Effect of Chitosan-Poly(Acrylic Acid) Complexes and Two Nutrient Solutions on the Growth and Yield of Two Habanero Pepper Cultivars

Round 1

Reviewer 1 Report

Overall Comments: It is a very well-designed study and the authors have taken significant efforts to present their research findings concisely. The use of nutrient combination is of utmost importance for researchers that conduct their research in greenhouses and I think this study may help peer pepper researchers in addressing this issue. However, there is a weakness of this study and it is that only two accessions have been included to evaluate the effect of CS-PAA and nutrient solutions. For breeders, genetic background is a very important part of crop improvement and this study has left this space to some extent. Additionally, there are minor issues of inappropriate use of commas in connecting words so the author needs to do these minor corrections to further consider this manuscript. Please see more comments in the attached review report.

Comments for author File: Comments.pdf

Author Response

Appreciable reviewer we send the answers to your comments. Thank you for your valuable time invested in reviewing our manuscript.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript is scientifically interesting and offers a wide evaluation of how chitosan applications and nutrient solutions affect the most relevant quantitative and qualitative parameters in two cultivars of Habanero Pepper.
The introduction covers the most important topics that were evaluated in the trials.
The Materials and method are detailed and both the experimental design and the number of evaluations done give power to the manuscript.
Results, discussions, and conclusions are appropriate.
I just invite the authors to:
-Line 34: better explain why the deacetylation process is considered inexpensive (respect what and why).
-Subchapter 2.2: I kindly invite the authors to add a table that summarizes the concentration and/or dilution of the foliar applications to better communicate that precious info as done for the nutrient solutions.
-Lines 109-111: please add the phenological phase (e.g. in BBCH) for the first and last foliar application.
-Lines 124-124: please add details about the application of the nutrient solution: e.g moment of the day, use of the drainage.

Author Response

Appreciable reviewer we send the answers to your comments. Thank you for your valuable time invested in reviewing our manuscript.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have made the recommended corrections and have responded to the comments reasonably well. I have no further comments.

Author Response

Thank you

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Effect of Chitosan-Polyacid Complex on the Growth, Yield, and 2 Fruit Quality of Habanero Peppers Irrigated with Two Differ-3 ent Nutrient Solutions 

The study offers interesting results about the Chitosan-plyacid complex effects on two capsicum species. 

Some suggestions are in the document annexed.

Comments for author File: Comments.pdf

Author Response

1. Introduction

In introduction I suggest including more information about the effect of Chitosan and Poly (AcrylicAcid) on the growth of capsicum or other crops to support the effect of the two components. It because the authors mention with more emphasis other effects than the growth or fruits of the two components.

Answer: In lines 55-58 we add information on the effect of chitosan and polyacrylic acid on plant growth.

2. Materials and Methods

2.1. Establishment of the Experiment

Please add the experimental design of the experiment, how many plants were measure for the different parameters. It was the same number of plants measure for each parameter?

Answer: In lines 116-118 we add the experimental design and number of plants.

2.2 Synthesis of the Non-Stoichiometric Interpolyelectrolyte CS–PAA Complexes

How were determined the chitosan alone (CS), Poly(Acrylic Acid) (PAA), 100 and the chitosanPoly(Acrylic Acid) doses? For the treatments? Explain in this part.

Answer Answer: In lines 102-104 we add, based on previous works, we observed that at low concentrations polyions (CS and PAA) have a better inductive (or biostimulant) effect in plant tissues, Ortega-Ortiz et al. [11] and Cabrera-De la Fuente et al. [14].

2.3 Treatment define NSB and NSA treatments

Mention if at what time chitosan alone (CS), Poly(Acrylic Acid) (PAA), 100 and the chitosan-Poly(Acrylic Acid) complex. + were added to the Steiner’s solution to stablish treatments.

Answer: In lines 115-116, we inform that foliar applications were added to each nutrient solution with a manual sprayer eight times during the experiment at 15-day intervals after transplantation. The total volume of the foliar application was 120 mL per plant.

