Exploiting wheat response to blackgrass at small scale to predict tolerance in the field - a platform for plant breeders and agronomists

Lead Research Organisation: University of Cambridge
Department Name: Plant Sciences


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Swarbreck SM (2019) A Roadmap for Lowering Crop Nitrogen Requirement. in Trends in plant science

Description Summary. What was done? How was the IAA money spent?

High nitrogen (N) availability is necessary to achieve high wheat yield, and produce grains with protein content necessary for bread-making. However, N application is costly to farmers and can also cause negative environmental issues: N can leach into the environment, and release greenhouses gas in the form of N2O. Wheat varieties that are developed for the UK market are grown under high levels of N, and are not tested under lower N conditions. In France, the variety testing system has recently introduced additional testing at low N to determine the sustainability of variety performance. This has driven a strong agenda to reduce the N requirement of varieties which may impact on future practice for UK breeders. The objectives of our pump-prime project were:
Objective 1: To disseminate information from our current project to breeders and identify potential commercial partners for future collaborative projects using the germplasm and testing system developed.
Objective 2: Evaluate our small-scale N response experimental system
Objective 3: Support additional testing of carbon (C) isotopic signature as indicator for N use efficiency (NUE) to be used as a marker for N response as well as water use in breeding programs.

Activity 1: We organised a breeders' visit to our opti-plot field trials, where 52 wheat varieties and pre-breeding germplasms of wheat and triticales were grown under 6 levels of nitrogen (0, 70, 140, 210, 280, 350 kg N/ha). We invited wheat breeders from major breeding companies operating in the UK including Limagrain, DSV, RAGT, and KWS. In total four breeders joined us on the day (see photos). We explained the principles underlying the optiplots field trials, and our efforts in developing small scales experiments. We also obtained some aerial photographs of our experimental plots, which can become useful for future grant application.

Activity 2: Funds from the IAA were used to support a summer interns in the Department of Plant Sciences and at NIAB. Students in the Department of Plant Sciences participated in the last samples collection from the field, when plants had reached maturity and just before harvest. They also processed the samples that were collected at earlier developmental stages from the field and also from our small-scale experiments conducted under controlled conditions. The sample preparation implicated separating different parts of the wheat tillers (i.e. the peduncle, flag leaf, ear, kernel, lemma/palea/glumes), weighing, grinding and preparing samples for isotopic analysis. Students were also involved in measuring the leaf area of previously collected leaf images (using an ImageJ based method), calculating specific leaf area (SLA, i.e. leaf area per unit of dry weight) and conducting data analysis. They fully participated in the lab activities and attended lab meetings. Students at NIAB were involved in preparing wheat seeds from additional varieties to be tested. We had previously observed a positive correlation between the abundance of the natural 13C isotope in wheat grains and nitrogen use efficiency.
Outcomes and Impact. What was achieved? How has this helped you/the company/other stakeholders?
Additional data were generated that will become useful in writing papers.

Obj. 1: Through the breeders' visit we disseminated information about our current experiments, gained a better understanding of the specific traits that breeders select for. Interestingly, breeders expressed a lack of current incentive to select for varieties that have low N requirement at early stage of the selection process, and rather focusing on later stages. This is driven by the lack of specific N requirement information on the AHDB issued recommended list. Nevertheless, breeders provided some useful information on the possibility of providing information to farmers regarding the N requirement at later stage. Through the breeders' visit, we established strong links with breeders and have also discussed the possibilities of applying for further funding.

Obj. 2: Evaluate our small-scale N response experimental system
Plants grown under controlled conditions and on a 1:1 mixture of sand and terragreen supplemented with modified Hoagland solution providing field equivalent N levels of 70, 140, 210 and 280 kg N. ha-1, were analysed. Data measured included tiller number, yield, day to flower and grain nitrogen content. Overall, there was a good correlation between nitrogen use efficiency (i.e. grain weight produced per unit of nitrogen supplied) measured in pot-grown plants compared to those grown in the field.

Obj. 3: Support additional testing of carbon (C) isotopic signature as indicator for N use efficiency (NUE) to be used as a marker for N response as well as water use in breeding programs.
There were significant differences in flag leaf ?13C amongst varieties and as expected, there was a significant effect of N availability on flag leaf ?13C. Interestingly, we could note a decrease in flag leaf ?13C under higher N level, whereas we had previously noted an increased in grain ?13C under high N level. Flag leaf level ?13C is an integrative measure that is a good indicator of water use efficiency as it links to stomatal conductance, but it is also affected by mesophyll conductance, which links to the leaf structure and rubisco capacity. Interestingly, they were significant differences in SLA amongst varieties tested at anthesis and the flag leaf ?13C tended to negatively correlate with SLA. Overall, our data suggest that investigating the link between leaf or grain ?13C is valuable and may provide some further information on the nitrogen partitioning and use in wheat plants grown under different N levels.
Exploitation Route The findings from IP Pragmatics were summarised into a report that was included in a Follow-on Funding application that has now been submitted to BBRSC.
Sectors Agriculture, Food and Drink,Environment

Description Weed infestation is major issue threatening crop production in the UK, yield can be decreased by as much as 45% in the absence of herbicides application. Cultural methods such as tilling and application of a selection of herbicides have kept weed infestation under check. However, current practices are not sustainable as herbicides applications are costly to the farmers and can have negative environmental effects. These have already lead to environmental agencies to ban the use of some of these compounds. In addition, many weeds are developing resistance to herbicides and very few new compounds are coming to the market. New solutions, that are compatible with sustainable crop production, are needed to ensure that crop yields are protected from weed infestation. Selecting crop varieties that are more tolerant to the presence of weeds or that can suppress weed growth may provide a partial solution. We have developed a phenotypic system that provide information on crop response to the presence of weeds. However, it was difficult to know whether there would be broad interest in this approach in the agritech industry. As part of the pathfinder entitled 'Exploiting wheat response to blackgrass at small scale to predict tolerance in the field - a platform for plant breeders and agronomists', IP Pragmatics conducted a survey of the IP landscape concerning the selection of crops for tolerance and suppression of weed, including a thorough patent search. They also performed a market assessment for the technology in the plant breeding and broader agritech sector. Through their investigation and discussion with key members of the agritech industry, they have identified potential collaborators for the future development of our idea. IP Pragmatics have also advised us on the feasibility and most appropriate route to commercialisation. The findings from IP Pragmatics were summarised into a report that was included in a Follow-on Funding application that has now been submitted to BBRSC.
Sector Agriculture, Food and Drink,Environment
Description BBSRC Impact Acceleration Account (RG96069)- Stephanie Swarbreck
Amount £11,525 (GBP)
Funding ID RG96069 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 07/2018 
End 10/2018
Description Farmers visit to our field trials 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact We organised an information day and visit to our opti-plot field trials that attracted breeders. Representatives of the major breeding companies in the UK (which also have large part of the wheat breeding market in France) visited and this was an opportunities for us to discuss their challenges and also present our approach.
Year(s) Of Engagement Activity 2018
Description Presentation by Stephanie Swarbreck at for Monogram 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Presentation title:
'Defining optimal nitrogen use in wheat under a range of nitrogen levels'. The Monogram Network consists of UK based researchers with an active interest in small grain cereal and grass (including the C4 energy grasses) research. Commercial scientists and plant breeders are active members and provide the link between Monogram science and commercial exploitation. Monogram includes both basic and more applied research and its members span disciplines including plant genetics, physiology, pathology, breeding, and bioinformatics. We also have extensive expertise in outreach activities and links with industry.
Year(s) Of Engagement Activity 2018