Enhancing Drought Tolerance and Water Productivity of Diverse Maize Hybrids (Zea mays) Using Exogenously Applied Biostimulants under Varying Irrigation Levels

Round 1

Reviewer 1 Report

The authors have examined the role of biostimulants in mitigating the adverse effect of drought stress in maize hybrids. I have critically reviewed the manuscript and found that the experimental results and objectives of the study are scientifically sound and contribute novel knowledge to the agronomists. Therefore, I recommend a major review of this manuscript. My concerns are below!

 

1.       Why did the authors choose mild (75% ET) and severe (50% ET) drought stress levels? Is there any scientific base for choosing 75% and 50% ET levels? What is ET? Can the authors explain this trait in the methods section?

2.       The title of the manuscript seems rough and it can be changed to clearly shed light on the objective of the research. “Hybrids” of what? Confusing.

3.       The scientific language is full of flaws and needs to be revised by a native speaker.

4.       There is no basis provided for the selection of the biostimulants dosages used in the current experiment.

5.       The results are poorly presented in the Abstract section. Abstract seems like an introduction.

6.       The key words are not appropriate, which should be short and concise.

7.       The introduction and discussion should explain some mechanistic insights related to the role of biostimulants against drought and following recent researches can help you to find some of them, and their citation would enhance the impact of this work.

https://doi.org/10.3389/fpls.2022.945256

https://doi.org/10.3389/fpls.2022.850567

8.       In the figures, statistical significance levels / differences has not been presented in terms of lettering and I understand that because of a lot of data, there might be a crowdy presentation of figures with lettering and then it would make more complexity to understand. My suggestion is that, only put an asterisk on the highly significant bars depending on your P value.

 

9.       The conclusion sections needs amendments according to the results. 

Author Response

Dear Editor,

We would like to thank you and the reviewers for the time and efforts devoted to our manuscript entitled “Integrated Use of Exogenously Applied Biostimulants and Drought Tolerant Hybrids Enhances Maize Production and Water Productivity under Varying Irrigation Levels” (agronomy-2322433). We have revised the manuscript according to the comments and suggestions pointed out by the reviewers. We have addressed the comments of the reviewers in a point-by-point below in red color; in addition, we have highlighted all the associated changes made to the manuscript using track changes.

Yours sincerely,

Authors

Reviewers' Comments

Reviewer #1

The authors have examined the role of biostimulants in mitigating the adverse effect of drought stress in maize hybrids. I have critically reviewed the manuscript and found that the experimental results and objectives of the study are scientifically sound and contribute novel knowledge to agronomists. Therefore, I recommend a major review of this manuscript. My concerns are below!

Re: We would like to thank the Reviewer for his time dedicated to our manuscript and his positive assessment and feedback on our work.

1. Why did the authors choose mild (75% ET) and severe (50% ET) drought stress levels? Is there any scientific base for choosing 75% and 50% ET levels? What is ET? Can the authors explain this trait in the methods section?

   Re: The applied irrigation regimes were applied based on estimated crop evapotranspiration (ET) proved by FAO Penman-Monteith equation. Daily meteorological data including minimum and maximum temperatures, dew point temperature and wind speed, were obtained from a weather station located at the experimental site and were used for calculating ET. The determined full irrigation requirement (100% ET) was reduced by 25% to apply the mild drought stress (75% ET) and  50% to apply severe drought stress (50% ET). More details have been added to Ms&Ms as suggested, please see lines 126-136.

2. The title of the manuscript seems rough and it can be changed to clearly shed light on the objective of the research. “Hybrids” of what? Confusing.

  Re: The title has been improved as requested to be “Enhancing Drought Tolerant and Water Productivity of Diverse Maize Hybrids using Exogenously Applied Biostimulants under Varying Irrigation Levels”

3. The scientific language is full of flaws and needs to be revised by a native speaker.

  Re: The manuscript has been revised by our friend Dr. Ahmed Omar at Florida University

4. There is no basis provided for the selection of the biostimulants dosages used in the current experiment.

  Re: Corresponding references have been added as suggested (lines 142 and 150)

5. The results are poorly presented in the Abstract section. Abstract seems like an introduction.

Re: The abstract has been rewritten and improved as requested

6. The keywords are not appropriate, which should be short and concise.

  Re: The keywords have been revised and improved as requested

7. The introduction and discussion should explain some mechanistic insights related to the role of biostimulants against drought and following recent research can help you to find some of them, and their citation would enhance the impact of this work.

https://doi.org/10.3389/fpls.2022.945256

https://doi.org/10.3389/fpls.2022.850567

Re: The mechanistic insights related to the role of biostimulants against drought stress have been clarified in the introduction in lines 83-95 and in the discussion in lines 404-422, 429-438, 459-467, also new references have been added as requested.

8. In the figures, statistical significance levels/differences have not been presented in terms of lettering and I understand that because of a lot of data, there might be a crowdy presentation of figures with lettering and then it would make it more complexity to understand. My suggestion is that only put an asterisk on the highly significant bars depending on your P value.