2.3. Growth and Yield Parameters

Mention if only one yield was obtained.

Answer: In lines 133-134, we add that only one yield per plant was obtained, determined by the accumulation of the fresh weight of the fruits harvested during the crop cycle.

2.4. Fruit Quality

Please mention why the authors decided to evaluate the parameters of quality and no others. Add bibliography documents that support this.

Answer: Line 132-133. Answer: In lines 132-133, we add that the fruit quality parameters were evaluated to determine the effect pre-harvest of the CS-PAA complex [25] and the K⁺/Ca²⁺ ratio of the nutrient solutions [26].

2.5. Statistical Analysis

In this section was found the experimental design and number of plants per treatment, I suggested to added in material section.

Answer: The experimental design and the number of plants per treatment was moved to the materials section.

Please clarify if statistical analysis of each pepper species were analyzed as independent way

Answer: In line 151 we clarified the statistical analysis as independent way

3. Results

3.1. Plant Height, 3.2. Stem Diameter

I suggested to use the same subtitles from methodology and results

Answer: We Corrected the subtitles

3.8. Titratable Acid (TA)

213 change the Spanish word ¨la¨

Answer: Corrected

4. Discussion

Ravi Kumar [26] reports that chitosan is 6.89% nitrogen The sentence seems to be isolated, there’s no explanation or connection with the prior or after text.

Answer: In lines 249-250 we correct this sentence

Reviewer 2 Report

Line 47 'useful life', do you mean 'shelf life'? 

Line 64 'most research on has...' grammar error

The introduction can explain why the study was conducted under two nutrient solutions.

 

Line 96 & 114: why are there two 2.3 for the subheading number?

Line 135: why 3 replications for the fruit quality data analysis when you used 10 fruit to collect the fruit quality data?

Line 187:  NSA+CS–PAA (ab) was not higher than the treatment NSA+water (bc)

Line 212: what is 'La TA'?

Line 213: 'la the majority'?

Line 226-228: here is one example when p for the ripe fruit = 0.2958, a conclusion should be made as no difference among the treatments. No multiple comparisons should be performed

(there are quite a few similar issues in the results, when p is >0.05, multiple comparisons should not be performed, and the conclusion should be no difference among treatments)

Lines 230-232: p=0.2368 for ripe fruit, therefore, there were no differences among treatments

Lines 234-237: p was > 0.05 for both green and ripe fruits. Therefore, there were no differences among treatments

 

Line 260: 'y number'??

Author Response

Line 47 'useful life', do you mean 'shelf life'?

Anwer: Corrected

Line 64 'most research on has...' grammar error

Answer: Corrected

The introduction can explain why the study was conducted under two nutrient solutions.

Answer: In lines 65-67 we added study on nutritive solutions in Mexico

Line 96 & 114: why are there two 2.3 for the subheading number?

Answer: Corrected

Line 135: why 3 replications for the fruit quality data analysis when you used 10 fruit to collect the fruit quality data?

Answer: In line 155 we clarify that are ten replicates

Line 187:  NSA+CS–PAA (ab) was not higher than the treatment NSA+water (bc)

Answer: Corrected

Line 212: what is 'La TA'?

Answer: Corrected “The TA”

Line 213: 'la the majority'?

Answer: Corrected

Line 226-228: here is one example when p for the ripe fruit = 0.2958, a conclusion should be made as no difference among the treatments. No multiple comparisons should be performed (there are quite a few similar issues in the results, when p is >0.05, multiple comparisons should not be performed, and the conclusion should be no difference among treatments)

Lines 230-232: p=0.2368 for ripe fruit, therefore, there were no differences among treatments

Lines 234-237: p was > 0.05 for both green and ripe fruits. Therefore, there were no differences among treatments

Answer: Based on his comments and the suggestion of the academic editor, we analyzed foliar applications and nutritional solutions as factors. We did a two-way analysis of variance as explained on lines 151-152. We do not perform multiple comparisons when p> 0.05.

