G×E Analysis of Early Growth Traits of Populus deltoides in East China by Using BLUP-GGE

Round 1

Reviewer 1 Report

The manuscript found that the growth traits of 5-year-old Populus deltoides were mainly controlled by genetic factors, and the performance of its traits was significantly affected by genotype, environment, and G×E impact. BLUP-GGE technology was used to evaluate the experimental sites and screen for excellent genotypes. The test results showed that SX was the most suitable place for breeding and planting of P. deltoides in East China. Excellent genotypes with high yield were selected in 3 experimental sites, and excellent genotypes suitable for planting in East China were selected. This paper provides a theoretical and technical reference for the selection of poplar excellent genotypes, and provides a reference for the selection of poplar cultivars in East China and its similar climatic regions.

It was my pleasure to review the above-titled manuscript, in which the authors had carried out a large number of measurements and analyses. This study is now a concerned topic of research. I find it interesting, and important from both scientific, as well as practical point of view. However, there are still some minor problems in this manuscript. 

1.     Introduction: The trial sites are underrepresented in East China, and it is recommended to add evidence that the trial sites are representative.

2.     Line 65, It is wrong that “However, few studies on P. deltoides have been conducted in China”.

3.     Figure 1, 38 poplar seedlings misrepresentation.

4.     Line 110-111, Table 3, the abbreviations of the phenotypic variation coefficient and the genetic variation coefficient are not uniform, and the abbreviations are wrong.

5.     Line 111-124, Some letters are formatted incorrectly. ×αj is misrepresented. It is recommended to check the grammar and meaning.

6.     "** means extremely significant difference (P < 0.0001)." is generally P < 0.01. It is recommended to change P < 0.0001 to P < 0.01.

7.     Incorrect location of Figure 2 and Figure 1.

8.     3.3.2, Discuss the reasons for SX county as the most suitable place for cultivation and selection of P. deltoids.

9.     Figure 1 does not illustrate how the best ME genotypes are represented in each setting.

 

10.  Line 294-296, lack of evidence for the importance of other poplar traits.

Author Response

Point 1: Introduction: The trial sites are underrepresented in East China, and it is recommended to add evidence that the trial sites are representative.

Response 1: Shandong Province is a representative province of poplar production and intensive cultivation in China, and it is also the main planting area of P. deltoides in East China. In this study, three experimental sites in Shandong Province were selected as typical cultivation environmental conditions of P. deltoides in East China. I have elaborated in the original text(Lines 67-74).  

Point 2: Line 65, It is wrong that “However, few studies on P. deltoides have been conducted in China”.

Response 2: I have modified “However, few studies on P. deltoides have been conducted in China” statement. The new statement is revised to “However, up to date, there are only a few studies on early selection of Populus using BLUP-GGE in China”, and relevant evidence is provided(Lines 62-67).

Point 3: Figure 1, 38 poplar seedlings misrepresentation.

Response 3: I modified “38 poplar seedlings” to change “38 poplar seedlings” to “38 P. deltoides genotypes” (Lines 90(figuer 1)).

Point 4: Line 110-111, Table 3, the abbreviations of the phenotypic variation coefficient and the genetic variation coefficient are not uniform, and the abbreviations are wrong.

Response 4: I have changed the abbreviations for the phenotypic variation coefficient and the genetic variation coefficient in Table 3 to their full names and made the full text identical (Lines 151(table 3)).

Point 5: Line 111-124, Some letters are formatted incorrectly. ×αj is misrepresented. It is recommended to check the grammar and meaning.

Response 5: The formatting of all letters incorrectly bolded in this article has been modified. The meaning of ×αj has been changed from “block and block×genotype” to “block×genotype” (Lines 121, 128-129).

Point 6: "** means extremely significant difference (P < 0.0001)." is generally P < 0.01. It is recommended to change P < 0.0001 to P < 0.01.

Response 6: I have modified "** means extremely significant difference (P < 0.0001)."to "** means extremely significant difference (P < 0.01).", and the corresponding “P < 0.0001” in the article to “P < 0.01” (Lines 157,167(table4)).

