Genetic Control of Pitch Canker Response in Southern Pine and Southern Pine Hybrids
, Dominic Kain 5 and Jeremy T. Brawner 6Round 1
Reviewer 1 Report
The manuscript entitled „Genetic control of pitch canker response in southern pine and southern pine hybrids“ describes genetic control of pine pitch canker disease tolerance in southern pine and southern pine hybrids. Study of pine resistance to Fusarium circinatum is very important for forestry as there are no ameliorative techniques available for the disease.
Introduction in the manuscript is well written and contains information necessary for justification of undertaken study. The material and methods used are described in detail. The obtained results are clearly presented. Discussion is well written.
The only remark concerns the spelling of species names: they should be written in italics (lines 161, 176)
Author Response
The manuscript entitled “Genetic control of pitch canker response in southern pine and southern pine hybrids” describes genetic control of pine pitch canker disease tolerance in southern pine and southern pine hybrids. Study of pine resistance to Fusarium circinatum is very important for forestry as there are no ameliorative techniques available for the disease.
Introduction in the manuscript is well written and contains information necessary for justification of undertaken study. The material and methods used are described in detail. The obtained results are clearly presented. Discussion is well written.
Point 1: The only remark concerns the spelling of species names: they should be written in italics (lines 161, 176)
Response 1: We now spell out all species names in italics and replaced slash x caribaea with slash x P. caribaea. Slash pine and loblolly pine were left as common names in most instances, but correct nomenclature was checked throughout.
Reviewer 2 Report
It is of practical significance to use genetic parameter estimation method to try to clarify the resistance of different pine taxa（slash, loblolly and hybrid pine） to pine pitch canker(PPC). But, the followings should be revised:
1) Line 206：the equation(3) of the genetics gain was not used in the research, because there are no correlated contents in the Results, Disscusion and Conclusions.
2) The data were mainly from seedling stage, so it is suggested to combine more actual survey results of forest land to reveal the actual situation more truly.
3) The biological Latin name writing format is not standard.
Author Response
It is of practical significance to use genetic parameter estimation method to try to clarify the resistance of different pine taxa slash, loblolly and hybrid pine) to pine pitch canker (PPC). But, the followings should be revised:
Point 1: Line 206：the equation (3) of the genetics gain was not used in the research, because there are no correlated contents in the Results, Discussion and Conclusions.
Response 1: We removed the genetic gain equation as suggested because we do not show results.
Point 2: The data were mainly from seedling stage, so it is suggested to combine more actual survey results of forest land to reveal the actual situation more truly.
Response 2: This is a good suggestion, but unfortunately this is currently a gap in the literature. In future work, we plan to collaborate with partners to formally assay the extent of PPC infection in the US Southeast and describe it in historical context.
Point 3: The biological Latin name writing format is not standard.
Response 3: This has been corrected, along with a few other errors in grammar and formatting.
Reviewer 3 Report
Pitch canker is a very serious disease of pine and although some parts of the world remain free of the pathogen, there remains an urgent need to identify and employ resistant lines of the main plantation pine species and hybrids globally. This paper makes a useful contribution to this field and sets the scene for future breeding strategies. Minor improvements are suggested.
Add a new sub-heading between 2.1 and 2.2 for the pathogen. Include here the following: source, isolate age, whether they had been passaged recently through a host and reisolated before use, criteria for isolate selection, known pathogenicity, and related information. Whilst some of this information may be contained in previous studies, it better informs this study to have a reasonable amount of information in parallel with host data in 2.1.
Consider adding a figure so the experimental design & layout is easy for the reader to follow.
Was a standard potting mix used as in previous studies?
Were the seedlings fertilized?
Line 143 – The RSC protocol may not be known to all readers so consider adding a brief description of the height that the stems were cut (they were wounded, or were the tops severed?)
Line 144 – how much inoculum did each stem receive?
The information content in Section 3.1 on Motivation and Objectives should be incorporated into the Introduction and Materials and Methods sections to provide background to the study. This section does not present results arising from the experiments undertaken.
