Genetic Variation and the Relationships Among Growth, Morphological, and Physiological Traits in Pterocarpus macrocarpus: Implications for Early Selection and Conservation
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors- Most of the tables are not inserted into the right place in the text. The quality of the manuscript would be improved if tables were inserted into the main text close to their first citation. My suggestion is first to mention the table in the text, then the concrete table, and then the description of the results presented in this table.
- It would be better if, in the “2.2.2. Physiological traits" subsection short description were added for each of the physiological parameters used (photosynthetic rate, transpiration rate and water use efficiency). The method used for photosynthetic rate includes measuring CO2 uptake using an infrared gas analyser. Which method was used for this measurement (reference)? Which method was used for measuring the transpiration rate (reference)?
- The conclusion section is too long. It would be better if it were more brief. Some parts of this section could be inserted at the end of the section Discussion.
Author Response
Reviewer 1
We thank the reviewer for the constructive feedback. We agree with all the comments and suggestions and have made all necessary changes accordingly. The following are the specifics:
Comment 1: Most of the tables are not inserted into the right place in the text. The quality of the manuscript would be improved if tables were inserted into the main text close to their first citation. My suggestion is first to mention the table in the text, then the concrete table, and then the description of the results presented in this table.
Response 1: Yes, we fully agree. All our tables are now embedded in the main text near their first citation as suggested. Please see Table 1-P8, Table 2-P15, Table 3-P16, Table 4-P17, Table 5-P18, Tables 6 to 8-P19, Table 9-P20, Table 10-P21, Tables 11-P21-22, Tables 12-P22-23, Table 13-P23, Tables 14-P23-24, Table 15-P24, Table 16-P25, Table 17-P26-27, and Table 18-P29-30.
Please note that we have deleted Tables 2-4 in response to the suggestion of another reviewer.
Comment 2: It would be better if, in the “2.2.2. Physiological traits" subsection short description were added for each of the physiological parameters used (photosynthetic rate, transpiration rate and water use efficiency). The method used for photosynthetic rate includes measuring CO2 uptake using an infrared gas analyser. Which method was used for this measurement (reference)? Which method was used for measuring the transpiration rate (reference)?
Response 2: Yes, we fully agree. We have now included the appropriate references [30] and [31].
- Leaf area was measured using a portable laser area meter (CI-202, CID Bio-Science) [30]
- The net photosynthetic rate (A; µmol CO₂ m⁻² s⁻¹) and transpiration rate (E; mmol H₂O m⁻² s⁻¹) were recorded over 30-second intervals following a 90-second chamber equilibration [31].
Comment 3: The conclusion section is too long. It would be better if it were more brief. Some parts of this section could be inserted at the end of the section Discussion.
Response 3: Yes, we fully agree. We have condensed our discussions and conclusions without losing the information we want to convey.
Reviewer 1
We thank the reviewer for the constructive feedback. We agree with all the comments and suggestions and have made all necessary changes accordingly. The following are the specifics:
Comment 1: Most of the tables are not inserted into the right place in the text. The quality of the manuscript would be improved if tables were inserted into the main text close to their first citation. My suggestion is first to mention the table in the text, then the concrete table, and then the description of the results presented in this table.
Response 1: Yes, we fully agree. All our tables are now embedded in the main text near their first citation as suggested. Please see Table 1-P8, Table 2-P15, Table 3-P16, Table 4-P17, Table 5-P18, Tables 6 to 8-P19, Table 9-P20, Table 10-P21, Tables 11-P21-22, Tables 12-P22-23, Table 13-P23, Tables 14-P23-24, Table 15-P24, Table 16-P25, Table 17-P26-27, and Table 18-P29-30.
Please note that we have deleted Tables 2-4 in response to the suggestion of another reviewer.