Point 7: Incorrect location of Figure 2 and Figure 1.

Response 7: In 3.3.1, I modified the sequence of analyzing Figure 1 and Figure 2, so that Figure 1 in the article is analyzed first(Lines 179-190).

Point 8: 3.3.2, Discuss the reasons for SX county as the most suitable place for cultivation and selection of P. deltoids.

Response 8: SX was the most suitable one for planting and breeding of P. deltoides among the three experimental sites, which may be related to the similar environmental conditions between SX and place of origin of P. deltoides. In addition, SX is located in the alluvial plain of the Yellow River, with fertile soil and excellent drainage, suitable for the growth of P. deltoides. I added this part to the Discussion in the text (Lines 306-310).

Point 9: Figure 1 does not illustrate how the best ME genotypes are represented in each setting.

Response 9: In Figure 1, the vertices in the polygon furthest from the center are the best genotypes in each ME. I added a in Figure 1”The red line represents the demarcation line of the mega-environment, and the environmental conditions of the test sites between the two red lines are similar. The vertices in the polygon furthest from the center are the best genotypes in each mega-environment” (Lines 195-198).

Point 10: Line 294-296, lack of evidence for the importance of other poplar traits.

Response 10: I have re-characterized future research directions and added evidence for the importance of other traits in poplar. (Lines 315-317)

Author Response File: Author Response.docx

Reviewer 2 Report

 

In the manuscript, the authors used BLUP-GGE technology to explore the genetic characteristics and genotype-environment interaction of early growth traits of P. deltoides at three experimental sites in Shandong Province, and screened out the suitable experimental sites and excellent genotypes of P. deltoides in East China. In this study the authors had carried out a large number of measurements and analyses. The results of this study can provide a theoretical basis for the breeding and application of P. deltoides. 

 

However, it has to be said that there are still some problems at the time of writing the article. At the same time, the overall language of the article needs to be revised and improved.

 

1.     The three experimental sites in the article are all in Shandong Province, but the breeding results are in East China.The relationship between Shandong Province and East China in the paper needs to be clarified, and it is suggested to explain the representativeness of Shandong Province in East China.

 

2.     Line 73-77, detailing the indicators and methods used in the selection of the two seedling stages.

 

3. Table1, the authors use the term “seedlings” in manuscript which may not correct considering that they did not germinate any seeds during the experiments performed.

 

4.     Line 111, 115, 117, 122-123. The letter format in the formula is wrong.

 

5.     Line 117-119. “block and block×genotype” is mistake.

 

6.     The full name of the abbreviation needs to be marked in the tables. Supplement the meaning represented by different numbers of *.

 

7.     “P” in P value should be changed to “p”, and check the full text.

 

8.     3.2, 3.3 titles are not clear. It is recommended to refine the title and summarize the research content.

 

9.     The positions of Figure 2 and Figure 1 are interchanged, and the content in Figure 2 is the first to be analyzed in.

 

10.  Line 171-174, misrepresentation. It is recommended to check the grammar and meaning.

 

11.  Figure 1 and Figure 3 are not clearly annotated.

 

12.  Line 275-276, the climate description in Shandong Province may be inaccurate.

 

 

 

Author Response

Point 1: The three experimental sites in the article are all in Shandong Province, but the breeding results are in East China.The relationship between Shandong Province and East China in the paper needs to be clarified, and it is suggested to explain the representativeness of Shandong Province in East China.

Response 1: Shandong Province is a representative province of poplar production and intensive cultivation in China, and it is also the main planting area of P. deltoides in East China. In this study, three experimental sites in Shandong Province were selected as typical cultivation environmental conditions of P. deltoides in East China. I have elaborated in the original text(Lines 67-74).

Point 2: Line 73-77, detailing the indicators and methods used in the selection of the two seedling stages.

Response 2: In 2014, the seedling height and ground diameter of half-sib families of P. deltoides were comprehensively evaluated by character expression level method, and excellent individual plants were screened out. In 2015-2016, the seedling height and ground diameter of P. deltoides genotypes were comprehensively screened for 2 consecutive years by Bregkin multi-trait evaluation method. The specific indicators and methods for the selection of the two seedling stages have been described in the article (Lines 79-89).

