Cultivar Mixture Enhances Crop Yield by Decreasing Aphids

Round 1

Reviewer 1 Report

Accept with suggested revisions as indicated

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

 

We are very grateful to you for giving us the opportunity to revise our manuscript (agronomy-1554344: Cultivar Mixture Enhances Wheat Yield by Decreasing Cereal aphids). We appreciate you for the critical and constructive comments and suggestions on our manuscript.

 

We have considered each comment carefully and have made substantial revisions to our paper as a consequence. The following are the responses and revisions I have made in response to the reviewers’ questions and suggestions on an item-by-item basis. We hope this revision has produced a reasonable article to Agronomy.

 

Kindly regards,

 

Zihua Zhao, also on behalf of co-authors

China Agricultural University

 

 

 

Reviewer’s Comments to Author:

Reviewer: 1

Comments to the Author

Line 36, please delete “to a large extent”

 

Reply: Agree and done.

 

Line 50-51, please delete “be more possible to adopt by” and add “have more potential to be adopted by”

 

Reply: Agree and done.

 

Line 56, please add “s” behind “Mixture” 

 

Reply: Agree and done.

 

Line 57, please add “versus” before “monocultures” 

 

Reply: Agree and done.

 

Line 59-62, “Moreover, aphids, which belong to hemipterans and share more attributes of pathogens than other insect species, may be more vulnerable to the effect of cultivar mixtures with different susceptibility to crop diseases, and cereal aphids have been reported to limit the production of wheat in China.” Re-word and be more specific 

 

Reply: Thanks to reviewer for reminder, we had re-worded and made the expression more specific. Moreover, aphids that belong to hemipterans share more attributes of pathogens than other insect species, so aphids may be more vulnerable to the effect of cultivar mixtures with different susceptibility to crop diseases, and it has been reported that cereal aphids limit the production of wheat in China. Therefore, it is reasonable to take wheat and cereal aphids as the research object to explore the effects of cultivar mixtures with different susceptibility to crop diseases on insect pests and crop yield.

 

Line 87, please delete “at” and add “in”

 

Reply: Agree and done.

 

Line 89, please delete “probably providing” and add “which provides”

 

Reply: Agree and done.

 

Line 93, please delete “crops” and add “plots”

 

Reply: Agree and done.

 

Line 101-102, please delete “susceptibility”, “resisitance” and add “susceptible”, “resistant” respectively

 

Reply: Agree and done.

 

Line 123, please delete “investigations” and add “samples”

 

Reply: Agree and done.

 

Line 134, please delete “was” and add “were”

 

Reply: Agree and done.

 

Line 213, please delete “with years significantly” and add “significantly with years”

 

Reply: Agree and done.

 

Line 225, please delete “scouring” 

 

Reply: Agree and done.

 

Line 227, please add “s” behind “aphid” 

 

Reply: Agree and done.

 

Line 233, please delete “a” 

 

Reply: Agree and done.

 

Line 242, please add “s” behind “population” 

 

Reply: Agree and done.

 

Line 242, please delete “was” and add “were”

 

Reply: Agree and done.

 

Line 266, please delete “s”  

 

Reply: Agree and done.

 

Line 266, please delete “possessed high” and add “possess increased”

 

Reply: Agree and done.

 

Author Response File: Author Response.docx

Reviewer 2 Report

Introduction:

1.Pest damage can cause an average of 15% reduction in crop production (reviewer suggestion:- main pests to be listed);

 2. Sitobion miscanthi and Rhopalosiphum padi. (reviewer suggestion- add sistematic informations when first mentions);

3.  In this study, we conducted two-year field experiments to study how wheat cultivar mixtures with different susceptibility to wheat stripe rust disease (reviewer suggestion- add the latin name of rusttisease)

Mąterials and methods: 

1. 2.2. Aphid Abundance (reviewer suggestion: there are 2 aphids listed: did authors plan to evaluate % difference between this two species ? Is there dominant species, is there third species of aphids.
2. Add the methods for rust disease survey since the results are presented.

Results:

1.   The aphid abundance in 2019 was significantly higher in the "susceptible wheat treatment" than in other treatments. (reviewer suggestion: There are 3 susceptible cultivars), are those there merged when showing results, would be usefull to explain this
2.   the 5-cultivar mixture showed significantly lower
   aphid abundance compared with susceptible or resistant wheat treatment (F2,117 =12.111): It is not clear to which treatment this number 12.111 refer; same with  18.214 and  10405 ± 237):reviewer suggestion - add the table with data on aphid number for each treatment or make the the text more understandable to the reader.  Value 10405 ± 237 is the only value having SE, unclear.
3.  In 2020, the yield of 5-cultivar mixture was 30.3% higher than that of resistant wheat treatment (Figure 3). reviewer: did author by mistake refer to 2020 instead 2019. Would be suggested that when state percentage between 5CM and R and S, stress percentage  difference also for S.Discussion: 
4. The annual variation in aphid population numbers was associated with temperature,  reviewer suggestion: Are there existing temperature data for Kaifeng experimental station for 2019 and 2020
5.  Unexpectedly, more aphid population was observed in the disease-susceptible varieties than the other varieties. reviewer - please explain "unexpectedly.
6. conclusions: Are there conclusions for this research. Some conclusion statements are stated in abstract as follows " The results showed that cultivar mixture significantly decreased aphid abundance compared with the single varieties (resistant/susceptible). Cereal aphids decreased wheat yield by 8%, while cultivar mixture increased wheat yield by 5%. Additionally, cultivar mixture had significantly higher thousand-grain weights than susceptible and resistant wheat varieties in 2019 and 2020. Cultivar mixture enhanced wheat yield by decreasing cereal aphids, indicating a bottom-up or top-down effect from genetic diversity to pest abundance. Our results indicated that appropriate cultivar mixtures could manage insect pests to some extent and stabilize crop yield". reviewer suggestion: Explain in results 5 and 8 percent values from abstract and make conclusions.
     

