VII International Symposium on Irrigation of Horticultural Crops – Travel 2012
FINAL REPORT to GRAPE AND WINE RESEARCH & DEVELOPMENT CORPORATION
Project Number: GWT1114 Chief Investigator: Everard Edwards
Research Organisation: CSIRO Plant Industry Date: 28th August 2012
VII International Symposium on Irrigation of Horticultural Crops – Travel 2012 GWT1114 July 2012 Everard J Edwards CSIRO Plant Industry PO Box 350 Glen Osmond SA 5064
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Contents Abstract
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Executive summary
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Background
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Project objectives and outputs
ISHS 7th International Irrigation Symposium Study tour of research institutions
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Acknowledgements
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Appendix 1: Budget reconciliation
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Abstract Everard Edwards presented a paper entitled “The role of rootstocks in grapevine water use efficiency: impacts on transpiration, stomatal control and yield efficiency” at the 7 th International Symposium on Irrigation of Horticultural crops, Geisenheim, Germany. Attending the symposium provided an excellent opportunity for the author to keep abreast of current developments in irrigation science, make/renew contacts that may facilitate future collaboration and to examine the research occurring at the Geisenheim Research Centre. In addition, the author's presence in Europe was utilised to make additional study visits to potential research collaborators in France and the UK.
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Executive Summary Dr Everard Edwards attended the 7 th ISHS International Symposium on the Irrigation of Horticultural Crops in Geisenheim, Germany, presenting a paper entitled “The role of rootstocks in grapevine water use efficiency: impacts on transpiration, stomatal control and yield efficiency”. Attendance at the symposium provided a valuable opportunity to hear about new insights in plant responses to irrigation and to renew and make new contacts that will facilitate potential future collaboration on research relevant to Australian viticulture. Key results at the symposium included: •
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The link between nocturnal sapflow and embolism repair, potentially giving a tool to understand some of the differences in drought tolerance between grapevine varieties. The linking of mechanistic models describing stomatal responses and plant hydraulics, together with their application for understanding limitations in plant water use. A warning on overconfidence in the use of remote sensing data to predict plant growth or stress, due to the wide variability in calibration data upon which such indices are based. A discussion on 'water footprinting', the upcoming ISO standard for this and potential inclusions and exclusions from that. The observation that there are inherent differences in the water use efficiency of photosynthesis between some plants and that understanding this may lead to better irrigation strategies or even improved plant breeding.
The travel included a study tour of highly relevant research institutions; the Geisenheim Research Center at which the symposium was held, the Institute of Vine and Wine Sciences at Bordeaux, France, and the Lancaster Environment Centre, UK. This provided valuable insights into the current state of play in rootstock physiology research in Europe, via Bordeaux and Lancaster, and into the new grapevine Free Air CO 2 Enrichment facility at Geisenheim, which could not have been gained from current publications.
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Background The International Society of Horticultural Science international symposiums on the irrigation of horticultural crops take place every three years are the pre-eminent conference on the use of irrigation in horticulture, covering all aspects of irrigation use, but with an emphasis on irrigation strategies, scheduling and plant physiology in particular. The 7th symposium was organized by four working groups of the ISHS, covering fruits, vegetables and grapevines. The symposium was centred on six main themes, with a particular focus on how to improve the efficiency of water resource use despite decreasing water quality. The meeting also aimed to improve the transfer of basic plant physiological and technical understanding into the practical application. The six primary themes were: • Evapotranspiration and canopy processes • Irrigation scheduling • Water quality / water re-use and salinity • Modelling and climate change • Remote sensing • Water / carbon footprint and socio-economic consequences
Figure 1: Delegates at the 7th ISHS Irrigation Symposium, held 16-10th July, 2012 at Geisenheim, Germany. The author is on the second row, right of centre (photo available at the conference website).
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Project objectives and outputs OBJECTIVES:
1. To attend the ISHS VII International Symposium on Irrigation of Horticultural Crops in Geisenheim, Germany and gain insight into current international developments in the understanding of grapevine canopy processes, evapotranspiration modelling, impacts of water quality and other aspects of irrigation science.
2. To present an oral paper describing the role of irrigation in determining the impacts of rootstock choice on scion physiology.
