Influence of Field and Storage Diseases and Pests on Tuber Yield and Quality of Exotic and Local Yam (Dioscorea spp.) Genotypes

Round 1

Reviewer 1 Report

Yam, belonging to the Dioscorea spp. genus, encompasses a wide variety of species that hold significance as both nourishing foods and sources of bioactive compounds with diverse applications. Its nutritional contribution is noteworthy, serving as a valuable source of carbohydrates for populations across tropical and subtropical regions particularly in Sub-Saharan Africa, where it plays a pivotal role in sustaining the livelihoods of numerous farmers, including those in Sierra Leone. However, the rise in the prevalence of foliar and tuber-related pests and diseases, both within cultivation fields and during storage, stand out as prominent factors curtailing the potential for enhanced productivity. This research confirmed that both field- and storage-related diseases and pests have a substantial impact on the quantity and quality of tuber production in both exotic and indigenous yam varieties, therefore, highlighting the potential for selecting and utilizing elite genotypes in the enhancement of the crop's genetic traits. This manuscript will be of interest to a broad range of scientists who work on horticulture, breeding, plant disease management and postharvest biology of yam. I recommend acceptance for publication.

Minor comments:

Figure 1 and 2, please also indicate yam genotypes and disease severity scores. Place legends under the Figures.

Check the reference in the caption of Table 4, whether it is necessary and place it in text.

Many typos/grammatical mistakes were spotted, although they don't affect the quality of the study. The authors need to check and edit their work carefully and thoroughly.

Minor editing of English language required.

Author Response

Dear Reviewer,

Thanks very much for your inputs. Your concerns have been addressed in the annotated manuscript.

Kind regards,

Francess

Author Response File: Author Response.docx

Reviewer 2 Report

Overall Comments: Saffa et al. present a comparative evaluation of various cultivars of Yam (Dioscorea spp.) and test their susceptibility to anthracnose and yam mosaic virus in the field during different periods of growth. They also test the impact of post-harvest stresses including dry rot, mealy bug and nematode infestation on the cultivars. The manuscript needs to present more data for the post-harvest experiments and there are improvements that need to be made in terms of the explanation and data presentation. Below are specific comments to improve the manuscript.

Specific comments:

·         Methods 2.2: Table 1. Please explain some of the origin of the cultivars used in the study. This could include some explanation about the categories of cultivars (TDa, MOSLY, etc.) and their relative level of susceptibility or other information about the traits bred into them.

·         Results Table 2 and Table 7: These tables should be explained in further detail in terms of the measurement categories presented in the headers. A graphical representation will be more suitable for it.

·         Tables 3-6 don’t have any standard deviation information. This could help show the differences between the biological replicates. A column outlining the standard deviation should be added to this.

·         Table 7 shows the intercept of the data for storage diseases. However the data collected for Dry rot, mealy bug and nematode pressure is not presented. Further it should be explained how the tubers were rated in terms of the post-harvest stress. And if one cultivar or one batch of stored tuber was rated for all 3 post-harvest issues or would the most abundant one be considered the main stressor.

·         There needs to be more of an explanation about the post-harvest data collection in the methods section and the data for the cultivars including standard deviation, relative pressure of each post-harvest issue on each cultivar and photos of damage should be included in the manuscript.

·         Table 8 presents general data about the relative temperature and humidity in the growing region, however there needs to be an in depth explanation of how each of the disease pressures are affected by these weather factors. This should include the molecular disease mechanism or epidemiological effect.

·         The discussion and conclusion section should include the historical background and breeding efforts that went into the cultivars evaluated in the study and what was known about their susceptibility previously.  And how they faired compared to any known information about them. Further, the prevalence of these cultivars being used by growers should also be presented.

Author Response

Dear Reviewer,

Thanks very much for your inputs. Your concerns have been addressed in the annotated manuscript. Responses to your comments are higlighted green in the attached document.

Kind regards,

Francess

Author Response File: Author Response.docx

Reviewer 3 Report

This article discusses about the screening of major cultivated genotype of Dioscorea spp. against the two major diseases (YMV and anthracnose) cultivated at Sierra Leone. A total of 113 genotype has been screened in two consecutive year and the result of the disease severity and yield analysis has been performed. The paper is not written well and a significant improvement is needed before it gets final acceptance to Horticulturae, MDPI. The results are poorly described and the authors did not mention anything about confirmation of these two pathogens in symptomatic tissues. In my opinion this MS can not be accepted in the present form.

Major Comment;

Please follow the Horticulture, MDPI Journal template for writing MS. There is no line number is mentioned. (https://www.mdpi.com/journal/horticulturae/instructions).

1.      Page no. 1, Line no. 15; Abstract section; Follow the ICTV guideline for writing virus name. It should not be Y.M.V! Check throughout the MS.

2.      Page no. 1, Line no. 36; “Dioscorea spp.”

3.      Page no. 1, Line no. 40; Please check the reference format of MDPI throughout the MS. This form of font size is not acceptable.

4.      Page no. 2, Line no. 74; Remove extra [

5.      Page no. 2, Line no. 76-77; Most difficult to control with respect to what bacterial, fungal disease or any other factor? In line no. 63-64, the authors have mentioned about the most significant foliar disease in yam is a fungal disease.