Author Response

Dear Reviewer,

 

We are very grateful to you for giving us the opportunity to revise our manuscript (agronomy-1554344: Cultivar Mixture Enhances Wheat Yield by Decreasing Cereal aphids). We appreciate you for the critical and constructive comments and suggestions on our manuscript.

 

We have considered each comment carefully and have made substantial revisions to our paper as a consequence. The following are the responses and revisions I have made in response to the reviewers’ questions and suggestions on an item-by-item basis. We hope this revision has produced a reasonable article to Agronomy.

 

Kindly regards,

 

Zihua Zhao, also on behalf of co-authors

China Agricultural University

 

 

 

 

Reviewer’s Comments to Author:

Reviewer: 2

Comments to the Author

1. Pest damage can cause an average of 15% reduction in crop production (reviewer suggestion:main pests to be listed);

 

Reply: Thanks to reviewer for reminder, we had listed several main pests on major grain crops. Cereal aphids, corn borers, and rice planthoppers have unfavorable effects on crop yield.

 

2. Sitobion miscanthiand Rhopalosiphum padi. (reviewer suggestion- add systematic information when first mentions);

 

Reply: Agree and done. We had added systematic information. Sitobion miscanthi (Hemiptera: Aphididae) and Rhopalosiphum padi Linnaeu.

 

3. In this study, we conducted two-year field experiments to study how wheat cultivar mixtures with different susceptibility to wheat stripe rust disease (reviewer suggestion- add the Latin name of rustdisease)

 

Reply: Agree and done. We had added the Latin name of rust disease.

 

Materials and methods:

 

2.2. Aphid Abundance (reviewer suggestion: there are 2 aphids listed: did authors plan to evaluate % the difference between these two species ? Is there dominant species, is there third species of aphids.

 

Reply: Through field investigation, Sitobion miscanthi, Schizaphis graminum, and Rhopalosiphum padi. were found in Kaifeng wheat field. Sitobion miscanthi and Rhopalosiphum padi. are the dominant species in Kaifeng wheat field while the occurrence of Schizaphis graminum was too low, so the abundance of Schizaphis graminum had not been investigated. One of the research objectives was to determine the interaction between wheat and cereal aphids and we did not plan to evaluate % the difference between these two species in this research. Your opinion is very valuable, which is our next research direction.

 

Add the methods for rust disease survey since the results are presented.

 

Reply: Agree and done. We added the specific methods for rust disease survey in this part. 

2.4 Rust disease survey

At the jointing stage, the stripe rust races CYR32, CYR33, and CYR34 (1:1:1) were artificially inoculated. Mingxian 169 was planted in each plot center as the induction center. Slides were placed at different distances from each plot to the disease center, and 3 replicates were set with 3-10 sampling points. Spore sampler and disease assessment were carried out several times after onset. The number of diseased leaves and severity were recorded, and the severity evaluation criteria were divided according to the size of summer spore heap in leaf area, namely 0, 1%, 5%, 10%, 20%, 40%, 60%, 80%, and 100%. Then calculate the incidence and disease index, the formula referred Gu[32].

 

Gu, Y.L.; Chu, B.Y.; Wang, C.C.; Li, L.F.; Zhou, Y.L.; Luo, Y.; Ma, Z.H. Spore concentrations of Blumeria graminis f. sp. tritici in relation to weather factors and disease development in Gansu, China. Can. J. Plant Pathol. 2020, 42, 52–61. [CrossRef]

 

Results:

 

The aphid abundance in 2019 was significantly higher in the "susceptible wheat treatment" than in other treatments. (reviewer suggestion: There are 3 susceptible cultivars), are those there merged when showing results, would be useful to explain this.

 

Reply: The data of susceptible cultivars were merged to show the results as the goal of us was to promote the appropriate cultivar mixtures, so the data of each susceptible cultivar did not be analyzed separately.