3. To discuss potential collaborative efforts on the impact of rising atmospheric CO2 with researchers at Geisenheim, Hans Schultz and Manfred Stoll. Further, to combine those discussions with the concurrent visit of Mark Downey from DPI Victoria to Geisenheim and discuss potential linkages between the Geisenheim FACE experiment and a proposed project to utilise the OTC system established at Irymple for elevated CO2 studies.
4. To meet with key researchers involved in research on rootstock:scion interactions: Nathalie Ollat at INRA Bordeaux, France, and Ian Dodd at the University of Lancaster, UK.
PLANNED PROJECT OUTPUTS:
Output
Performance Targets
Date
Attend symposium, deliver presentation on the 1. Attend VIIth Irrigation Symposium and deliver oral role of irrigation in rootstock effects on scion presentation. physiology, and actively participate in the VIIth Irrigation Symposium Scientific Committee.
20/7/2012
2. Discuss potential Meet with both Nathalie and Ian and explore collaborative research efforts ways by which GWRDC funded research could with Nathalie Ollat and Ian benefit from international collaboration on Dodd rootstock:scion interactions, with a focus on water use efficiency.
27/7/2012
3. GWRDC Travel report
28/8/2012
Report submitted to GWRDC
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ISHS 7th International Irrigation Symposium The symposium took place over five days from July 16 th to July 20th at the Geisenheim Research Centre in Germany. There were over 50 international speakers in five themes: • • • • •
water/carbon footprint and socio economic consequences, evapotranspiration and canopy processes, remote sensing, irrigation scheduling modelling and climate change.
Oral presentations were supplemented with 70 poster presentations at a dedicated poster session. Talks of particular interest included: “Minimising the carbon and water footprints of food products for multiple benefits” by Brent Clothier et al. of Plant & Food Research (New Zealand), who described how a 'water footprint' of horticultural products could be calculated in the same way as the now well known carbon footprint. Brent displayed figures for water footprints, but then argued that when calculating these for crops irrigated with water from aquifers, the recharge of ground water via rainfall should be subtracted from the calculation. Consequently for agricultural regions where aquifers were fully recharged each year, irrigation would have no impact on the water footprint of the product. The discussion is important because the ISO are shortly to finalise on a method for calculating water footprints. “Comparing water use efficiency of apples and grapes – physiological and morphological aspects” by Alan Lakso et al. of Cornell University (USA) who described inherent differences in instantaneous WUE of the two crops. This was based on curves that relate photosynthesis to stomtal conductance, with apple having a greater carbon gain per unit of water loss than grapevines, but the same maximum rate of photosynthesis. It was suggested that this was due to stomata being better coupled to photosynthesis in apple than grapevines. The results are especially relevant to the ongoing discussion about the differences between isohydric and anisohydric grapevine varieties and an improved mechanistic understanding could lead to improved breeding targets. “Remote sensing of plant stresses and use in crop management” by Lyn Jones of Dundee University (UK). Lynn gave an informative overview of current understanding in the use of thermal sensing and remote sensing indices for monitoring plant stress and growth, including the theory behind their applicability. However, he also strongly noted that the very large variation in correlations between remote sensing indices and plant parameters such as LAI (often 2-3 fold) was often ignored when indices were used to estimate those parameters and that the effectiveness of such indices can, consequently, be somewhat overstated. “Steps towards an improvement in mechanistic based models of water use by fruit trees: a case study in olive” by Antonio Díaz-Espejo, of Instituto de Recursos (Spain), who described a plant model for water use. The model was plant based and mechanistic, rather 5
than using empirical parameters (such as Etc). It combined the mechanistic stomatal model of Tom Buckley and the plant hydraulic model of Sperry; testing was carried out using an olive orchard and used to demonstrate that for trees with a shallow root system the limitation to transpiration was rhizosphere hydraulics, but that different irrigation treatments drove water use via 'leaf turgor' rather than hydraulic conductivity. Such a model could prove effective in separating out effects such as rootstock x irrigation interactions in grapevine trials. “Formation and repair of xylem embolisms: current state of knowledge and implications for irrigation of perennial crops” by Jochen Schenk of CalState University (USA), who gave an interesting talk that described how xylem recover following embolism formation. Such repair requires conduit-associated cells, but he also postulated that nocturnal sap-flow was required, noting that in all the species they had examined that are able to repair embolisms, including grapevines, nocturnal sapflow occurred. This would suggest that grapevine scions with different rates of nocturnal sapflow may also have differences in their ability to recover from xylem embolism and consequently, may be a factor in drought tolerance. The author gave a presentation titled “The role of rootstocks in grapevine water use efficiency: impacts on transpiration, stomatal control and yield efficiency” on the second day of the symposium. This appeared to be well received, with a number of individual discussions also being held with other delegates after the session as a result. The third day of the symposium was devoted to study trips. Trips with fruit, vegetable or viticulture themes were available. The viticulture tour was a trip to the Frankonia region to visit irrigation schemes and local wineries. Irrigation is currently only rarely used for viticulture in Germany as rainfall is normally adequate. However, with increasing awareness of climate change, schemes are now being considered for supplementary irrigation. The tour started in a co-operative vineyard at Sommerach, where the land is held by many different growers in parcels as small as a few square meters (Figure 2).
