Morphological Variation of Strychnos spinosa Lam. Morphotypes: A Case Study at Bonamanzi Game Reserve, KwaZulu-Natal, South Africa
Round 1
Reviewer 1 Report
In this manuscript authors studied the morphological diversity of S. spinosa at Bonamanzi Game Reserve, South Africa. The report on variability and heritability among S. spinosa morphotypes is important for future breeding programs. Also, we believe the ideas in manuscript are clearly and accurately communicated without errors in spelling, grammar, and adequate word choice.
Please find below some general and specific comments.
General concept comments
As it is a non-domesticated species, it is important to start a breeding program. In this sense, it would be important that, in the concluding section, the authors specifically point out a group of morphotypes with a reasonable and balanced fruit production in both seasons, that will be the starting point for a breeding program.
in ANOVA analysis did authors test for normality and homogeneity of variances? Which statistics tests did author’s used whit that purpose?
Specific comments
In section 2.1, the authors should indicate the The Köppen–Geiger climate classification of the place where the field experiment was carried out.
There is some confusion in the identification of Figures. Authors should review the document and correct the numbering of figures. Figure 4.3 should be Figure 3 and Figure 4.4 should be Figure 4.
In section 2.1, line 78, please indicate the number of trees studied.
In the tables 3 and 4 authors should use the same number of decimal places for the parameters studied.
In figure 2, similarly to figure 3, the authors should also indicate, through letters, the groups of significant differences. Also in both figure legends should appear the meaning of the letters at the top of the columns.
Section 3.2, first line, please replace “The canopy radius ranged from 3.10 m (GRxCR-dGRO) to 8.50 m”, by “The canopy radius ranged from 3.10 (GRxCR-dGRO) to 8.50 m”
Section 4.1, line 217, replace “… where the height varied between 1.97 m and 4.11 m”, by “… where the height varied between 1.97 and 4.11 m”.
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
I suggest you check the formatting and configuration of the tables. In some tables the variables present in the footer are not described.
The information added in the conclusions is unnecessary. This looks like results description.
Table 1 comprises result and not material and method.
Author Response
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Author Response File: Author Response.docx
Reviewer 3 Report
The aim of the present study was to characterize variability among Strychnos spinosa morphotypes using morphological traits. The authors have done a lot of work on collecting and analyzing the material. The results of the work can become the basis for further selection of Strychnos spinosa. The authors first identified such features as pyriform fruit shape, purple fruit color at immaturity and purple tinge on the immature leaves of some morphotypes. Identifying the diversity of various morphological indicators of plants in situ is a very actual task of modern botany. The authors have received a number of interesting conclusions. I am not an expert in the field of statistics and cannot be fully qualified in terms of the choice of methods for the purity of calculations. Nevertheless the analysis of the results and conclusions seems very logical to me. I think that the manuscript can be accepted for publication after a minor revision (below are my specific comments). I especially want to note that the authors should pay more attention to the literature cited, carefully insert the links and always try to cite the primary sources. The fruits of Strychnos spinosa are not berries, their pericarp is not soft of juicy, it is herd and is usually broken with a hummer or a stone for getting the pulp for food. The authors in the article pay attention to the number and size of seeds, whereas pulp is not described in detail, although namely the pulp is economically valuable. I would like recommend to add the data on pulp (for example, on the ratio of pulp weight and fruit weight, or the amount of pulp and the number of seeds) in the manuscript.
Below is a list of comments. The line and page numbers were displayed incorrectly in my manuscript file, therefore, in order to avoid confusion, I additionally a direct quote from the manuscript for each case.
1. P1L24 ‘A rough rind texture and purple tinge on the immature leaves of some morphotypes was recorded for the first time.’ Here and throughout the text, I propose to replace ‘rind’ with the term ‘pericarp’
2. Page 1 Line 37 (=P1L37). ‘Prolonged droughts have increased because of global warming [3].’ Perhaps it is more appropriate to write ‘global climate change’.
3. P2L47. ‘with a trunk sometimes fluted up to 25 cm in diameter [8].’ The comma after ‘fluted’ may have been omitted. I would recommend rephrase this sentence fragment.
4. P2L53. ‘…classified as spherical green berries [1,11]’. In [1] – Omotayo & Anemu (2021), there is no mention of the fruits of Strychnos spinosa. In [11] – Tittikpina et al. (2020). There is the following sentence: ‘Fruits are greening berries, spherical with the form and the aspect of an orange, turning into yellow at maturity. The pericarp is hard containing several seeds enrobed by edible pulp (Berhaut,1988; Akoégninou et al., 2006)’. Also, for some Strychnos species, fruits were described as follows: ‘pericarp subwoody’ [Brandão, E. D. S., & Rapini, A. (2017). Novelties in Strychnos sect. Breviflorae (Loganiaceae). Phytotaxa, 329(3), 262-268.] or ‘hard-shelled fruits of Strychnos spp.’ [W.C. McGrew (1999) Manual Laterality in Anvil Use: Wild Chimpanzees Cracking Strychnos Fruits, Laterality, 4:1, 79-87, DOI: 10.1080/03069887600760101]. Such a description of the fruit does not allow us to attribute the fruits to berries. Berry (bacca, uva) – the apocarpous or coenocarpous indehiscent fruit without a continuous sclerenchymatous layer (sclerenchyma discontinuous) in the pericarp [sensu Bobrov A. V. F. Ch., & Romanov, M. S. (2019). Morphogenesis of fruits and types of fruit of angiosperms. Botany Letters, 166(3), 366-399.]. The berry may be dry or ‘juicy’, but can not have a ‘hard’ or ‘woody’ pericarp. The anatomy of the fruits of Strychnos spinosa had been ealier studied [Bobrov & Romanov (2019)] and the fruits of S. spinosa are treated as amphisarcas. (Amphisarca – is the coenocarpous indehiscent fruit with the sclerenchymatous topographic zone localized in the main tissue of the epicarp and/or peripheral or middle zone of the mesocarp). The fruits with such characteristics as S. spinosa should not be considered as berries.
