Forcing Temperature Effects on Plant Development for Containerized Blackberry Grown Using Long-Cane Techniques
Round 1
Reviewer 1 Report
see attachment
Comments for author File: 
Comments.pdf
Author Response
Reviewer #1 Comments
The manuscript by US authors reports on forcing potted blackberry canes after they completed their dormancy. The topic fits the scope of MDPI horticulture. The manuscript is confusing in terms of jargon used. It is not an easy one to understand what the authors mean and may be suitable for publication after major revision or rejected , re-write and clarification of
The authors have gone through and added more text and images, tried to clarify the language and reduce jargon, and modified the descriptions of the modeling parameters and descriptions for easier reading.
- improve title- delete “rate”, consider “ ..forcing temperature on the development of potted blackberry long canes” or similar
The title now reads as “Forcing temperature effects on plant development for containerized blackberry grown using long-cane techniques”
2) keywords: add dormancy and forcing for better visibility of your work
Thank you and this correction was made.
Intro
- Consider substituting “plant development” by “plant growth”, if you mean leaf and shoot growth, whereas development implies leaf, then flowers, followed by fruit and then leaf drop; for development, e.g. daylength is a factor for flower induction
The authors do mean development processes like flower and fruit, and not leaf and shoot growth. No changes were made.
- MDTemperatures over-simplify the situation, as you could have a frost or heat destroying your crop (or induced flowers), which will not show in the MDT- it is better to use e.g. max- min temp values as a range like you did in equation (1) following Joe Landsberg’s work at Bristol
The authors agree that the MDT method may smooth out the effects of extreme heat and frost events that had significant and lasting delays on plant development. We argue in many cases where daily highs are above Tmax or daily lows below Tmin, the corresponding high or low ADT/MDT, respectively, effects would be included in the model if significant over time. We are not sure you intend us to use the max-min values as you stated, those values in Eq 1 simply help define the curve in Figure 1. However, to address this comment we added the following paragraph to the discussion, and welcome any further feedback.
“In some scenarios, using MDT may over-simplify the relationship between temperature and plant development. For example, extreme heat or frost events may cause significant and lasting delays on plant development and may not be well-reflected by MDT, particularly if these events are infrequent and therefore have little weight when determining MDT by averaging the daily ADT values over time. The models developed in this research would be most accurate in predicting the time to first flower and fruit in environments where the ADT was relatively stable over time and where daily temperature highs and lows were mostly within the Tmin (6°C) and Tmax (35°C) parameters used in Eq. [1]. These types of environments may include climate-controlled greenhouses and tunnels with the capacity of protecting crops from extreme weather events.”
M/M
5) line 111 and 118, please explain / clarify the difference between MDT and ADT- is ADT the time between x and y and what is x and what is y and then daily temperature accumulated or averaged?
The difference between ADT and MDT was highlighted and this sentence was added “ADT refers to a daily 24-hr average temperature measurement, which fluctuated over time in this study, and therefore the mean daily temperature (MDT) was also determined by taking the average of the daily ADT values from the time plants were removed from cold storage up until first open flower and first ripe fruit for each plant.”
Results
6) lines 128- 134- there is no parameter C, as given in table 2
Parameter C was in Equation and has been redefined more accurately as Rmin, the minimum rate of development estimated using non-linear regression. See response to other reviewer and changes made to this section.
7) line 180- should this be table 2 , not table3
Yes, thank you and this correction was made.
8) Table 2 gives two values for each of the three parameter A-c, what is the difference for the repetition of the columns?-
For each cultivar, two models were developed, one to predict time to first flower and the other to predict time to first fruit. Labels were included in Table 2 already, but we added a header line to clarify with parameters (A, B, Rmin) belonged to which model (flower or fruit).
9) Table 1 and text line 156, please explain whether this is the average MDT between plant release from the last day in cold store and emergence of the first flower/ fruit – if so, this should be ADT-correct? See confusion arisen in M/M 5) Make it clear, what you mean e.g. by “- MDT is the time /temperature calculated from daily min by the Linvil method and the xyz e.g. mean daily temperature- accumulated (or averaged?) over the 30 days between release from cold store and first flower/bud (BBCH 59)
_ ADT in contrast is the time /temperature of what ..”
The difference between ADT and MDT was clarified in the Materials and Methods, see previous comment. Changes to Table 1 header were made to clarify, and now reads as follows: “Table 1. Mean daily temperature (MDT, in °C) at first open flower and ripe fruit and the time (in days, d) from the last day of cold storage to first flower and fruit for dormant blackberry cultivars forced in a controlled-environment greenhouse (Location 1) and in an unheated high tunnel (Location 2). The rate of progress towards first flower and fruit were calculated as the reciprocal of time to flower and fruit, respectively (1/d). Sample sizes (n) were four and six for Locations 1 and 2, respectively. Values in parentheses indicate ±1 standard deviation. Location 1 is Greenhouse and Location 2 is High Tunnel.”