Comment 2: It would be better if, in the “2.2.2. Physiological traits" subsection short description were added for each of the physiological parameters used (photosynthetic rate, transpiration rate and water use efficiency). The method used for photosynthetic rate includes measuring CO2 uptake using an infrared gas analyser. Which method was used for this measurement (reference)? Which method was used for measuring the transpiration rate (reference)?
Response 2: Yes, we fully agree. We have now included the appropriate references [30] and [31].
- Leaf area was measured using a portable laser area meter (CI-202, CID Bio-Science) [30]
- The net photosynthetic rate (A; µmol CO₂ m⁻² s⁻¹) and transpiration rate (E; mmol H₂O m⁻² s⁻¹) were recorded over 30-second intervals following a 90-second chamber equilibration [31].
Comment 3: The conclusion section is too long. It would be better if it were more brief. Some parts of this section could be inserted at the end of the section Discussion.
Response 3: Yes, we fully agree. We have condensed our discussions and conclusions without losing the information we want to convey.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThis manuscript seems to be the final (?) submission from the first author's MSc thesis from 1987. This does not invalidate the paper, but it does explain why the mss. is sooo long, and why it has so many citations from 20-30-40 years ago, and relatively few from the past 5 years. The authors decided to update the bibliography, but not to take out anything written in what seems to have been a previous (thesis?) version from long ago. This also explains the long-windedness of this 57-page mss,, as the thesis version was likely very detailed.
The authors conclusions regarding use of WUE as a selection tool in breeding hardwoods are fine. The length of the path to those conclusions is very long, though. Many of the tables present correlations that are NS. Those tables could easily be shortened by stressing only the significant correlations. Table 1 has rainfall regions of 1000-1200mm listed as 'moist', while regions with 1300-1600 mm rainfall are listed as 'dry'. This is probably a mistake. Tables 2-4 are not needed, and Table 5 can be summarized in two sentences. Tables 6-7 would be simpler as line graphs, and table 8 could be bar graphs. That height and diameter correlate is not surprising, but it is nice to see that demonstrated over 6 populations from different regions and climate. The overall r values can be mentioned in a sentence or two, without repetitious tables. Similar editing can be done for the many other tables in the manuscript.
***The manuscript does not follow the Rule of the Decimal Place. If there are 3 or more digits to the left of the decimal, then no digits should be to the right of the decimal. Two digits to the left of the decimal allows only one digit to the right of the decimal. One or no digits to the left allows two digits to the right. If there is a need for more than two digits to the right of the decimal to make matters clear, then in most cases the number should be multiplied by at least 100 for clarity of presentation.
The conclusions are fine, but the suggestions for further work can be condensed or omitted. Perhaps some recent studies on other tropical hardwoods can be cited...
Author Response
Reviewer 2
We thank the reviewer for the constructive feedback. We agree with all the comments and suggestions and have made all necessary changes accordingly. The following are the specifics:
Comment 1: This manuscript seems to be the final (?) submission from the first author's MSc thesis from 1987. This does not invalidate the paper, but it does explain why the mss. is sooo long, and why it has so many citations from 20-30-40 years ago, and relatively few from the past 5 years. The authors decided to update the bibliography, but not to take out anything written in what seems to have been a previous (thesis?) version from long ago. This also explains the long-windedness of this 57-page mss,, as the thesis version was likely very detailed
Response 1: No, this manuscript is not from Dr. Chaiyasit’s MSc thesis. This research forms part of Dr. Chaiyasit’s doctoral thesis at the University of Alberta, titled 'Genetic variation studies in Pterocarpus macrocarpus Kurz as revealed by isozymes, morphological, and physiological traits.' The isozyme research resulted in two publications, one in Forest Ecology and Management and the other in the Journal of Heredity. After Dr. Chaiyasit returned to Thailand, he faced both personal and work-related challenges. As a result, he was unable to complete his writing on the morphological and physiological traits.