  Re: Thanks for understanding the difficulty of presenting letters of significance in Figures 1-3 due to the abundance of presented data. Alternative to that, the presented bars on the top of columns correspond to the least significant difference (LSD). The height of LSD bars indicates significant differences among treatments. As if the difference between two treatments is outside the LSD bar, hence these treatments are significantly different.

9. The conclusion section needs amendments according to the results.

   Re: The conclusion has been revised and improved as requested 

We greatly appreciate the careful review which considerably assisted in improving the manuscript.

Reviewer 2 Report

To whom it may concern,

I am delighted to review this paper. The physiological basis and the agronomical consequences of the biostimulant application are research topics that have become increasingly emergent in the last time. The use of new hybrids in combination with biostimulant application under stressful conditions sounds like a great solution to deal with the following environmental threats. 

Unfortunately, at this point of the review process, I advise the authors to make the results more straightforward and understandable, avoiding citing just the literature. In addition, it would be good to explain the meaning of the letters used in the formula. For example, in the RWC formula, please explain what FW, TW, and DW mean. 

The statistical analysis expressed in the table is transparent. Unfortunately, I strongly advise putting the post-doc letters in all the figures to be more precise and more straightforward. Without those, I cannot determine the differences in the agronomical and physiological parameters analyzed between the hybrids under control conditions and moringa seed extract and ɑ-Tocopherol treatments.

I am looking forward to receiving your paper back as soon as possible.

Author Response

Dear Editor,

We would like to thank you and the reviewers for the time and efforts devoted to our manuscript entitled “Integrated Use of Exogenously Applied Biostimulants and Drought Tolerant Hybrids Enhances Maize Production and Water Productivity under Varying Irrigation Levels” (agronomy-2322433). We have revised the manuscript according to the comments and suggestions pointed out by the reviewers. We have addressed the comments of the reviewers in a point-by-point below in red color; in addition, we have highlighted all the associated changes made to the manuscript using track changes.

Yours sincerely,

Authors

Reviewer #2

I am delighted to review this paper. The physiological basis and the agronomical consequences of the biostimulant application are research topics that have become increasingly emergent in the last time. The use of new hybrids in combination with biostimulant application under stressful conditions sounds like a great solution to deal with the following environmental threats. At this point of the review process, I advise the authors to make the results more straightforward and understandable, avoiding citing just the literature. In addition, it would be good to explain the meaning of the letters used in the formula. For example, in the RWC formula, please explain what FW, TW, and DW mean. The statistical analysis expressed in the table is transparent. I strongly advise putting the post-doc letters in all the figures to be more precise and more straightforward. Without those, I cannot determine the differences in the agronomical and physiological parameters analyzed between the hybrids under control conditions and moringa seed extract and ɑ-Tocopherol treatments.

I am looking forward to receiving your paperback as soon as possible.

 

Re: We would like to thank the Reviewer for his time dedicated to our manuscript and his positive assessment and feedback on our work. The results have been revised as suggested and improved, the letters in the used formula of RWC have been clarified (lines 163-165). But presenting post-doc letters in Figures 1-3 is difficult due to the abundance of presented data. Alternative to that, the presented bars on the top of columns correspond to the least significant difference (LSD). The height of LSD bars indicates significant differences among treatments. As if the difference between two treatments is outside the LSD bar, hence these treatments are significantly different.

Reviewer 3 Report

It is imperative to describe the effect of the year on the results. Remember, that one of the main objectives is the effect of drought. There are other observations in the document. There are many very old references.

Comments for author File: Comments.pdf

Author Response

Dear Editor,

We would like to thank you and the reviewers for the time and efforts devoted to our manuscript entitled “Integrated Use of Exogenously Applied Biostimulants and Drought Tolerant Hybrids Enhances Maize Production and Water Productivity under Varying Irrigation Levels” (agronomy-2322433). We have revised the manuscript according to the comments and suggestions pointed out by the reviewers. We have addressed the comments of the reviewers in a point-by-point below in red color; in addition, we have highlighted all the associated changes made to the manuscript using track changes.

Yours sincerely,

Authors

Reviewer #3

It is imperative to describe the effect of the year on the results. Remember, that one of the main objectives is the effect of drought. There are many very old references.

Re: We would like to thank the Reviewer for his time dedicated to our manuscript and his positive assessment and feedback on our work. The effect of the growing season has been clarified in lines 193-200 and 384-389. The typical summer growing season in Egypt is described with no rainfall events as presented in lines 106-110 and Table S1.

 The old references belong to the applied methodology as Arnon 1949 for the determination of chlorophyll and carotenoid contents, Maxwell and Johnson 2000 for photosynthetic efficiency, Jagendorf 1956 and Avron 1960 for photochemical activity, Premachandra 1989 for membrane stability index, Barrs and Weatherley 1962 for relative water content, Heath and Packer 1968 for Malondialdehyde content, Sullivan 1979 for Electrolyte leakage, Bates 1973 for proline content, Irigoyen 1992 for soluble sugars content, Vitória 2001 for preparing enzyme extraction, Chance 1955 for catalase and peroxidase activities, Foster 1980 for superoxide dismutase, Allen 1998 for FAO Penman-Monteith equation, Makkar and Becker 1996 for preparation moringa extract, Burton and Devane 1953 and Dewey and Lu 1959 for Path analysis and genetic variability. 