Place all scientific names in italics (see Lines 161, 176)
A high proportion of seedlings had no disease symptoms and this may have been from treatment escapes. Data treatment allowed the removal of many of these from the analysis in a reduced data set. This approach warrants more consideration in the Discussion. Furthermore, how did this outcome (% possible escapes) compare with other studies on spore inoculation/wounding of this and other stem pathogens in forestry species? How might inoculation be improved to reduce the number of escapes?
Re deployment: What do we know about the maintenance of resistance with tree age; is nursery resistance a good proxy for field resistance?
Check spelling: e.g. dervied (Line 290)
Author Response
Pitch canker is a very serious disease of pine and although some parts of the world remain free of the pathogen, there remains an urgent need to identify and employ resistant lines of the main plantation pine species and hybrids globally. This paper makes a useful contribution to this field and sets the scene for future breeding strategies. Minor improvements are suggested.
Point 1: Add a new sub-heading between 2.1 and 2.2 for the pathogen. Include here the following: source, isolate age, whether they had been passaged recently through a host and reisolated before use, criteria for isolate selection, known pathogenicity, and related information. Whilst some of this information may be contained in previous studies, it better informs this study to have a reasonable amount of information in parallel with host data in 2.1.
Response 1: This is a good suggestion, especially considering the problems with serial propagation of pitch canker isolates. We have now described the procedure in the methods section.
Point 2: Consider adding a figure so the experimental design & layout is easy for the reader to follow.
Response 2: Good idea - I Inserted a figure to describe design.
Point 3: Was a standard potting mix used as in previous studies?
Point 4: Were the seedlings fertilized?
Point 5: Line 143 – The RSC protocol may not be known to all readers so consider adding a brief description of the height that the stems were cut (they were wounded, or were the tops severed?)
Point 6: Line 144 – how much inoculum did each stem receive?
Responses 3-6: Responding to these four comments together. We have now included a description of plant growth, inoculum bulking and spraying methods. The seedlings were grown in the same way as all other RSC studies; the principal difference is that they were randomized into trays instead of keeping 20-tray blocks.
Point 7: The information content in Section 3.1 on Motivation and Objectives should be incorporated into the Introduction and Materials and Methods sections to provide background to the study. This section does not present results arising from the experiments undertaken.
Response 7: Well noted; I moved this text to the introduction and the accompanying figure to the appendix section.
Point 8: Place all scientific names in italics (see Lines 161, 176)
Response 8: Corrected, and other taxonomic nomenclature re-checked.
Point 9: A high proportion of seedlings had no disease symptoms and this may have been from treatment escapes. Data treatment allowed the removal of many of these from the analysis in a reduced data set. This approach warrants more consideration in the Discussion. Furthermore, how did this outcome (% possible escapes) compare with other studies on spore inoculation/wounding of this and other stem pathogens in forestry species? How might inoculation be improved to reduce the number of escapes?
Response 9: We debated this point internally before submission; the problem is that most plausible explanations are speculative. There was no geometric pattern for escapes (rows or columns) and there is a relative dearth of published data for escape rates. If the reviewer is aware of this type of data, it would be very helpful for us to inform strategy for follow-up studies. As it stands, I would be uncomfortable speculating beyond the scope of data we present. One potential approach to improve inoculations is to drop a fixed amount of the spore solution directly onto the cut stem. This will be tested in the future.
Point 10: Re deployment: What do we know about the maintenance of resistance with tree age; is nursery resistance a good proxy for field resistance?
Response 10: As of now we know very little. The literature is sparse concerning realized genetic gain for this trait, and it’s confounded with the behavior of PPC: occurring in episodes, infections at virtually any age, and not measurable in progeny tests. Unlike rust, infection could happen at any time. A survey of this type of data would be a helpful addition to the literature.
Point 11: Check spelling: e.g. dervied (Line 290)
Response 11: Thank you for spotting this. It is unclear how this did not get caught on an initial spell check, and the manuscript was reviewed for other misspellings.
