes, 3-time applications of 9.6 g/L BIO and spraying 7.2 g/L BIO 4 times ………weight was not affected » in lines 292-294. In Table 6, I noticed that three applications of 7.2 g/L BIO also had a significant effect on the weights of small and large tubers. Therefore, the above sentence should be corrected accordingly.

Author Response

Thank you for your review of our manuscript, “Pre-Harvest Seaweed Biostimulant Applications: Optimizing Concentration, Timing, and Frequency for Cultivar-Specific Improvements in Potato Yield and Quality” (ID: horticulturae-4370967). We have thoroughly read the comments from the review team and revised the manuscript accordingly. Please find our point-by-point explanation in red to each of the comments raised by the team below.

 

I still have one remark regarding the following sentence: « Minshu No. 1’ potatoes, 3-time applications of 9.6 g/L BIO and spraying 7.2 g/L BIO 4 times ………weight was not affected » in lines 292-294. In Table 6, I noticed that three applications of 7.2 g/L BIO also had a significant effect on the weights of small and large tubers. Therefore, the above sentence should be corrected accordingly.

Response: Revised. Now, the sentence was read as “For the harvest evaluation (Table 6), applications of BIO at 7.2 (3 or 4 times) or 9.6 (3 times) g/L did not affect RSC or medium tuber weight, but significantly increased the TY, medium/large tuber weight DMC, and SC in ‘Minshu No. 1’ potatoes, with no significant difference among the BIO treatments. For ‘Xiazhai 65’ potatoes, all BIO treatments increased TY, medium/large tuber weight, DMC, and SC, but did not affect small tuber weight or RSC.”.

 

Reviewer’s comments on this manuscript have been considered and corrected accordingly.

 

Thank you for the opportunity to improve the MS. I will look forward to your reply. Please do not hesitate to contact me should you request additional information.

 

Sincerely

 

Yu Dong,

Qinghai University

Qinghai Academy of Agriculture and Forestry Sciences

No. 253 Ningda Road

Xining, Qinghai 810016, China

Email address: yu.dong@qhu.edu.cn; dongyu8306@hotmail.com 

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for responding to my comments. The paper may be published as present form.

Author Response

Thank you for your review of our manuscript, “Pre-Harvest Seaweed Biostimulant Applications: Optimizing Concentration, Timing, and Frequency for Cultivar-Specific Improvements in Potato Yield and Quality” (ID: horticulturae-4370967). We have thoroughly read the comments from the review team and revised the manuscript accordingly. Please find our point-by-point explanation in red to each of the comments raised by the team below.

 

Thank you for responding to my comments. The paper may be published as present form.

Response: Thank you! We are very appreciative of your work.

 

Reviewer’s comments on this manuscript have been considered and corrected accordingly.

 

Thank you for the opportunity to improve the MS. I will look forward to your reply. Please do not hesitate to contact me should you request additional information.

 

Sincerely

 

Yu Dong,

Qinghai University

Qinghai Academy of Agriculture and Forestry Sciences

No. 253 Ningda Road

Xining, Qinghai 810016, China

Email address: yu.dong@qhu.edu.cn; dongyu8306@hotmail.com 

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript has been deeply revised. The authors followed reviewers comment properly. I have no other comments. The manuscript is ready for publication.

Author Response

Thank you for your review of our manuscript, “Pre-Harvest Seaweed Biostimulant Applications: Optimizing Concentration, Timing, and Frequency for Cultivar-Specific Improvements in Potato Yield and Quality” (ID: horticulturae-4370967). We have thoroughly read the comments from the review team and revised the manuscript accordingly. Please find our point-by-point explanation in red to each of the comments raised by the team below.

 

The manuscript has been deeply revised. The authors followed reviewers comment properly. I have no other comments. The manuscript is ready for publication.

Response: Thank you! We are very appreciative of your work.

 

Reviewer’s comments on this manuscript have been considered and corrected accordingly.

 

Thank you for the opportunity to improve the MS. I will look forward to your reply. Please do not hesitate to contact me should you request additional information.

 

Sincerely

 

Yu Dong,

Qinghai University

Qinghai Academy of Agriculture and Forestry Sciences

No. 253 Ningda Road

Xining, Qinghai 810016, China

Email address: yu.dong@qhu.edu.cn; dongyu8306@hotmail.com