Genomic Selection for Growth and Wood Traits in Castanopsis hystrix
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear Authors,
hereby I am providing you with my comments and suggestions on the paper under the title "Genomic selection for growth and wood traits in Castanopsis hystrix". The topic of the paper is of a great interest from both the forest breeding and wood evaluation point of view. The title is clear and written in good form. The abstract is clear and provides the necessary information on the study conducted in detail. The keywords provided and all essential. The introduction is well constructed in content, while it provides all the necessary information on the topic presented, especially giving the significance on the selection of the wood species. The objective and specific objectives of the paper are clearly defined. The materials and methodology section is clearly described with a proper methodology used. Certain suggestions are provided for the results section:
- Figure 1. - the graphical presentation of the descriptive statistics is a bit confusive. Is it possible to present these results in the form of table?
Discussion: isn't there any more references for wood species to be compared with?
Conclusions: is it possible to more precisely comment on the continuation of this resarch/or on the applicability of this/different methods in the future? What methodology would be applicable to other or more wood species?
Author Response
Comments 1： - Figure 1. - the graphical presentation of the descriptive statistics is a bit confusive. Is it possible to present these results in the form of table?
Response 1： Figure 1. is mainly used to show the distribution and variation conditions of growth and wood traits, as well as their correlation relationship. We revised the figure notes to make it clear.
Comments 2：Discussion: isn't there any more references for wood species to be compared with?
Response 2：We added some relative references for wood species in the discussion.
Comments 3：Conclusions: is it possible to more precisely comment on the continuation of this resarch/or on the applicability of this/different methods in the future? What methodology would be applicable to other or more wood species?
Response 3：We added some comments on the continuation of this research. However, for the other or more wood species, based on our research and the other presented researches, we suggest that all the GS methods should be re-evaluated, that is, it is impossible to perform one GS model for all wood species, even the same tree species with different reference populations or different experiment sites.
Reviewer 2 Report
Comments and Suggestions for AuthorsSeveral questions and remarks regarding the paper by Zhang et al. “Genomic selection for growth and wood traits in Castanopsis hystrix”.
Various timber properties served as the work's primary criteria. Nevertheless, it is not evident what characteristics define precious timber. Which is preferable: less dense wood that is lighter, or more dense wood that is heavier? Which type of fibre (long or short, broad or narrow) is preferable? Please provide criteria for purchasing precious timber.
“The gene bank material was collected in 2001 from six provinces in southern China…” (Lines 85-86). Six provinces? Specifically, which provinces are considered? What is the distance between populations? In addition, could you please include a map?
“At the end of 2018, 226 clones of the reference population were measured for tree height (H) and diameter at breast height (DBH)…” (Lines 94-95) Please include age data for the sampled trees. Provide data on average size (height and diameter) of sampled trees.
“… and planted in the Yangjiang Forest Farm, Yunyong Forest Farm and Yunfu Forest Farm in Guangdong Province in April 2021...” (Lines 89-90). Why did the tree samples be planted in three distinct forest farms? Is it feasible that all of the variations in the findings you have found are more likely due to the way trees have adapted locally to varying microenvironments than to parental genetic regulation?
“…and the coefficient of variation of FW was lowest (10.10%)...” (Line 186) FW? What is this parameter? Decipher the abbreviation. Maybe "wood density" (WD) was intended as the parameter?
Add research limitations to the Discussion section.
Author Response
Comments 1： - Various timber properties served as the work's primary criteria. Nevertheless, it is not evident what characteristics define precious timber. Which is preferable: less dense wood that is lighter, or more dense wood that is heavier? Which type of fibre (long or short, broad or narrow) is preferable? Please provide criteria for purchasing precious timber.
Response 1： Agree. We added the criteria for better precious timber. The timber with longer fiber and higer iber length-width ratio has better mechanical properties, so we choose higher WD, longer FL, and higher LWR as the criteria of preferable precious timber.
Comments 2： - “The gene bank material was collected in 2001 from six provinces in southern China…” (Lines 85-86). Six provinces? Specifically, which provinces are considered? What is the distance between populations? In addition, could you please include a map?
Response 2： Since we have published one paper that has shown the details (also with a detailed map) of the gene bank material. Therefore, we added one sentence for its presentation.