Over the past 12 months, Francis Yeh has received numerous invitations from journals to submit papers (articles or reviews) and to serve as a guest editor on topics related to forest genetics, tree improvement, and conservation. It is worth noting that over the past 20 years, nearly 90% of forestry studies at academic institutions have focused on molecular genetics. Labour-intensive research, such as Dr. Chaiyasit's study on morphological and physiological traits, is rare. However, morphological and physiological traits form the basis of tree improvement and conservation. Therefore, I invited Dr. Chaiyasit to collaborate with me on writing about these traits for submission to MDPI-Conservation.
Our manuscript is lengthy because the research focused on studying many important traits. Note that Dr. Chaiyasit’s thesis chapter is 63 pages long, with single-line spacing for references. When we decided to submit to the MDPI journal Conservation, we revised and updated all relevant references, added a title page and abstract, and rewrote and edited the Introduction, Results, Discussion, and Conclusion sections. The Materials and Methods and the data in the tables were not changed much. References are an important part of a manuscript. In our case, we edited the original references and added 53 new references. Our revised manuscript is now 50 pages in total.
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Comment 2. The authors conclusions regarding use of WUE as a selection tool in breeding hardwoods are fine. The length of the path to those conclusions is very long, though. Many of the tables present correlations that are NS. Those tables could easily be shortened by stressing only the significant correlations. Table 1 has rainfall regions of 1000-1200mm listed as 'moist', while regions with 1300-1600 mm rainfall are listed as 'dry'. This is probably a mistake. Tables 2-4 are not needed, and Table 5 can be summarized in two sentences. Tables 6-7 would be simpler as line graphs, and table 8 could be bar graphs. That height and diameter correlate is not surprising, but it is nice to see that demonstrated over 6 populations from different regions and climate. The overall r values can be mentioned in a sentence or two, without repetitious tables. Similar editing can be done for the many other tables in the manuscript.
Response 2:
(a). Table 1 is accurate. The climate data in Thailand are mainly collected from meteorological stations in urban areas rather than forest regions. As a result, rainfall data are not used to classify forest types. In Thailand, forest types are generally classified based on topography and species composition. MDF includes both evergreen and deciduous tree species, while DDF mainly consists of deciduous trees. In MDF, only deciduous trees shed their leaves during the dry season, whereas evergreen trees keep their foliage year-round. In DDF, nearly all trees lose their leaves during the dry season. Therefore, MDF has a greater capacity to retain moisture than DDF. Whether a site is moist or dry ultimately depends on the type of forest. We have now added this description to the manuscript (P8, L164-171) to prevent any misunderstandings.
(b). As per your suggestion, we have now removed Tables 2-4. However, Table 2 contained details on the biomass of assessed plant parts. Therefore, we must include these details in the text (P10-L219-222).
(c). Table 5 is now Table 2 in our revised manuscript. Here, we show the average seedling survival, the variation in survival at the family level, and a statistical test of survival across populations. These results suggest that consistent nursery conditions and excellent management had a stronger influence than genetic variation on early survival outcomes. We believe that summarising everything in two sentences is insufficient to fully express our points. Therefore, we choose to keep this table.
(d) The target audiences of our paper are individuals interested in forest genetics, tree improvement, and gene conservation. They prefer to see precise values such as means, standard errors, p-values, and detailed statistical results in tables. For this reason, we favour tables over graphs in this manuscript. Please note that in another manuscript we are currently preparing, we use five sets of graphs to illustrate the patterns of photosynthesis, transpiration, water-use efficiency, and xylem water potential in seedlings under well-watered and water-stressed conditions. Therefore, our choice between using tables or graphs depends on the nature of the data, the message we aim to convey, and the expectations of our target audiences.
Comment 3: The manuscript does not follow the Rule of the Decimal Place. If there are 3 or more digits to the left of the decimal, then no digits should be to the right of the decimal. Two digits to the left of the decimal allows only one digit to the right of the decimal. One or no digits to the left allows two digits to the right. If there is a need for more than two digits to the right of the decimal to make matters clear, then in most cases the number should be multiplied by at least 100 for clarity of presentation.