Figure 2: Daniel Hessdörfer describing irrigation research studies in the Frankonia region. 6
Particularly interesting was a nearby scheme where poor quality water was intercepted in a water catchment area to prevent it entering the drinking water supply and then utilised for vineyard irrigation (Figure 3). The pump house was a very impressive building compared to those used for similar sized schemes (30 ha) in Australia and had been paid for by the local water authority.
Figure 3: ISHS delegates learning about a novel irrigation scheme in Frankonia, Germany. The tour also included a visit to the Winzerkeller winery where the fruit from the many local growers was used. Due to the nature of the small landholdings and different requirements of the growers in terms of winestyle, hundreds of ferments are made each vintage, requiring many small fermenters (Figure 4).
Figure 4: The small lot winemaking facilities at the Winzerkeller in Sommerach. 7
The tour finished in Würzburg, with a visit to the well known Würzburg Prince Bishop Resicence. The Staatlicher Hofkeller Würzburg cellars beneath the residence is owned by the Bavarian state and the delegates were treated to tastings of Silvana and Riesling wines as well as an interesting talk on the local wine industry (Figure 5).
Figure 5: Extolling the virtues of the traditional style of Silvana wine at the cellars below the Würzburg Residence.
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Study tour of research institutions Geisenheim Research Center, Germany The research center (GRC) is located within the town of Geisenheim itself, which is on the north bank of the Rhine, within the Rheingau wine region. The Rheingau is one of the smaller German wine producing regions, accounting for 3% of vineyard area, but produces a large number of quality wines. The local plantings consist largely of Riesling, with Pinot noir and Müller-Thurgau being the next most prevalent varieties. The research center was founded in 1872 and, as well as providing undergraduate and post-graduate education, conducts research in viticulture, horticulture, oenology and beverages (both alcoholic and non-alcoholic). Research at the GRC is organised into seven large, interdisciplinary projects: • Secondary metabolites in wine, beverages and horticultural products • Steep slope viticulture • Biotechnology • Environmental stress and sustainable production • Grape health • Precision management in the wine and horticultural sciences • Development of diagnostic and measurement tools for research
Figure 6: Winery and yard at Geisenheim Research Center Dr Manfred Stoll, acting head of department for viticulture, provided an overview of the department's research activities and a tour of the relevant field sites. Of particular interest was the Free Air CO2 Enrichment (FACE) facility, which will be used to study the impacts of elevated CO2 in viticulture on a scale not previously available anywhere in the world. The facility also uses a bespoke system of fan-blower diffusers to generate the CO 2-air mixing required, with each one of the 40 or so in the ring being individually controlled according to wind direction. Rather than having a series of CO 2 injection points at different heights the 9
diffuser blows air down towards the ground, creating a 'curtain' around the ring, with natural wind movement then moving the air across the ring, as with other FACE systems.
Figure 7: One of six FACE rings at Geisenheim, planted with Riesling vines. The viticulture component of the facility comprises of six rings, which have been planted with young Riesling vines. However, the CO2 enrichment has not yet been started, so the system is not yet operational. The facility also includes two identical rings for fruit tree, which are yet to be planted, and two rings that operate on a similar principal for vegetables and flowers. One of the latter rings is operational and currently in use. The FACE facility is being overseen by Professor Hans Schultz, director of the GRC.