6.      Page no. 2, Line no. 78; Remove extra [. The author’s really need to work on the MS formatting.

7.      Page no. 2, Line no. 79-80; “In addition, the International Committee on Taxonomy of Viruses (ICTV) has recognize twenty-five virus species infecting Yam worldwide (https://ictv.global/)”.

8.      Page no. 2, Line no. 82; Do not write (H.T.S). you can simple say (HTS)! Check another place as well.

9.      Page no. 2, Line no. 89; “Dioscorea spp.”

10.  Page no. 2, Line no. 93; above the sea level

11.  Page no. 3, Line no.104; were investigated in this study.

12.  Page no. 3, Line no.110; Species name should be in italics. Table 1 should be presented as landscape form.

13.  Page no. 3, Line no.111; What is this “TDa 00/00103” catalog number? Should be mention on the top of the table.

14.  Page no. 5, Line no.142; Put the formula in a separate paragraph. Field disease severity generally increased with time among all genotypes assessed. The fitted regression model is determine as using this formula; Provide a reference for this.

y= 17.57-0.47 X1-0.87X2+1.48X3 -3.15X4

15.  Page no. 5, Line no.147; Figure 1 and 2 should be cited here!

16.  Page no. 5, Table 2; what does that number signify in parentheses t(108). Need to mentioned in the table or legend.

17.  Page no. 6-8, Table 3 and 4; Both the table should be in landscape mode with full-legend and heading descriptions.

18.  Page no.6-8, Table 3 and 4; The author’s have mentioned the severity scale ranges from 1 to 5, then why you have measure it in decimal format like 1.3, 1.8, 1.5 etc.  Instead of this you can generate AUSPC/AUDPC. Which will give a symptoms progression in the area selected. These values (mild symptoms) are very confusing.

19.  Page no. 9, Line no.174; Did the authors have tested presence of any other virus? If yes, provide the details and put them as supplementary image, if any!

20.  Page no. 9, Line no.174; How you confirmed YMV presence in symptomatic tissues?

21.  Page no. 11, Line no.192; Y.M.V. attack? What is the mode of transmission of YMV?

22.  Page no. 12, Table no. 6; All the table can be presented in landscape view for better presentation. However, based on the symptoms severity progression a graph can be a generated instead of only tables.

23.  Referencing style should be followed as mentioned in MDPI.

This article is not written well.  It needs significant improvements. 

Author Response

Dear Reviewer,

Thanks very much for your inputs. Your concerns have been addressed in the annotated manuscript. Responses to your comments are highlighted green, grey and yellow in the attached document.

Kind regards,

Francess

Author Response File: Author Response.docx

Reviewer 4 Report

-     It would have been welcome to number the lines to make the review easier.

-  Overall the research results are quite amalgamated as pathogens and pests should have been isolated to see the impact of each on the preservation of Dioscorea spp. tubers.

Introduction

-  „Yam production in West Africa dramatically increased from 8.3 million tons in 1961 to 74.2 million tons in 2019 (Adeyinki et al., 2022; FAOSTAT, 2021).”

Why is the term dramatic used? Dramatic means something negative.

- „Yam mosaic virus is a potyvirus originating from Africa, which spreads mainly through the exchange of infected yam germplasm (Mendoza et al., 2022).”

Yet how is it transmitted naturally? Through animal vectors (aphids, pollination), through seeds? It should be noted, based on literature data.

- „However, current knowledge of biology, epidemiology, transmission, symptomatology, and the impact of these viruses on production in single or mixed infections remains insufficient to develop effective control strategies (Darkwa et al., 2020).”

Problems with viruses exist in all plant species, but it cannot be said that there are no effective control methods and no control strategy based on thermotherapy, chemotherapy, apical spikes from meristem cultures, etc. I even recommend the authors to cite authors who have done virus control strategies in Discorea spp. species.

- There are some quotations in brackets that are typed in larger type than the paper. Please standardize!

Material and working method

- Where do the differences in planting distances between species of Dioscorea spp. come from?

- Were the infections/infestations artificial or natural? If artificial, the method should be described. If natural, the biological reservoir of diseases and pests should be detailed.

- By which methods was Yam mosaic virus diagnosed? Were biological, serological, molecular techniques used or was it based on symptoms only?

Results and discussion

- The observed wide variance of anthracnose severity compared to Y.M.V. disease infection, agrees with (Egesi et al., 2007), showing that ranking of genotypes for anthracnose is more likely to change when tested in multiple locations (crossover interactions) thereby justifying the use of site regression model (SREG) (Gauch and Zobel, 1997.

Egesi et al., 2007 should be taken out of brackets. Appears twice in the same paragraph.

Conclusions

However, a few genotypes should be noted which, on the whole, proved to be the most resistant to the diseases and pests studied and which could be recommended for production at this time.

Author Response

Dear Reviewer,

Thanks very much for your inputs. Your concerns have been addressed in the annotated manuscript. Responses to your comments are highlighted yellow in the attached document.

Kind regards,

Francess

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Authors have addressed the comments. 

Reviewer 3 Report

MS is improved significantly. It can be accepted.

Reviewer 4 Report

Congratulations for the research work you have done and for producing this valuable paper!