Comments 3“At the end of 2018, 226 clones of the reference population were measured for tree height (H) and diameter at breast height (DBH)…” (Lines 94-95) Please include age data for the sampled trees. Provide data on average size (height and diameter) of sampled trees.
Response 3： We have included the age data for the sample trees. Each clone measured three sample trees.
Comments 4： - “… and planted in the Yangjiang Forest Farm, Yunyong Forest Farm and Yunfu Forest Farm in Guangdong Province in April 2021...” (Lines 89-90). Why did the tree samples be planted in three distinct forest farms? Is it feasible that all of the variations in the findings you have found are more likely due to the way trees have adapted locally to varying microenvironments than to parental genetic regulation?
Response 4： Actually, GS is just a prediction method of selection, which needs more field tests. Moreover, genotype by environment (GxE) is also known to have effects on GS prediction. Therefore, we planted the candidate population at three distinct forest farms, in order to carry out more studies of the candidate individuals and GxE effects in the future.
Comments 5： - “…and the coefficient of variation of FW was lowest (10.10%)...” (Line 186) FW? What is this parameter? Decipher the abbreviation. Maybe "wood density" (WD) was intended as the parameter?
Response 5： FW is a spelling mistake; it is FL. We have corrected it.
Comments 6： - Add research limitations to the Discussion section.
Response 6： We have included the limitations in the discussion.
Reviewer 3 Report
Comments and Suggestions for AuthorsModern breeding strategies rely on genomic selection (GS), an up-and-coming method for rapidly improving genetic gain per unit of time, especially in the case of multi-traits with low general heritability. The paper deals with GS and predicts a genomic estimate of breeding value (GEBV) to select favorable individuals for 5 selected growth traits (height, DBH, wood density, fiber length, and fiber width) among the several lines in Castanopsis hystrix Miq. Many factors, like marker density, size and composition of the studied population, number of QTL, and heritability can affect GS accuracies.
Such an approach is very appreciated in forest tree breeding, and the GS-based prediction for the progeny genetic value can overpass the naturally long-lasting reproductive cycle in forest tree species to select favorable individuals based on the predicted GEBV.
The prediction models used for the study seem adequate, even if based on 479 offspring young trees from 6 different provenances. The Authors rightly note in the Conclusions that the number of reference samples should be enlarged (minimum 2000 trees) for future more advanced GS prediction.
The article is quite original and has a high general interest in silviculture.
About the content:
The title, abstract, and keywords rightly reflect the paper's content. The conclusions are concise and based on the obtained results. In Discussion, there are some comments about GS prediction for height and DBH traits. What about other studied traits (i.e. fiber length and fiber width), Are there any similar results published?
Only a few improvements in the manuscript layout can be made:
L 10: while first time cited, give the full Latin name of the tree species
L 39: please refer to some author(s) of the GS theory claiming that 'at least one SNP is in direct linkage with one quantitative trait’
L 108: give the details about the method used for the DNA extraction from C. hystrix leaves (company, country)
L 214: add in the description “heritability” (H2) …. The reader should understand the picture without referring to the text. The same remark for all graphs in the manuscript
L 228: It is good manner to put an explication for all parameter abbreviations used on the graphs, for instance, H, DBH, etc.
Author Response
Comments 1： In Discussion, there are some comments about GS prediction for height and DBH traits. What about other studied traits (i.e. fiber length and fiber width), Are there any similar results published?
Response 1：Actually, there are not available studies on fiber traits in forest trees at present.
Comments 2：L 10: while first time cited, give the full Latin name of the tree species
Response 2：We have supplied all the full Latin name of the tree species.
Comments 3：L 39: please refer to some author(s) of the GS theory claiming that 'at least one SNP is in direct linkage with one quantitative trait’
Response 3：We have added the authors.
Comments 4：L 108: give the details about the method used for the DNA extraction from C. hystrix leaves (company, country)
Response 4：We have included the details of DNA extraction methods.
Comments 5：L 214: add in the description “heritability” (H2) …. The reader should understand the picture without referring to the text. The same remark for all graphs in the manuscript
Response 5：We have added the description and also the relative notes.
Comments 6：L 228: It is good manner to put an explication for all parameter abbreviations used on the graphs, for instance, H, DBH, etc.
Response 6：We have added the explication for all parameter abbreviations in all the figures.
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors answered all the questions and comments. The manuscript has been carefully revised.