 

 

The 5-cultivar mixture showed significantly lower aphid abundance compared with susceptible or resistant wheat treatment (F2,117 =12.111): It is not clear to which treatment this number 12.111 refer; same with 18.214 and 10405 ± 237): reviewer suggestion - add the table with data on aphid number for each treatment or make the text more understandable to the reader. Value 10405 ± 237 is the only value having SE, unclear.

 

Reply: “A 2019/4/17 (F_2,117=20.182, P<0.001); 2019/4/23 (F_2,117=6.758, P=0.002); 2019/4/29 (F_2,117=3.518, P=0.033); B (F_2,117=17.046, P<0.001); C 2020/4/14 (F_2,117=14.201, P<0.001); 2020/4/20 (F_2,117=6.134, P=0.003); 2020/4/26 (F_2,117=12.111, P<0.001); D (F_2,117=18.214, P<0.001).” and “A total of 2447±134, 1689±62, 1853±108 (Figure 1B) and 10405±237, 9366±113, 8343±336 (Figure 1D) were reached in individuals per 100 tillers of the aphid abundance from susceptible treatment, resistant treaetment, and 5-cultivar mixture in 2019 and 2020 respectively.” were added to express clearly.

 

In 2020, the yield of 5-cultivar mixture was 30.3% higher than that of resistant wheat treatment (Figure 3). reviewer: did author by mistake refer to 2020 instead 2019. Would be suggested that when state percentage between 5CM and R and S, stress percentage difference also for S.

 

Reply: Thanks to reviewer for reminder, we have verified the data of wheat yield and calculated again, and confirmed that we had not referred to the wrong year. We also added the percentage difference between 5-cultivar mixture and susceptible treatment. In 2020, the yield of 5-cultivar mixture (0.258kg/m²) was 30.3% higher than that of resistant wheat treatment (0.198kg/m2) and 5.7% higher than that of susceptible wheat treatment (0.244kg/m²). In 2019, the yield of 5-cultivar mixture (0406kg/m²) was 42.5% higher than that of resistant wheat treatment (0.285kg/m²) and 21.6% higher than that of susceptible wheat treatment (0.334kg/m²).

 

Discussion:

The annual variation in aphid population numbers was associated with temperature,  reviewer suggestion: Are there existing temperature data for Kaifeng experimental station for 2019 and 2020

 

Reply: We had the temperature data for Kaifeng experimental station for 2018-2019 and 2019-2020, and we compared the average temperature of two winters (2018.12-2019.2 and 2019.12-2020.2) and found that the average temperature of winter in 2019-2020 was significantly higher than that of winter in 2018-2019, which is consistent with our results.

High temperature(℃)	2018-2019	6.278±0.424	F1,179=15.61	Sig.=0.000112
	2019-2020	8.725±0.452
Low temperature(℃)	2018-2019	-1.711±0.333	F1,179=21.668	Sig.=0.000006
	2019-2020	-0.253±0.260

 

 

Unexpectedly, more aphid population was observed in the disease-susceptible varieties than the other varieties. reviewer - please explain "unexpectedly.

 

Reply: This sentence was closely related to the following sentence. The previous study showed that cultivar mixtures might be endowed with additional superior attributes and offered a notable yield advantage over susceptible cultivars. In this study, the cultivar mixtures and resistant treatment both significantly reduce the occurrence of pests compared with the susceptible treatment, the cultivar mixtures did not increase the yield compared with the susceptible treatment in statistical significance, and the yield of the resistant treatment was lower than that of the susceptible treatment. So we use “unexpectedly” to express the results did not reach the original research assumption. “Unexpectedly, more aphid populations were observed in the disease-susceptible varieties than the other varieties; however, the susceptible wheat varieties had a high yield;” was a change to the sentence “Unexpectedly, more aphid populations were observed in the disease-susceptible varieties than the other varieties while the susceptible wheat varieties had a relativity high yield;”.

 

Conclusions:

 

Are there conclusions for this research.

 

Reply: Our research has conclusions located at the last paragraph in discussions, and we added the first level title named conclusions before this paragraph.

 

Some conclusion statements are stated in the abstract as follows " The results showed that cultivar mixture significantly decreased aphid abundance compared with the single varieties (resistant/susceptible). Cereal aphids decreased wheat yield by 8%, while cultivar mixture increased wheat yield by 5%. Additionally, cultivar mixture had significantly higher thousand-grain weights than susceptible and resistant wheat varieties in 2019 and 2020. Cultivar mixture enhanced wheat yield by decreasing cereal aphids, indicating a bottom-up or top-down effect from genetic diversity to pest abundance. Our results indicated that appropriate cultivar mixtures could manage insect pests to some extent and stabilize crop yield". reviewer suggestion: Explain in results 5 and 8 percent values from abstract and make conclusions.

 

Reply: Considering the reviewer’s suggestion, we think we had not expressed clearly in the full manuscript, so we deleted the sentence “Cereal aphids decreased wheat yield by 8%, while cultivar mixture increased wheat yield by 5%.” and added the sentence “Cultivar mixture had higher yield compared with the single varieties (resistant/susceptible)”.

 

 

 

 

Author Response File: Author Response.docx