Otherwise, the references have been updated to be 3 references in 2023, 14 references in 2022, 10 in 2021, 3 in 2020, 6 in 2019, 4 in 2018, 6 in 2017, 3 in 2016, 3 in 2014, 3 in 2013, 1 in 2012, and 1 in 2009.

There are other observations in the document.

Re: All observations in the document have been addressed as presented below:

 

Line 21: Scientific name of moringa

Re: The scientific name has been added as suggested (line 25 in the revised version)

Line 23: Here it is important to add each description of treatments and experimental design

Re: More details have been added as requested (lines 28-35)

Line 37: Please each one in alphabetical order.

Re: The keywords have been reordered as requested

Line 48: , and physiological plant functions,

Re: added as requested (line 68)

Line 58: What kind of substances? chemicals, organics, ???

Re: corrected as suggested (line 79)

Line 60: Scientific name

Re: The scientific name has been added (line 81)

Line 90: Typically, the corn crop needs about 85 to 100 days to appear at the panicle stage. I do not understand this text.

Re: Maize reaches tasseling stage in Egypt after about 60 days after sowing, therefore the farmers end the N fertilization before that time. The 0sentence has been clarified (lines 116-117), “Nitrogen fertilizer was performed at a rate of 300 kg N/ha as ammonium sulfate (21% N) as fertigation in six splits at 8-day intervals after sowing.”  

Line 93: delete (Zea mays)

Re: Done (line 119)

Line 96: applications of moringa and...

Re: Done (line 122)

Line 97: Please add each name of the hybrids [..]

Re: Done (line 123)

Line 108: Consider adding the average climate with the two current seasons [temperatures (maximum and minimum), relative humidity and rainy seasons]

Re: Meteorological information has been added as suggested (lines 108-111).

Line 114: common name

Re: Done (line 144)

Line 146: How many days after seeding? Please include it  [...].

Re: Added (line 179)

Line 158: Please define that season was the random factor, and the others, the fixed factors.

Re: Done (lines 195-200)

Line 166: Because of the majority of statistical analysis, there are interactions, the discussion should be done in this scene. Discussion separately is not recommended.

Re: The interaction effect has been considered in the discussion section (lines 501-522).

Table 1:  Replace Gs with gs

Re: Done (line 233)

Line 320: Capital letter

Re: Done (line 368)

Line 347: But, it was tested? Or is a hypothesis?

Re: Yes, moringa seed extract was analyzed and its analysis is presented in Supplementary Table 1.

Line 350: Where is this table?

Re: Tables S1 and Table S2 are presented as supplementary materials

Line 445: Yes of course, but, the interactions between main treatments, is imperative. On the other hand, the article is repetitive in mention of drought, but, the effect of each year is not explained. One reason for including the effect of weather is that drought is one thing and water restriction is another. The climate includes high temperatures and lack of rainwater, and water restriction does not.

Re: The interaction effect has been considered in the discussion section (lines 495-515). The typical summer growing season in Egypt is described with no rainfall events as presented in Table S1. More information has been added on weather conditions in lines 106-111 and 378-384.

21% of references are "obsolete or outdated"

Re: All highlighted references in the reference list belong to the applied methodology as Arnon 1949 for the determination of chlorophyll and carotenoid contents, Maxwell and Johnson 2000 for photosynthetic efficiency, Jagendorf 1956 and Avron 1960 for photochemical activity, Premachandra 1989 for membrane stability index, Barrs and Weatherley 1962 for relative water content, Heath and Packer 1968 for Malondialdehyde content, Sullivan 1979 for Electrolyte leakage, Bates 1973 for proline content, Irigoyen 1992 for soluble sugars content, Vitória 2001 for preparing enzyme extraction, Chance 1955 for catalase and peroxidase activities, Foster 1980 for superoxide dismutase, Allen 1998 for FAO Penman-Monteith equation, Makkar and Becker 1996 for preparation moringa extract, Burton and Devane 1953 and Dewey and Lu 1959 for Path analysis and genetic variability.  

Otherwise, the references have been updated to be 3 references in 2023, 14 references in 2022, 10 in 2021, 3 in 2020, 6 in 2019, 4 in 2018, 6 in 2017, 3 in 2016, 3 in 2014, 3 in 2013, 1 in 2012, and 1 in 2009.

We greatly appreciate the careful review which considerably assisted in improving the manuscript.   

Round 2

Reviewer 1 Report

The authors have improved and addressed all the queries raised during the first revision. I am satisfied with the quality of the manuscript. 

 

It can be accepted now.

Reviewer 3 Report

No comments