Impact of Temperature on Podding in Faba Bean (Vicia faba)
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsIt is unclear why these data are being published over a decade after the actual experiments were conducted. It seems to be an elegant study to quantify temperature responses of podding in faba bean but some of the methodology needs clarification and alternative interpretations need to be discussed.
Methods
L71. If no mineral fertilizers were applied it implies that the soil was relatively fertile. How did you ascertain that there were no nutrient deficiencies, particularly of P, that could have interacted with flowering and podding? Also was the Rhizobium inoculation effective in satisfying the plants’ N requirements?
L81. Why not 4th or 5th row, nearer the centre of the crop?
L92-3. If a pod was produced at a node then it must have been preceded by a flower.
L100-2. Irrigation is not mentioned as a treatment. Was the current study a component of a larger experiment with irrigation treatments? If so, need to clarify.
L 103-8. Need to elaborate on how podding proportion was calculated. Also need to explain the rationale of plotting against average minimum or maximum temperature over 7 or 10 days. Wouldn’t the absolute lowest or absolute highest temp. have a greater effect on pod set than an average over several days? For example, there could be a period with one frost day, killing flowers or pods then, but with the remainder of the days in the given period being above average, to give an overall moderate average score.
Results
Figs 1 &2. Why is there a decline in pod set in the higher range of minimum temps? One would think podding would be improved in this higher range.
Discussion
Need to discuss the relevance of plotting pod set against minimum or maximum temps averaged over 7 or 10 as compared with an absolute minimum or maximum temp.
Author Response
Methods
comment L71. If no mineral fertilizers were applied it implies that the soil was relatively fertile. How did you ascertain that there were no nutrient deficiencies, particularly of P, that could have interacted with flowering and podding? Also was the Rhizobium inoculation effective in satisfying the plants’ N requirements?
Response - Faba beans at theses sites and in north-west New South Wales generally have been found to be unresponsive to mineral fertilizer and so none was applied. This is the practice of growing faba bean in this region. Faba bean are known to nodulate freely and effectively and the trials showed no signs of N deficiency.
comment L81. Why not 4th or 5th row, nearer the centre of the crop?
Response - This allowed us the to leave 4 rows ( the width of a plot harvester) untouched in order for grain harvest thus giving better yield estimates.
comment L92-3. If a pod was produced at a node then it must have been preceded by a flower.
Response - Yes, but we needed to record a time of flowering to use in the analysis. We recorded the date at which a flower was first observed at a node. This has been described in lines 85-94.
comment L100-2. Irrigation is not mentioned as a treatment. Was the current study a component of a larger experiment with irrigation treatments? If so, need to clarify.
Response - Irrigation was applied as and when needed, but it was not a treatment for this study.
comment L 103-8. Need to elaborate on how podding proportion was calculated. Also need to explain the rationale of plotting against average minimum or maximum temperature over 7 or 10 days. Wouldn’t the absolute lowest or absolute highest temp. have a greater effect on pod set than an average over several days? For example, there could be a period with one frost day, killing flowers or pods then, but with the remainder of the days in the given period being above average, to give an overall moderate average score.
Response - The podding portion is the portion of nodes (at any nodal position) flowering on a particular day that then went on to produce a pod at that same node. Those portions were then compared to the temperature parameter existing on that same day.
Yes, there would have been value in using absolutes but that was not done in this study.
comment Results
Figs 1 & 2. Why is there a decline in pod set in the higher range of minimum temps? One would think podding would be improved in this higher range.
Response - The decline in podset at higher temperatures is probably due to excessively high temperatures in spring, declining moisture and forcing maturity. This has beed aded in the manuscript in line 199-201. The temperatures below the optimum are more informative in this study.
comment Discussion
Need to discuss the relevance of plotting pod set against minimum or maximum temps averaged over 7 or 10 as compared with an absolute minimum or maximum temp.
Response - This is a good point and in hindsight we should have done the analysis using absolute maximums and minimums. But at that time, we thought avaerage temperature over several days would provide a better estimate than relying on a single day.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript is of particular interest to specialists, but unfortunately it is not entirely clear which research has been conducted: fundamental or applied.
If this is fundamental research, then you need to add information about which physiological processes in plants are affected by temperature maxima and minima.