Reviewer 2 Report
1. The first sentence seems to have too many citations and insufficient induction and discussion in the main text.
2. What are the applicable crops and are they universal in figure 1？
3. Highlight the innovation points of this manuscript.
4. What does C mean in Eq. [2]? How are values determined?
5. Values in parentheses indicate ±1 standard deviation? ±1 standard deviation? in Line 195/206.
6. RMSE was commonly used between the observed and measured values.
7. This model only considers temperature, does other factors also affect the results.
8. The discussion needs to be further enriched.
9. What are the environmental conditions during the experiment?
English needs tto be improved.
Author Response
Reviewer #2 comments
. The first sentence seems to have too many citations and insufficient induction and discussion in the main text.
The first sentence has been broken up and expanded upon in response to this and another reviewer’s comments.
- What are the applicable crops and are they universal in figure 1？
The trends are highly common across crops and systems, but in this case we are referring to blackberry (Rubus sp.) crops. In Figure 1 caption we corrected the first sentence to clarify this point, it now reads “Representation of temperature effects on plant development rates based on parameters suggested for Rubus sp. by Black et al. [18].”
- Highlight the innovation points of this manuscript.
The following sentence was added to the conclusions and abstract to highlight the major innovation of this work. “To our knowledge, this study was the first to characterize the relationship between temperature and crop timing for long-cane blackberry.”
- What does C mean in Eq. [2]? How are values determined?
C is actually Rmin, the minimum rate at which plant development occurs above zero, estimated using non-linear regression. This change was made throughout the article.
- Values in parentheses indicate ±1 standard deviation? ±1 standard deviation? in Line 195/206.
This sentence was moved from the footer to the table header as requested.
- RMSE was commonly used between the observed and measured values.
The authors did not use RMSE to evaluate model accuracy, but rather by measuring the difference between predicted and observed values. Computing RMSE would have yielded similar results, but the authors method is simpler and more applied for horticultural practitioners, for example, the readers can directly see how many days or weeks by which the model is inaccurate and relate these findings to their business or research. No change was made.
- This model only considers temperature, does other factors also affect the results.
Other factors were considered and discussed at line 258. However, the discussion was enriched to add more detail per this and another reviewers request, and more factors and the limitations of our methods were expanded upon.
- The discussion needs to be further enriched.
See response to the previous comment.
- What are the environmental conditions during the experiment?
The temperature and light conditions during the experiment were added to the materials and methods section.
Round 2
Reviewer 1 Report
Authors have improved their manuscript, changed the title and explained their jargon- the alleged difference between ADT and MDT still remains somewhat obscure to me. Authors may want to check on previous dormancy work on blackberry- this has been studied before, maybe without specifying the type of growing medium.
Author Response
Reviewer #1:
Authors have improved their manuscript, changed the title and explained their jargon- the alleged difference between ADT and MDT still remains somewhat obscure to me. Authors may want to check on previous dormancy work on blackberry- this has been studied before, maybe without specifying the type of growing medium.
ADT is the simple average temperature over a 24 hour period. If you have a week’s worth of ADT values that differ day-to-day slightly, for example, the MDT is the average of the ADTs over that week to come up with the average ADT experienced by plants. The same concept was applied to calculate the average ADT at the point of flower and fruit.
Based on reviewer comments, the MDT concept was confusing when compared to ADT. Therefore, the authors removed all mention of MDT and simply described this concept as ADT or the average ADT up to the point of flower or fruit.
Reviewer 2 Report
1. Forcing temperature? the title should be re-considered.
2. The data in table 1 and table 2 was not easy for readers to understand.
3. Significant deviation was observed in Predicted minus observed days in table 3.
4. Is it accurate to only use temperature to estimate the model due to significant changes in other environments? How applicable is it?
Author Response
Reviewer #2:
Forcing temperature? the title should be re-considered.
This change was made per another reviewer’s request and reflects the correct language when taking a dormant plant and placing it in an environment to encourage reproductive growth, as discussed in the Introduction. No change was made.
- The data in table 1 and table 2 was not easy for readers to understand.
The way tables 1 and 2 are set up is the same as other temperature modeling studies (see references 16, 24 through 26). During the last review, we added more detail to clarify which parameters belonged to which type of model (flower or fruit) per the comments of another reviewer. If the reviewer has a specific type of suggestion to clarify the data, or can identify what is confusing, we welcome that kind of feedback and can make changes. No changes made currently.
- Significant deviation was observed in Predicted minus observed days in table 3.
Yes, and we discussed this variability in the Discussion. We will add more text to highlight more some of this variability.
- Is it accurate to only use temperature to estimate the model due to significant changes in other environments? How applicable is it?
There has been a lot of research highlighting that temperature is the primary environmental parameter influencing growth and development rates. However, other variables do have influence, which we aimed to discuss but can add more text to highlight this in the Discussion and Conclusions. Using temperature only is a simple approach to this type of modeling and very common, for example, growing degree day and heat unit models are used extensively in agriculture for tracking plant development and only include temperature.
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