Response 3: Thank you for bringing this to our attention. We have now applied the Rule of the Decimal Place.
Comment 4: The conclusions are fine, but the suggestions for further work can be condensed or omitted. Perhaps some recent studies on other tropical hardwoods can be cited...
Response 4: Yes, we completely agree. We have condensed our discussions and conclusions without losing the information we want to convey.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsDear authors,
Congratulations on your research and the thorough presentation of your data. However, I recommend a few modifications that could enhance the clarity and overall impact of the manuscript.
In the Materials and Methods section, it would be preferable to represent the geographical location of the study graphically rather than in a table. A visual representation would help readers quickly grasp the spatial context.
The results are conclusive and well-supported, but I suggest including an appropriate graphical representation to help condense the information and improve accessibility for readers.
Thank you
Author Response
Dear authors,
Congratulations on your research and the thorough presentation of your data. However, I recommend a few modifications that could enhance the clarity and overall impact of the manuscript.
Dear Reviewer, thank you for your kind compliments. We appreciate your constructive feedback. The following are the specifics:
Comment 1: In the Materials and Methods section, it would be preferable to represent the geographical location of the study graphically rather than in a table. A visual representation would help readers quickly grasp the spatial context.
Response 1: Yes, we fully agree. We have now added the figure below to the manuscript.
Figure 1. Map of Thailand showing the locations (●) of six populations of P. macrocarpus included in this study
Comment 2: The results are conclusive and well-supported, but I suggest including an appropriate graphical representation to help condense the information and improve accessibility for readers.
Response 2: The target audiences of our paper are individuals interested in forest genetics, tree improvement, and gene conservation. They prefer to see precise values such as means, standard errors, p-values, and detailed statistical results in tables. For this reason, we favour tables over graphs in this manuscript.
Please note that in another manuscript we are currently preparing, we use five sets of graphs to illustrate the patterns of photosynthesis, transpiration, water-use efficiency, and xylem water potential in seedlings under well-watered and water-stressed conditions. Therefore, our choice between using tables or graphs depends on the nature of the data, the message we aim to convey, and the expectations of our target audiences.
Dear authors,
Congratulations on your research and the thorough presentation of your data. However, I recommend a few modifications that could enhance the clarity and overall impact of the manuscript.
Dear Reviewer, thank you for your kind compliments. We appreciate your constructive feedback. The following are the specifics:
Comment 1: In the Materials and Methods section, it would be preferable to represent the geographical location of the study graphically rather than in a table. A visual representation would help readers quickly grasp the spatial context.
Response 1: Yes, we fully agree. We have now added the figure below to the manuscript.
Figure 1. Map of Thailand showing the locations (●) of six populations of P. macrocarpus included in this study
Comment 2: The results are conclusive and well-supported, but I suggest including an appropriate graphical representation to help condense the information and improve accessibility for readers.
Response 2: The target audiences of our paper are individuals interested in forest genetics, tree improvement, and gene conservation. They prefer to see precise values such as means, standard errors, p-values, and detailed statistical results in tables. For this reason, we favour tables over graphs in this manuscript.
Please note that in another manuscript we are currently preparing, we use five sets of graphs to illustrate the patterns of photosynthesis, transpiration, water-use efficiency, and xylem water potential in seedlings under well-watered and water-stressed conditions. Therefore, our choice between using tables or graphs depends on the nature of the data, the message we aim to convey, and the expectations of our target audiences.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript is shortened, but not enough. Review articles can have 100 or more cited references; research reports should be limited to 50-60 references. Some tables have been dropped, but the authors still insist on providing the data range, as well as mean, std dev and grand mean. These data would be much more easily digested as graphs, no matter what the second author claims. In most cases, there is no statistically significant difference between data points on the population level, and we are not given (and, frankly, do not need) data on the the family level where there apparently are some differences. Tables 3, 4, and 5 (where abbreviations should be defined in any case) should be graphs.