Line 260: 'y number'??

Answer: Corrected

Reviewer 3 Report

Introduction:

It would be nice to add fertigation information for the pepper production in Mexican and explain why you used two different nutrient solutions  in this study.

• Line 50: Delete “on the other hand”.
• Line 58: It is considered “as” an economical… add “as”.
• Line 60: Delete the two “as” and “for”.
• Line 64: Change it to “Most of the published studies have focused on ….”

M&M:

• Line 100-103: Why there is no control (water) in the evaluated treatments?
• Is the study a RCBD? How many replications?

 Results and Discussions:

Your presentation is clear but the results are not convincing without the control in the study. That's the major problem.

• Line 225: un-bold the first sentence.

Author Response

Introduction:

It would be nice to add fertigation information for the pepper production in Mexican and explain why you used two different nutrient solutions  in this study.

Answer: Line 61-63. Information about fertigation in Mexico was added and it was justified because they used two nutrient solutions.

Line 50: Delete “on the other hand”.

Answer: Eliminated

Line 58: It is considered “as” an economical… add “as”.

Answer: Corrected

Line 60: Delete the two “as” and “for”.

Answer: Corrected

Line 64: Change it to “Most of the published studies have focused on ….”

Answer: Corrected

M&M:

Line 100-103: Why there is no control (water) in the evaluated treatments?

Is the study a RCBD? How many replications?

Answer: If there is a control (water) in the treatments, it is explained in lines 110-114. The design of the experiment and the replicates are reported in lines 116-118.

 Results and Discussions:

Your presentation is clear but the results are not convincing without the control in the study. That's the major problem.

Answer: If there is a control (water) in the treatments, it is explained in lines 110-114.

Line 225: un-bold the first sentence.

Answer: Sentence removed  

Reviewer 4 Report

The work presents the results of an experiment in a hydroponic system on the effect of foliar application of Chitosan- Poly(Acrylic Acid) complex (CS–PAA) on the growth, yield, and fruit quality of two habanero pepper cultivars irrigated with two nutrient solutions (A and B) in the greenhouse.

The work is interesting although the explanation of the biostimulating mechanism of action is lacking. It would be interesting to reconfirm these data by repeating the experiment and try to explain the phenomenon.

It is also not well justified to use two very similar nutrient solutions despite having found an interaction between the Jaguar variety and the nutrient solution B. Furthermore, I would like to point out that in Table 1 the sum of the percentages of the cations and that of the anions reaches 102.5%.

Regarding the hydroponic system, there is talk of '40 x 40 cm black polyethylene bags filled with river sand' and 'direct watering system' but it has not been clarified:

• whether watering was manual (as I suppose) or automatic,
• what was the volume of irrigation,
• if irrigation produced the run off and how this was disposed of without interfering with that of neighboring plants (3 plants / m²) generating a mixture that by sub-irrigation could go up and reduce the differences between the solutions.

Check English, in the title and in other parts of the text the use of different (eg different nutrient solutions or different samples on line 130, etc.) is unnecessary. Some small oversight in Spanish at lines 181 and 241 (de), 213 (la) and 260 (y).

Author Response

The work presents the results of an experiment in a hydroponic system on the effect of foliar application of Chitosan- Poly(Acrylic Acid) complex (CS–PAA) on the growth, yield, and fruit quality of two habanero pepper cultivars irrigated with two nutrient solutions (A and B) in the greenhouse.

The work is interesting although the explanation of the biostimulating mechanism of action is lacking. It would be interesting to reconfirm these data by repeating the experiment and try to explain the phenomenon.

Answer: The hypothesis of the biostimulant mechanism of action on growth and performance is explained in the discussion. We modify the statistical analysis, we use a two-way analysis of variance. The effect of CS-PAA complex on growth and yield is clear in the two cultivars of habanero pepper used, showing its biostimulation capacity.