Point 3: Table 1, the authors use the term “seedlings” in manuscript which may not correct considering that they did not germinate any seeds during the experiments performed.

Response 3: I modified “ seedlings” to change “ seedlings” to “genotypes” (Lines 90(figuer 1)).

Point 4: Line 111, 115, 117, 122-123. The letter format in the formula is wrong.

Response 4: I checked the formatting of all letters in this article and modified them. Mainly includes incorrectly bolded letters and letters that are italicized (Lines 118-123).

Point 5: Line 117-119. “block and block×genotype” is mistake.

Response 5: I changed “block and block×genotype” to “block×genotype” in the article (Lines 128-129).

Point 6: The full name of the abbreviation needs to be marked in the tables. Supplement the meaning represented by different numbers of *.

Response 6: I have indicated the full abbreviations of all forms in the article. The meanings represented by different numbers* have been indicated in the corresponding table or text (table3-5).

Point 7: “P” in P value should be changed to “p”, and check the full text.

Response 7: I have changed “P” to “p” in the full text (Lines 157, 167(table 4)).

Point 8: 3.2, 3.3 titles are not clear. It is recommended to refine the title and summarize the research content.

Response 8: I have modified the titles of 3.2 and 3.3 respectively, the title of 3.2 is “Mixed linear model test for tree height and DBH”, and the title of 3.3 is “BLUP-GGE analysis for tree height and DBH” (Lines 152,171).

Point 9: The positions of Figure 2 and Figure 1 are interchanged, and the content in Figure 2 is the first to be analyzed in.

Response 9: In 3.3.1, I modified the sequence of analyzing Figure 1 and Figure 2, so that Figure 1 in the article is analyzed first (Lines 179-190).

Point 10: Line 171-174, misrepresentation. It is recommended to check the grammar and meaning.

Response 10: I have re-described the content of this section and it is now located in the article as: Lines 182-186.

Point 11: Figure 1 and Figure 3 are not clearly annotated.

Response 11: I have re-described the annotations of Figure 1 and Figure 3. For details, see Lines 194-198 and 243-251.

Point 12: Line 275-276, the climate description in Shandong Province may be inaccurate.

Response 12: I have mainly revised the climate description for Rizhao City, Shandong Province. The three trial sites are re-described in the article as “The ecosystems of the three test sites in Shandong Province are highly distinct: the three test sites have a temperate monsoon climate, but the eastern hilly zone (site RZ) is near by the coast, and the southwest plain area (SX) and the south-central hilly region (BX) are located on land.” (Lines 293-298).

Reviewer 3 Report

I attach the comments because I wrote formulae thet can't be seen in this window

Comments for author File: Comments.pdf

Author Response

Point 1: Line 79 (table 1) and 84: Define acronym “CKs” (I could presume control or checking genotypes, but….)  

Response 1: "CKs" in the original article stands for the control genotypes, which has been modified to the “control genotypes”(Line 90 (table 1); Line 95,229).

Point 2: Lines 114-124: Why use bold fonts for random effects in models? Use latin and Greek letters properly for fixed and random effects instead of mixing the codification and don’t change the letter of the factor when it acts in the interaction, I suggest this harmonized codification for the two models:

???? = ? + ?? + ?? + ?? × ?? + ??

????? = ? + ?? + ?? + ?? + ?? × ?? + ??

Response 2: The use of bold fonts for random effects in original models was that I had formatted the font incorrectly, which has now been modified. I think the two models you suggested me with are more suitable and have been modified according to your suggestions, thank you very much for your guidance(Lines 123-135).

Point 3: Please explain the meaning of red lines in Fig 1

Response 3: The red line represents the demarcation line of the mega-environment, and the environmental conditions of the test sites between the two red lines are similar. I have added the meaning of the red line to Figure 1 in the article (Lines 193-198(Figure 1)).

Author Response File: Author Response.docx