Other points:
line 31 and elsewhere showed, displayed, exhibited-- all these are unnecessary words for a sentence that can begin "There were...".
The word "traits" appears 22 times. Less is more, in this case...
130 Burma is called Myanmar these days, but I guess the map is from the 30+ year-old thesis.
169-70 DDF If trees lose leaves, they transpire less. Why then is their soil dryer than MDF environments?
189 What was the height, +/- 10%?
198 Osmocote is a slow-release fertilizer. It is usually supplied in versions that are good for at least 3 months, and usually for 6 months. Why was it applied twice in less than 3 months?
200 location of Onset Computer Corporation?
308 notable compared to what?
329 "showed greater variablity"--> varied more. lots of over-writing in this mss. Try ChatGPT or a live editor to shorten things.
335 "Height growth" why not just height? perhaps "height extension"?? as height changes over seasons, most people intuit that "height" over time = growth.
Table 11 and elsewhere. Only two digits are needed after the decimal.
I recommend 'moderate revision', although the option is not available. That's why 'major revision' is noted.
Author Response
Round 2, Reviewer 1
We thank the reviewer for all the constructive feedback. We agree with all the comments and suggestions and have made all necessary changes accordingly. The following are our replies:
Comment 1: The manuscript is shortened, but not enough. Review articles can have 100 or more cited references; research reports should be limited to 50-60 references. Some tables have been dropped, but the authors still insist on providing the data range, as well as mean, std dev and grand mean. These data would be much more easily digested as graphs, no matter what the second author claims. In most cases, there is no statistically significant difference between data points on the population level, and we are not given (and, frankly, do not need) data on the family level where there apparently are some differences. Tables 3, 4, and 5 (where abbreviations should be defined in any case) should be graphs.
Response 1: Please note that we have numerous references because we need to discuss growth, biomass, and physiology. We have now reduced the number of references from 112 to 96. Following your suggestion, we now have Figure 2 to represent Tables 3 and 4, and Figure 3 to represent Table 5. Additionally, the heritability estimates for height and diameter, as shown in Table 9 (former), are illustrated in Figure 4, while those for biomass and physiological traits are displayed in Figure 5. The genetic correlations between seed weight and all other traits (former Table 18) are displayed in Figure 6.
Comment 2: Other points:
C2.1 line 31 and elsewhere showed, displayed, exhibited-- all these are unnecessary words for a sentence that can begin "There were...".
R2.1 Noted; made changes whenever possible.
C2.2 The word "traits" appears 22 times. Less is more, in this case...
R2.2 There is now less because we have removed the word “trait” whenever possible.
C2.3 130 Burma is called Myanmar these days, but I guess the map is from the 30+ year-old thesis.
R2.3 Yes, Figure 1 now displays Myanmar instead of Burma.
C2.4 DDF If trees lose leaves, they transpire less. Why then is their soil dryer than MDF environments?
R2.4 DDF generally features shallow, sandy, and rocky soil. The tree species in DDF are deciduous, shedding leaves during drought periods. This is a natural process. DDFs are typically found in northeastern Thailand, an area considered a dry zone of the country. It is mainly a high plateau with sandy soil, so DDFs are usually located on dry sites. MDF has deeper soil and retains moisture longer. It contains both deciduous and evergreen species. During the dry season, deciduous species shed their leaves, while evergreen ones keep theirs and continue to grow, albeit more slowly. This indicates that there is enough moisture for trees to keep their leaves turgid and perform gas exchange (photosynthesis and transpiration). The presence of evergreen species suggests enough moisture for these trees to survive until rain falls. The drought usually lasts about two months. Deciduous species may be more sensitive to drought and shed their leaves earlier, likely as a specific trait of the species. In Thailand, which has a tropical monsoon climate, rain typically originates from the Gulf of Thailand and the Andaman Sea. This rain moves towards the north and northeast. Besides these sources, the northeast region also receives rainfall from numerous storms that occur in the South China Sea each year. These storms pass through Vietnam, Laos, and towards the northeast part of the country before dissipating or moving into the central and northern regions. As a result, the annual rainfall in the northeast is high; however, most of the water is lost through runoff, and there is less water retention due to the sandy soil structure. This may explain why the DDF in this study (Table 1), which are in the northeast, have higher annual rainfall than MDF but are still considered dry sites. Therefore, in this context, whether a site is moist or dry makes no difference to transpiration. It is more likely related to the structure of the forests rather than physiological factors.