5. P2L66. ‘Therefore, the aim of this study was to characterise…’ There is a typo here, you need to: characterize.
6. P2L80. ‘research that was conducted throughout the growing season (July 2018 – April 2019).’ Further in the text there is a mention of season 1 and season 2, but the materials and methods do not disclose what is meant by this. Please clarify. Also, in some parts of the article it is written ‘season one’, and in others ‘season 1'. You need to do the same everywhere. It seems to me that ‘season 1' is better.
7. P2L82. The authors write about immature fruits. Please specify the stage. For example, the number of days after flowering/pollination or before ripening. The authors write: P3L192 ‘However, the exact stage at which the shape changes to roundish and the purple colour begins to fade into green is unknown.’ It shall be specified, at least approximately.
8. P2L82. ‘…was categorised into small (1) and big (2) leaves.’ In other cases, all categories are specified by exact sizes/ranges. Please clarify here.
9. P2L86. ‘Fruit texture was…’ It's a little confusing that in the previous and subsequent sentences the authors specify that the fruits are immature, but here they skip the information. Please clarify.
10. P3L199. ‘Musa itinerans’. Please indicate the author of the species at the first mention.
11. P3L220. ‘Thus, S. spinosa plants is capable of bearing fruits at very short heights, less than 3 m.’ It is not very clearly stated, I would recommend to rephrase this sentence.
12. P4L266. ‘Leaves are green because they contain the green photosynthetic pigments, chlorophyll, which plays a major role in plant growth status [46].’ I would exclude this sentence. It is certainly true, but it seems to me that it is unnecessary to say.
13. P4L269. ‘In the current study fruit number ranged from 1–112 fruits per tree (Figure 2), resulting in fruit yield that ranged from 1–38.45 kg/tree (Figure 3). These values are substantially lower than those reported from in a study in Zimbabwe where a single tree can produce as much as 300–700 fruits, this being approximately equivalent to 40–100 kg/tree [5].’ The difference between fruit number and fruit yield in this study (1-112 fruits per tree and 1-38.45 kg/tree) and the research data in Zimbabwe (300-700 fruits and 40-100 kg/tree) is very significant, as absolutely for each characteristic, but more interesting is the difference in the number of fruits and yield. I would like to clarify what the authors of the article associate with such a difference. Are the fruits of S. spinosa in Simbabve are three times lighter than in Bonamanzi Game Reserve as it comes out from the data provided?
14. P5L290. ‘In the present study it varied from 182–556 g observed by Omotayo and Anemu [1].’ It would be more correct to write ‘from 182 to 556'. It is unclear where this information comes from. Are the data obtained in the present study or gotten from the literature? Please clarify this sentence.
15. P5L293. ‘Strychnos spinosa fruits are covered with a hard woody [1] shell herein referred as the rind.’ The link [1] needs to be moved and put after the ‘shell'. In the article [1] – Omotayo & Anemu (2021); no mention of ‘hard woody shell’ or anything like that. The link may have been mixed up. Probably, there was a reference here [10] – Asuzu & Nwosu (2017), where ‘very hard pericarp' is mentioned. Or [5] – Ngadze et al. (2017); ‘woody shell’, where this thesis is quoted by [Coates Palgrave, K.; Drummond, R.B.; Moll, E.J.; Coates Palgrave, M. Trees of southern Africa. Struik Publishers: Cape Town, 2002; pp 923–935.]
16. P5L299. ‘In this study fruit rind thickness ranged from 2.8 mm to 5.3 mm among the morphotypes (Table 3), which suggests that size of the rind is not constant.’ I would also recommend in future investigations to study the anatomy of fruits with different thickness ‘rind’ (pericarp) to determine the prospects of breeding specific morphotypes with different pericarp thickness. Anatomical data can clarify this.
17. Fig. 3c. I ask you to add scale bars, since the authors emphasize the difference in the size of the leaves, and this is not very clear from the Figures. Also, if possible, I would like more high-quality photos. Since the article is devoted to morphotypes, qualitative illustrations of morphology are extremely necessary.
18. Fig. 3c. It is linked as ‘Fig. 3c.’, and the caption to the figure is titled as ‘Figure 4.3’. Perhaps this is not displayed correctly for me. And check the correctness of links and captions everywhere.
19. Figure 4.4. There may also be a mistake in the caption – Figure 4 follows. I would change the caption to: ‘Mature fruits of Strychnos spinosa with yellow patches: small (a), medium (b) and big (c).’
20. Fig. 2a, b. The authors noted the difference in the color of unripe fruits, but the color rendering is not very clear due to the difference in the parameters of photographing. It would be nice to redo the pictures so that the color difference is more expressive. I also ask you to add scale bars.
21. Table 1. There are gaps in the ‘Leaf size’ column, I don't really understand from the text why the column is lacking the information. Please explain in the text or fill in the gaps.
22. Table 1. Perhaps it would be better to put this table in the supplement.
23. Table 4. Perhaps it would be better to put this table in the supplement.
Author Response
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Author Response File: Author Response.docx