Figure 8: View from within the FACE ring. Detail of diffuser pod inset. As in Australia there is an increasing interest in the use of biodynamic and organic 10
viticulture in the Rheingau and the GRC has a trial comparing biodynamic, organic and standard integrated viticultural systems. The trial is fully replicated, with each replicate having two rows for research use as well as buffer rows. The organic and biodynamic treatments are identical except for the inclusion of commercially obtained biodynamic preparations.
Figure 9: Head of viticulture, Manfred Stoll, with PhD student, Johanna Döring, examining disease prevalence on young fruit. The Rheingau is a UNESCO world heritage site, consequently there is limited scope for altering current management systems where they affect the appearance of the rows. However, the GRC is utilising a novel form of minimal pruning, where the vertical shoot position trellis is maintained, but pruning consists only of cutting back laterals, with the primary canes being left in place. This leads to many more buds than is usual and extremely high fruitfulness, with over 40% of the crop needing to be removed. However, the higher crop load allows ripening to be slowed, which is advantageous in adapting to advancing harvests as a result of climate change. Another trial aimed at slowing ripening has contrasted severe summer pruning, where the vines are pruned to the second wire down from the top of the trellis and leaf thinning above the bunch zone, where the outer leaves are removed from the upper half of the canopy. The latter maintains the appearance of the vineyard, whereas the former results in 'short' vines. A third treatment used removal of leaves in the bunch zone at fruit set.
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Figure 10: Extremely high fruit set as a result of minimal pruning in a VSP system.
Figure 11: Leaf pruning trials: severe summer pruning (left) and leaf thinning above the bunch zone (right). 12
One of the features of the Rheingau region is the very steep vineyards that are on the banks of the river. Some of these vineyards are difficult and dangerous to work in and have been unsuited to mechanisation. The GRC is trialling irrigation in these vineyards, as they have a high fraction of rainfall runoff, and new methods of mechanisation. An anchoring bar set into the terrace allows equipment, such as a small caterpillar track tractor, to be safely utilised on the slope.
Figure 12: Steep slope vineyard in the Rheingau. Anchoring mechanism for mechanised equipment inset. Institute of Vine and Wine Sciences – Bordeaux, France The Institute of Vine and Wine Sciences (Institut des Sciences de la Vigne et du Vin – ISVV – Figure 13) was created under the State-Region plan 2000-6 to provide research, higher education and technology transfer. The institute includes INRA, Bordeaux University 1 & 2 - including ENITAB – Bordeaux University 3 & 4 and Bordeaux School of Management (BEM). ISVV has a dedicated new building opened in 2010 at the INRA site in Villenave d’ Ornon (Figure X). The institute has a number of principal research topics: • Agronomic and oenological approaches for the quality of the grapes and the wines (Univ. Bordeaux 1, INRA, Univ. Bordeaux 2) • Health and integrated protection of the vine (INRA, ENITAB) • Structure and biological activities of the polyphenols (Univ. Bordeaux 2) • Sustained viticulture and the environment (Univ. Bordeaux 1, INRA, Univ. Bordeaux 2) • Management and wine economy - innovation - regulation (Univ. Bordeaux 4) • Rights and civilisations (Univ. Bordeaux 3). The 'Ecophysiology and Functional Genomics of the Vine' section, has approximately 35 permanent staff and consists of two research themes, the 'grafted plant' and 'grape quality'. The author was hosted by Dr Nathalie Ollat who heads the grafted plant theme. This theme is aimed at analysis and modelling of rootstock / scion interactions, particularly the effects of the rootstock on vine adaptation to water stress. As part of this, there is a 13
focus on rootstock conferred vigour and the genetic determinism of tolerance to water stress induced by the rootstock.