How plants tolerate stress and how it is related to the characteristics of the studied plant varieties and how temperature stress affects plant morphology.
It is advisable to add photos of plants to illustrate your conclusions.
If this is a practical task, you can give a variant of the climatic scenario for the studied area and the value of the maximum temperature that will be for the next 5-10 years. Based on the climate forecast, select the most promising plant varieties for breeding to adapt agriculture to climate change.
Or give practical recommendations to breeders based on the current climatic situation.
Or it is proposed to make a list of suitable territories for each plant species which you studied.
I hope my recommendations will help improve your manuscript.
Author Response
comment - The manuscript is of particular interest to specialists, but unfortunately it is not entirely clear which research has been conducted: fundamental or applied.
Response - The research is applied as it seeks to define the temperature limitations for successful flowering and podding in faba bean. This would enable breeders to breed genotypes better adapted to the environment.
comment - If this is fundamental research, then you need to add information about which physiological processes in plants are affected by temperature maxima and minima.
this research is more applied in nature.
Response - This research is more applied in nature.
comment - How plants tolerate stress and how it is related to the characteristics of the studied plant varieties and how temperature stress affects plant morphology.
Response - Faba bean genotypes developed in Australia tolerate heat stress by flowering early in the growing cycle before the onset of heat and tolerate cold by producing and excess of flowers enabling those lost to frost to be compensated for by additional flowering. This has been decribed at line 44 of the manuscript.
comment - It is advisable to add photos of plants to illustrate your conclusions.
Response - Unfortunately, we did not take such photos during the experiment and cannot be included here.
comment - If this is a practical task, you can give a variant of the climatic scenario for the studied area and the value of the maximum temperature that will be for the next 5-10 years. Based on the climate forecast, select the most promising plant varieties for breeding to adapt agriculture to climate change.
Response - We have added folowing sentences in the manuscript in relation to it (line 230-236).
'The long time climate forecast indicates that average temperature in New South Wales will increase by 1.3 °C to 4 °C depending upon the emission level and the temperature increase will occur more in the inland region where faba bean is grown than the coastal region. With the increase in average temperature, the minimum temperature will also increase leading to the decrease in the number of cold nights. This may be good for the pod set in faba bean as the increased minimum temperature will lead to more pod set'.
comment - Or give practical recommendations to breeders based on the current climatic situation.
Response - Addressed the earlier point. But it can be advised that breeding for tolerance to low temperature is more important than high temperature for pod setting for faba bean in sub-tropical region of Australia. This has been added in ther manuscript (line 197-198).
comment - Or it is proposed to make a list of suitable territories for each plant species which you studied.
Response - It is not possible to breed a specific variety for a localised area and the variety recommendation should involve a large region, especially in Australia due to a vast teritory.
comment - I hope my recommendations will help improve your manuscript.
Response - Thank you for your constructive and useful comments to improve the manuscript.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe chosen theme is interesting and useful for bean growers. However, why are you publishing this research so late? After more than 10 years since the experiment.
• What is the main question addressed by the research? This research aimed to determine the minimum, optimum and maximum temperature ranges for optimum bean flowering and pod formation in the field by evaluating the flowering and pod setting at different temperatures of 3 bean genotypes at two locations in Australia on during 2012 and 2013. A question for the authors is: why did it take so long to publish the results?
• Do you consider the topic original or relevant to the field? Does it address a specific gap in the field? Please also explain why this is/ is not the case. The subject addressed has a moderate originality. There are few works in the specialized literature about the biology of the grain and especially about the role of temperature in the flowering of grain plants and the formation of pods in the field. Even more so for the specific conditions in Australia, for farmers and researchers here the results obtained can be relevant. By referring to this area, the results may also be useful for agriculture in other areas with similar climatic conditions.
• What does it add to the subject area compared with other published material? As we said above, compared to the existing information in this field, the present work brings additional and niche information regarding the role of temperatures during the period of flowering, fertilization and pod formation in grain. The information provided is important both for breeders of future bean varieties and for bean farmers.
• What specific improvements should the authors consider regarding the methodology? What further controls should be considered? Future research in this area could study more genotypes and possibly the influence of irrigation on fertilization and pod formation.
• Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed? Please also explain why this is/is not the case. The conclusions are consistent with the conducted experiment and respond to the proposed objective.
Author Response
Comment - The chosen theme is interesting and useful for bean growers. However, why are you publishing this research so late? After more than 10 years since the experiment.
Response - The main author had been on other duties for some years and have only recently got back to this work, however in the intervening period little further research has been done on this subject by others. As this is still relevant research, we decided to publish it now.
Comment - • What is the main question addressed by the research? This research aimed to determine the minimum, optimum and maximum temperature ranges for optimum bean flowering and pod formation in the field by evaluating the flowering and pod setting at different temperatures of 3 bean genotypes at two locations in Australia on during 2012 and 2013. A question for the authors is: why did it take so long to publish the results?
Response - As above, The main auithor was on others duties for some years and have only recently got back to this work, however in the intervening period little further research has been done on this subject by others.
Comment - • Do you consider the topic original or relevant to the field? Does it address a specific gap in the field? Please also explain why this is/ is not the case. The subject addressed has a moderate originality. There are few works in the specialized literature about the biology of the grain and especially about the role of temperature in the flowering of grain plants and the formation of pods in the field. Even more so for the specific conditions in Australia, for farmers and researchers here the results obtained can be relevant. By referring to this area, the results may also be useful for agriculture in other areas with similar climatic conditions.
Response -
Whilst the work may not be particularly original there has been relatively little research done on faba bean generally and in particular on the temperature limits within which it will flower and set pods in the field condition. Not much research has been done in field condition in this area and it does fill a gap. Whilst faba bean is a minor crop in Australia it nonetheless has an important role in crop rotations in certain areas. The research is most relevant to Australia where faba bean is planted in the autumn and commences flowering during the winter months resulting in frost damage to flowering structures. In other parts of the world faba bean is planted in the springtime and flowers during the summer when low temperatures are not limiting to podset. In these environments however the data we have collected on the impact of higher temperatures on podset in faba bean will be relevant. The research is relevant to breeders as it enables them breed genotypes with appropriate length of time to flowering. For farmers this work allow timing of sowing to be optimimal.
Comment - • What does it add to the subject area compared with other published material? As we said above, compared to the existing information in this field, the present work brings additional and niche information regarding the role of temperatures during the period of flowering, fertilization and pod formation in grain. The information provided is important both for breeders of future bean varieties and for bean farmers.
Response - In comparison to other work this research provides more specific data on the temperature regimes which allow successful flowering and podding in the Australian environment. Limited research of this kind has been done around the world and even less in Australia. We feel that this research provides an important contribution to Faba bean resaerch and production.
Comment - • What specific improvements should the authors consider regarding the methodology? What further controls should be considered? Future research in this area could study more genotypes and possibly the influence of irrigation on fertilization and pod formation.
Response - In hindsight the temperature parameter against which podding was measured could have been better selected. Inclusion of more Genotypes would be beneficial, however this study did include a range of maturities that covered the portfolio of genotypes used in Australia. It is unlikely that fertilisers would have a large impact on flowering and podding in faba beans in situations other than severe deficiency. Irrigation would also have limited influence although abundant moisture may allow flowering and podding into higher temperatures in spring. It is worth noting that the Breeza site used in this study has relatively good rainfall and soils with high moisture holding capacity.
Comment - • Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed? Please also explain why this is/is not the case. The conclusions are consistent with the conducted experiment and respond to the proposed objective.
Response - The authors feel that the paper is a well targeted relevant and self supporting piece of work. We started by outlining the limitations to faba bean production in Australia ie low temperatures impacting flowering and podding in winter and high temperatures similarly impacting flowering and podding in spring and early summer. This means that knowledge of the impact of temperature on flowering and podding in Australia is significant and this work at set out to establish the impact of those temperature regimes yield formation. Over and three half thousand flowering sites were observed over two years at two different sites within the production area and extensive statistical analysis by Professor Richard Trethowen established links between temperatures observed in the field and faba bean podding. This work enabled us to reliably conclude that potential exists in Australia for the cultivation of shorter season Faba bean varieties which can form yield during winter and spring before the onset of higher temperatures.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsImprovements made on the basis of comments in the first review are satisfactory, although this reviewer remains uneasy that plots against absolute maximums and minimums were not done.