It is also not well justified to use two very similar nutrient solutions despite having found an interaction between the Jaguar variety and the nutrient solution B. Furthermore, I would like to point out that in Table 1 the sum of the percentages of the cations and that of the anions reaches 102.5%.

Answer: The difference of the two nutritive solutions is in the relationship between potassium and calcium, the NSA has a relationship of 0.83 and the NSB has a relationship of 1.2. Indeed the sum of the cations and anions is 102.5%. There are studies such as those of Hernández-Peréz et al. where they have used up to 120%. Hernández-Pérez, O.I.; Valdez-Aguilar, L.A.; Alia-Tejacal, I.; Cartmill, A.D.; Cartmill, D.L. Tomato Fruit Yield, Quality, and Nutrient Status in Response to Potassium: Calcium Balance and Electrical Conductivity in the Nutrient Solution. Journal of Soil Science and Plant Nutrition 2020, 20, doi:10.1007/s42729-019-00133-9.

Regarding the hydroponic system, there is talk of '40 x 40 cm black polyethylene bags filled with river sand' and 'direct watering system' but it has not been clarified:

whether watering was manual (as I suppose) or automatic, what was the volume of irrigation, if irrigation produced the run off and how this was disposed of without interfering with that of neighboring plants (3 plants / m2) generating a mixture that by sub-irrigation could go up and reduce the differences between the solutions.

Answer: These details have been clarified in section 2.1

Check English, in the title and in other parts of the text the use of different (eg different nutrient solutions or different samples on line 130, etc.) is unnecessary. Some small oversight in Spanish at lines 181 and 241 (de), 213 (la) and 260 (y).

Answer: Corrected

Reviewer 5 Report

   The article “Effect of Chitosan-Polyacid Complex on the Growth, Yield, and Fruit Quality of Habanero Peppers Irrigated with Two Different Nutrient Solutions” was investigated by Palacios-Torres et al. to provide the effect of foliar applications of Chitosan-Poly(Acrylic Acid) complexes(CS-PAA) on horticultural traits such as the growth, yield, and fruit quality of habanero peppers with two different nutrient irrigations (solution A and B) in greenhouse.

   The authors provided that the application of CS-PAA complexes enhanced the evaluated traits such as height, stem diameter, and the number of fruits with solution A and B in both two peppers except for the Jaguar variety irrigated with solution B. As well as, the CS-PAA complexes influenced the increments of the ratio of soluble solids to titratable acid in the ripe fruits.

    In general, the experimental design was properly conducted with hydroponic system in greenhouse condition. However, it seemed like the authors provided the insufficient analysis of the experimental data for publication and should extensively improve their results with adequate statistical analysis, interpretation, and explanations in main contexts and figure legends. In addition to this, the introduction, the discussion, and the English should be more improved with previous researches, publications, and correct grammar and spelling.

Author Response

The article “Effect of Chitosan-Polyacid Complex on the Growth, Yield, and Fruit Quality of Habanero Peppers Irrigated with Two Different Nutrient Solutions” was investigated by Palacios-Torres et al. to provide the effect of foliar applications of Chitosan-Poly(Acrylic Acid) complexes(CS-PAA) on horticultural traits such as the growth, yield, and fruit quality of habanero peppers with two different nutrient irrigations (solution A and B) in greenhouse.

The authors provided that the application of CS-PAA complexes enhanced the evaluated traits such as height, stem diameter, and the number of fruits with solution A and B in both two peppers except for the Jaguar variety irrigated with solution B. As well as, the CS-PAA complexes influenced the increments of the ratio of soluble solids to titratable acid in the ripe fruits.

    In general, the experimental design was properly conducted with hydroponic system in greenhouse condition. However, it seemed like the authors provided the insufficient analysis of the experimental data for publication and should extensively improve their results with adequate statistical analysis, interpretation, and explanations in main contexts and figure legends. In addition to this, the introduction, the discussion, and the English should be more improved with previous researches, publications, and correct grammar and spelling.