Figure 13: ISVV building at INRA Bordeaux. Much of the groups work takes a large scale genetic approach, utilising a number of rootstock/scion populations. In particular the group is using two populations, a selection of 80 rootstocks, with various origins, and 130 Riparia Gloire de Montpellier (RGM) x Cabernet Sauvignon (CS) crosses. Both are utilised in pot and field experiments. The former are grafted with Merlot at an off-site field station (Figure 14) and data on growth, phenology, yield and berry soluble sugars have been collected for a number of seasons in order to assess the extent of impact that rootstocks can have on these parameters.
Figure 14: Rootstock trial of 80 rootstocks grafted with Merlot. 14
A subset of the RGMxCS crosses is also planted into the field and grafted with Cabernet Sauvignon (Figure 15). The remaining crosses are susceptible to phylloxera and do not survive in field plantings. These crosses are being used to develop quantitative trait loci (QTL) for traits of interest, including biomass allocation and drought tolerance.
Figure 15: Field planting of Riparia Gloire de Montpellier x Cabernet Sauvignon crosses. The long-term intention of all the above work is to breed rootstocks adapted to climate change for the Bordeaux region. As part of this, research staff are working on a grafted vine model, N nutrition, graft development and trait variability. Microarray analysis is also being undertaken to locate genes that provide desirable phenotypes. Whilst visiting ISVV the author presented a 45 minute seminar title “Improving grapevine water use with rootstocks”, based on the GWRDC funded project CSP 09/01. Lancaster Environment Centre, UK The Lancaster Environment Centre (LEC) is a joint investment by the UK Natural Environment Research Council funded Centre for Ecology and Hydrology and Lancaster University. The aim behind the formation of LEC was to “address 21 st century environmental challenges, especially those related to environmental change, sustainable (water, energy) resource and chemical management, biodiversity & ecosystem function and sustainable agriculture”. Within the LEC is the Centre for Sustainable Agriculture, which has a mission to “couple cutting edge research in plant science and other disciplines with a practical focus on sustainable agriculture in order to address the ecological, economic and social challenges facing agriculture in a rapidly changing global environment”. The research theme titled 'Increasing the efficiency of water use in agriculture' is particularly relevant to Australian viticulture. It applies advances in basic plant science to improve the application of deficit irrigation, to better understand root : shoot signalling and 15
to manipulate roots to explore additional parts of the soil profile. Dr Ian Dodd is a researcher at the LEC who is a co-leader on a 13 partner pan-European project aimed at reducing the impact of abiotic stress in horticultural crops through the use of rootstocks titled: ROOTOPOWER: Empowering root-targeted strategies to minimize abiotic stress impacts on horticultural crops. This project is using a population of tomato rootstocks generated by crossing Solanum pimpinellifolium with Solanum lycopersicum to: • • •
identify genetic variation and quantitative trait loci (QTL) for the ability of tomato roots to confer crop resistance to a range of abiotic stresses, establish the physiological mechanism(s) of resistance for key QTLs, to test the stability of fruit yield QTL controlling salt resistance conferred by Solanum rootstocks.
Both the results and the methods are relevant to research on Vitis rootstocks and will include studies on rootstock conferred vigour and salt water and nitrogen stresses as well their interactions. Discussions were also held with Dr Sally Wilkinson, another researcher at the LEC who provided an update on current understanding of long-term effects of heightened ABA production (a root produced water stress signal) on long-term growth of crops. In addition, the author presented the another 45 minute seminar, with the same title and similar content to that given in Bordeaux.
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Conclusion The 7th ISHS Irrigation Symposium was a stimulating and varied collection of papers, with a significant focus on grapevines that provided a summary of current research from mechanistic science of plant water relations to highly applied studies of irrigation strategies. The symposium also provided an ideal opportunity for the author to renew and make a number of international contacts that will facilitate future collaborative efforts and act as a platform for enhancing the international profile of GWRDC funded research. The study trip resulted in a much greater awareness of research activities currently being undertaken in Europe that are particularly relevant to GWRDC funded research in Australia. This included new studies of rootstock : scion interactions and pruning techniques, the results of which are yet to be published, and will result in more efficient research in Australia as well as enhancing future collaborative work.
Acknowledgements The author would like to thank his hosts, Manfred Stoll, Nathalie Ollat and Ian Dodd, for kindly sharing their time and their research, and the GWRDC for funding the greater part of the trip.
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Appendix 1: Budget Reconcilliation This is provided separately.
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