C2.5 What was the height, +/- 10%?
R2.5 Sorry, it should read: “After 12 weeks, 16 healthy seedlings per family (totaling 1,792) were randomly selected and transplanted into 3-L terracotta pots (17.8 cm diameter × 20.3 cm depth) filled with the same substrate mixture, arranged in a randomized complete block design (RCBD) with 16 replicates (single-tree plots).” (L190-193).
C2.6 Osmocote is a slow-release fertilizer. It is usually supplied in versions that are good for at least 3 months, and usually for 6 months. Why was it applied twice in less than 3 months?
R2.6 The Osmocote used in our greenhouse study was a 2-3 month formulation. It was not intended for periods longer than 3 or 6 months. We have detailed this in our revised manuscript at L189-190 and L198-199.
C2.7 location of Onset Computer Corporation?
R2.7 Yes, we have added “Bourne, MA, USA” to indicate the location of Onset Computer Corporation. (L201).
C2.8 notable compared to what?
R2.8 It is just an adjective, we can delete it “high across all populations” (L309-310).
C2.9 "showed greater variablity"--> varied more. lots of over-writing in this mss. Try ChatGPT or a live editor to shorten things.
R2.9 We changed to “survival rates ranged from 75% to 100%” (L330).
C2.10 "Height growth" why not just height? perhaps "height extension"?? as height changes over seasons, most people intuit that "height" over time = growth.
R2.10 Agree. We have removed the word “growth” from “height growth” and now refer to it as heights because we have 10 measurements from H3 to H30. The same applies to diameter.
C2.11 Table 11 and elsewhere. Only two digits are needed after the decimal.
R2.11 Yes, we updated all tables to show two digits.
C2.12 I recommend 'moderate revision', although the option is not available. That's why 'major revision' is noted.
R2.12 Thank you.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsDear authors,
Dear authors,
Congratulations on your paper, and thank you for making the requested revisions.
Author Response
Dear Reviewer,
We thank you for your constructive feedback.
We are pleased to tell you that we are using graphs to display some of our results. Figure 2 represents Tables 3 and 4, and Figure 3 represents Table 5. Additionally, the heritability estimates for height and diameter, as shown in Table 9 (former), are illustrated in Figure 4, while those for biomass and physiological traits are displayed in Figure 5. The genetic correlations between seed weight and all other traits (former Table 18) are displayed in Figure 6.
Round 3
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript is improved. There are still too many citations, and the tables can probably be condensed (for example, printing only three values for H or D-- early, mid, and late measurement), but overall the material is worthy of publication.
Author Response
Dear Reviewer: We thank you for your constructive comments. The following are our responses:
Comment 1. The manuscript is improved. There are still too many citations.
Response 1. Yes, we have now reduced the number of citations from 96 to 77.
Comment 2. The tables can probably be condensed (for example, printing only three values for H or D-- early, mid, and late measurement).
Response 2. Tables for consideration are 8, 9 and 13. The condensing will reduce the size of these tables. However, after careful consideration, we want to keep them because all our figures, etc, are already based on the full complement of measurements.
Comment 3. Overall, the material is worthy of publication.
Response 3. We agree and thank you for spending the time to help us improve our manuscript.