Answer: According to your suggestion, we carry out the statistical analysis including nutrient solutions and foliar applications as factors. We use a two-way analysis of variance. The introduction, discussion and English we improved.

Round 2

Reviewer 3 Report

The manuscript has been improved, yet the missing control still is the major problem. All the parameters in your figures should include "water spray" (control) so that we can see what the difference between the control and the treatments. Table 1 and 5 gave us some information for the control, but not enough. In your M&M, you should clearly mention your control and include into the treatments. Also, for all the data analysis, you should include all the data from the control and make comparisons accordingly. 

Author Response

The manuscript has been improved, yet the missing control still is the major problem. All the parameters in your figures should include "water spray" (control) so that we can see what the difference between the control and the treatments. Table 1 and 5 gave us some information for the control, but not enough. In your M&M, you should clearly mention your control and include into the treatments. Also, for all the data analysis, you should include all the data from the control and make comparisons accordingly. 

Dear reviewer, regarding your comments we reply that:

We include the control (water spray) in M&M and figures. For the data analysis, we made the comparisons of the treatments with respect to the control. In this experiment we did not include a control where it was irrigated with water and sprayed with water, because it was carried out in a hydroponic system and not in soil. In a hydroponic system, the nutrient absorption of the plants depends on the fertilizers added to the nutrient solution.

Reviewer 4 Report

Answer: The difference of the two nutritive solutions is in the relationship between potassium and calcium, the NSA has a relationship of 0.83 and the NSB has a relationship of 1.2. Indeed the sum of the cations and anions is 102.5%. There are studies such as those of Hernández-Peréz et al. where they have used up to 120%. Hernández-Pérez, O.I.; Valdez-Aguilar, L.A.; Alia-Tejacal, I.; Cartmill, A.D.; Cartmill, D.L. Tomato Fruit Yield, Quality, and Nutrient Status in Response to Potassium: Calcium Balance and Electrical Conductivity in the Nutrient Solution. Journal of Soil Science and Plant Nutrition 2020, 20, doi:10.1007/s42729-019-00133-9.

The sum of cations in meq/L must be equal to the sum of anions in meq/L as is in table 1 of the paper that you have cited. Therefore, it would be better in Table 2 to express the sources of macronutrients in meq / L and not in g / L.

Answer: The hypothesis of the biostimulant mechanism of action on growth and performance is explained in the discussion. We modify the statistical analysis, we use a two-way analysis of variance. The effect of CS-PAA complex on growth and yield is clear in the two cultivars of habanero pepper used, showing its biostimulation capacity.

The work is interesting although the explanation of the biostimulating mechanism of action is lacking. It would be interesting to reconfirm these data by repeating the experiment and try to explain the phenomenon. I hope that you will continue to work on this topic until you verify the hypothesis you have proposed.

Author Response

The sum of cations in meq/L must be equal to the sum of anions in meq/L as is in table 1 of the paper that you have cited. Therefore, it would be better in Table 2 to express the sources of macronutrients in meq/L and not in g / L.

The work is interesting although the explanation of the biostimulating mechanism of action is lacking. It would be interesting to reconfirm these data by repeating the experiment and try to explain the phenomenon. I hope that you will continue to work on this topic until you verify the hypothesis you have proposed.

Dear reviewer, regarding your comments we reply that:

The sum of cations and anions of the nutrient solutions used in this study is equal. According to his suggestion, we change the units from percent to meq/L in table 1 of the manuscript. These meq/L of cations and anions were prepared with the fertilizer sources described in table 2. We consider that with this change the concentrations of the nutrient solutions used in this study have been clarified.

We add another reference that explains the biostimulant action mechanism of chitosan in the growth and yield of plants. We will continue working on this topic to verify the proposed hypothesis and try to explain the phenomenon.

Reviewer 5 Report

Thank you well revised.

Author Response

Thank you