A Fine Line between Phytotoxicity and Blue When Producing Hydrangea macrophylla in a Nursery at a Low Substrate pH

Round 1

Reviewer 1 Report

This article is an interesting piece of work that should be of interest to hydrangea growers. The results are presented in a very detailed and clear manner and are described in detail. However, the presented figures do not indicate the statistical significance of the results obtained.

While reading this article, one thought comes to my mind. Growers successfully grow and sell blue hydrangeas, and the plants are properly developed, bloom nicely, and their appearance is pleasing to customers who are so eager to buy them. Shouldn't the first step in the conducted research be collecting accurate information from breeders about the conditions in which they grow plants (if they are doing it successfully) and possibly checking how changes in these rules will affect the plants?

I cannot refer to supplementary materials as these files are not available for me.

Author Response

This article is an interesting piece of work that should be of interest to hydrangea growers. The results are presented in a very detailed and clear manner and are described in detail. However, the presented figures do not indicate the statistical significance of the results obtained.

We indicate in 2.3, the Statistics Analysis section of the Materials and Methods, that significance was determined at the 5% level and in each figure caption that error bars signify 1 standard deviation from the mean.

While reading this article, one thought comes to my mind. Growers successfully grow and sell blue hydrangeas, and the plants are properly developed, bloom nicely, and their appearance is pleasing to customers who are so eager to buy them. Shouldn't the first step in the conducted research be collecting accurate information from breeders about the conditions in which they grow plants (if they are doing it successfully) and possibly checking how changes in these rules will affect the plants?

Now line 86
While many blue hydrangeas are for sale in the retail marketplace, those marketable plants represent a fraction of the total crop grown.  Many producers struggle with bluing hydrangeas at a substantial cost due to plants that must be thrown away, are rejected by wholesale customers, or miss sales windows and must remain in production longer in order to achieve the desired flower color.  Growers also offer discounts on crops that are not blue, reducing their projected income. We know this because hydrangea producers routinely contact us because of our positions at universities and the U.S. Department of Agriculture and ask for help with controlling flower color. What works at one nursery often doesn’t work at another – even for a nursery that produces H. macrophylla in multiple regions, multiple production protocols are necessary and repeatedly achieving success is still a challenge. Within the same nursery, what works one year may not work in another.  We added a few passages that describe this problem and more clearly establish the need for this research. 

I cannot refer to supplementary materials as these files are not available for me.

The supplemental figures are in the MDPI submission portal.  We apologize for the inconvenience.

Author Response File: Author Response.docx

Reviewer 2 Report

The present work is interesting and has the potential for publication.

But before proceeding with a more detailed assessment, I was left with severe doubts about how the statistical analysis was carried out.

I request that a table be created with the pvalues, as this will make it easier to perform an analysis.

I also suggest that the figures are better presented, as it is confusing for the reader.

After this request is made, I will do a second round of evaluation.

Author Response

The present work is interesting and has the potential for publication.

But before proceeding with a more detailed assessment, I was left with severe doubts about how the statistical analysis was carried out.

I request that a table be created with the pvalues, as this will make it easier to perform an analysis.

Now line 352 and 278
We added p-values to table 2. All other tables, including the supplemental table, already had p values. Please also see the description of our statistical analysis, section 2.3.

I also suggest that the figures are better presented, as it is confusing for the reader.

We are not sure what is confusing about the figures as they are in a common format. We are not sure how to address this comment.  If the reviewer has specific recommendations for editing the figures we will be happy to make those changes to the best of our ability.

After this request is made, I will do a second round of evaluation.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Dear editor,

After the requested requests, the authors performed to their satisfaction.

So my suggestion is to approve the article.