Selecting genes for function: Exploiting genetic diversity in grasses to manage the biophysical interactions in grassland soils

Lead Research Organisation: Institute of Biological, Environmental and Rural Sciences
Department Name: Soil Environmental and Ecological Sci


Grassland is an important land use in the UK, accounting for 35% of all land cover and more than 70% of farmed land. Grassland utility is becoming more multifunctional with an increasing need to consider the pivotal role of grassland management in river basin corridors and their role in rainfall-runoff processes, which have a significant influence on flooding. The ability of vegetation to increase macro-porosity and to influence soil hydraulic properties has been recently observed. However, little is known about how grassland management influences soil profile hydraulic properties and larger scale rainfall-runoff processes. Not only should grasslands be freely draining in wet periods, but sustainable grasses need to be able to extract water stored in deep layers during dry summer periods. A unique collection of grasses that have a diverse set of gene x environment interactions will be used to link the genetics of deep rooting and water use efficiency with their function. The gene mapping approach used here will simultaneously identify genes for rooting traits and water-use-efficiency both in UK grass species and in other monocot crop species including the model monocot crop rice, thereby facilitating information exchange for the benefit of all concerned with monocot crop-sustainability. To realize the benefits from breeding grasses and selecting grass with genes for predetermined function it is necessary to understand the implications at the field and catchment scales. This is to say that we need to up-scale from microcosm and runoff plot experiments to the catchment scale. The variation in plant root growth within species and between grass species will be assessed to enable more accurate model predictions of the influence of grass rooting behaviour on soil hydraulic properties. This will provide a basis for active grassland management that has the potential to manipulate both productivity (i.e. through water availability), and environmental services through increased infiltration into the soil profile and decreased surface water run-off. The final objective of this project is to develop a model that integrates the new knowledge such that the outputs of the project may be generalized and used to reduce flood risk at the landscape scale.

Technical Summary

The purpose of this project is to test if the observed differences in the rooting behaviour and water use efficiency of existing and novel grass cultivars can explain 1) differences in water extraction patterns by grasses and changes in soil hydraulic properties at the plant and microcosm scales and 2) variation in the eco-hydrology of managed grasslands at the plot and small catchment scales. The project is based around three testable objectives that will provide a basic understanding of how soil-plant interactions in grasslands affect soil structure and eco-hydrology. The Lolium-Festuca complex provides a unique resource for the genetic analysis and 'dissection' of the complex traits that underpin crop sustainability. This project exploits introgression lines produced during the EU FPV project SAGES (which IGER co-ordinated) with Festuca-derived genes in Lolium cultivars with proven capabilities for enhanced water-use-efficiency, or soil-water extraction compared with standard Lolium cultivars. It further exploits the use of a unique set of IGER monosomic chromosome substitution lines where each of the 7 Festuca chromosomes in turn has replaced its Lolium chromosome homoeologue. The inclusion of the monosomic chromosome addition lines gives us complete genome coverage and opportunities to identify alternative genes for water-use-efficiency, or soil-water extraction other than those located during the SAGES project. The experimental work will occur at a range of scales. Initial root penetration studies will be conducted on grass cultivars from Lolium and Festuca species each with contrasting rooting traits and water-use-efficiency, and on introgression lines of Lolium containing different combinations of Festuca-derived genes using the wax layer method developed by the Rothamsted team. Data from these studies will be used to identify grasses to be grown in soil microcosms. Here both good root penetration and water extraction will be measured alongside changes to the soil moisture regime and structure assessed through the novel use of non-invasive geophysical techniques. Plot scale assessment of the influence of grasses characterised under the EU FPV SAGES project will be carried out on the Rowden experimental platform at IGER. Grasses to be grown in the runoff plot scale experiments will be identified with the aid of the initial wax layer screening method and prior knowledge of Dr. Humphreys (co-ordinator of EU SAGES project). In these plots we will be able to measure surface and subsurface runoff as well as root penetration and water extraction. We will investigate the use of oxygen discrimination to estimate the depth of water extraction in a UK grassland context. The experiments described will allow us to combine grass plant genetics and physiology with soil science in order to design novel grass genotypes for deep rooting, water use efficiency, increased infiltration and soil profile storage capacity to meet the challenges of climate change. Improved water extraction will be attributed to deep root penetration and improved soil water infiltration and storage in the soil will be attributed to changes in soil structure. Intraspecific differences of ecophysiological responses are large in grass species. We will assess how intra- and interspecies variation influences plant-soil hydrological functioning through model development and testing. To understand the implications for the project at the catchment and farm scale we will develop a stochastic SVAT-runoff model. Results from the plot scale studies will allow the development and testing of the SVAT-runoff model at the landscape scale using hydrological and land use data from the IGER Denbrook research catchment (48ha), enabling large scale predictions of the consequences of utilising novel grass genetic combinations to improve the hydrological functioning of grassland landscapes.


10 25 50
Description 1. SNP markers for 3 genes on Lolium-Festuca chromosome 3 associated with drought resistance and root growth traits.
Outcomes published in quality journals.

2. QTLs located on Lolium-Festuca chromosome 3 for new root growth, root profile, root growth under drought stress, root penetration and strength, root length.
Outcomes published in quality journals.

3. Heterosis effects between Lolium and Festuca alleles identified on chromosome 3, 6, and 7 for root growth under drought stress. Outcomes published in quality journals.

4. Tested a new method for measuring the water status of large numbers of leaf samples during drought experiments.
Outcomes published in quality journals.

5. L. perenne x F. pratensis cultivar for improved soil hydrology for use in flood control.
Submission to BBSRC Follow-on-Fund for further assessment.
Outcomes published in quality journals.

6. A new procedure to measure soil water repellence
We developed a new method to measure soil water repellence. It allows relatively large samples (at the core scale) to be
measured. An improved method of analysis provides data in agreement with the square-root of time dependence
predicted by the Washburn equation, while avoiding the difficulty of knowing the exact start time of the experiment. This
method has also been used by us in other projects and it is fully described in a peer reviewed paper.

7. An improved sampling recommendation for tension infiltration measurements
We have proposed a new approach to tension infiltration measurements in the field. The new method has a completely
randomised design and it provides data that is in agreement with an analytical solution for the infiltration of water under a
small negative pressure. Our method has the advantage of providing robust and physically based estimates of the mean
pore size in the capillary matrix as well as the extent of the macro pore network. The method we developed is currently
under review (by Soil Science Society of America Jounral) and may be suitable for advisors and consultants to make infield
estimates of soil structure.

8. Wax layer screening method for grass roots.
We have developed the wax layer screening method, previously used on rice, for use with grasses. This involved
optimizing the strength of the wax layer to screen grass clones. This project provided an exemplar of how this technique
can be used to identify the genetic basis for good root penetration of strong layers.
Exploitation Route 1. New Festulolium cultivar for improved soil hydrology and flood control can be assessed further in applications by researchers
2. New Report commissioned by Aberystwyth University written by Dr Alex Henshaw (University of Nottingham) Improved grassland in the UK: spatial characteristics (with a particular focus on Wales) and potential hydromorphological impacts associated with reseeding using a ryegrass/fescue hybrid
Date: 16 October 2009. Report aimed at evaluation of the commercial potential of the Festulolium cultivar.
3. Commercial development plan prepared for new Festulolium cultivar for flood control. Support obtained from Germinal Holdings Ltd for commercial development and for exploitation from Defra and the Environment Agency.
4. Isolation of gene sequence for salt stress root protein STRS1 with association to improved drought resistance.
Sectors Agriculture, Food and Drink,Education,Environment

Description A wide range of science in society activities were carried out by the PI and Co-Is, these include those that are directly related to this research and those of a more general nature: Directly related to research: Interview Prof P Haygarth in 2006 on BBC Farming Today and BBC Radio Devon about this application of this research The project was shown to the public on the Rothamsted Open Days. The work has been showcased in interactive workshops for primary school children at the annual North Wyke Science Fair. This event attracts over 500 children and helpers from approx. 17 local primary schools. The project has been featured at the North Wyke Open Days attended by over 200 local farmers and other members of the local community and to the Devon Association of Smallholders. The PI represented the project at the BBSRC 'Bioscience:Biomillions' event at HM Treasury 2nd June 2008, with associated spin off press coverage e.g. The work was presented to the Association of Independent Crop consultants, Science day in September 2008 and 2009. The project was present to the Rothamsted Research Association in HGCA workshop on the effect of soil management and climate on crop production, October 2008 The project was featured in a presentation to BBSRC's workshop on LWEC Objective C, on 9 June 2009 in London. Several (one high school and three undergraduate) students were given the opportunity to learn and experience research through this project. Over 500 undergraduate students have visited the North Wyke experimental plots established during this project. Recent spin out benefits have been determined for flooding as PI Haygarth has been invited to contribute to media and Environment Agency/Natural England consultations on the December 2015 flooding. Invited Lectures Designing grasses for more efficient water use. Dr Humphreys MW Welsh Soils Discussion Group. Our Changing Landscape. 2nd Dec 2009. Other Invited Lectures What on earth can grasses do? Dr MW Humphreys National Institute of Agricultural Botany 18th March 2008. Other Invited Lectures Precision breeding for multifunctional grasses. Dr Humphreys MW INRA, Lusignan, France 17th October 2008. Other Invited Lectures Rooting out a new role for grasses. Dr MW Humphreys, DR LB Turner University of Aberdeen 31st March 2009 Broader science in society activities C Macleod and P Haygarth lead the Defra Integrating Water and Agricultural Management coordination role and through this we have held meetings (indoors and outside) that have explored how scientific information can be better used to manage agricultural land. We have arranged sessions were we bring scientists, operational staff and policy staff at Defra to help them better understand and manage specific issues related to the impact of agricultural land management on the wide environment. C Macleod has been an invited participant at several key stakeholder events. An example of this is the recent EA/NFU Water Summit, December 2009.
First Year Of Impact 2006
Sector Agriculture, Food and Drink,Environment
Impact Types Cultural,Societal