Adaptation of Plants to Water-Limited Mediterranean-type Environments
20-24 September 2004
Factors influencing the productivity and
sustainability of agricultural systems in the Mediterranean-climatic zone of
Neil C Turner
Plant Industry, Private Bag 5,
Centre for Legumes in Mediterranean Agriculture, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
Adaptation of wheat to water limited Mediterranean type environments. The contribution of crop management
Walter K. Anderson
Abstract. Modern bread wheat has been well adapted for survival and production in water-limited environments since it was first domesticated in the Mediterranean basin at least 8,000 years ago. Adaptation to various environments has been assisted through selection and cross-breeding for traits that contribute to high and stable yield since that time. Improvements in crop management aimed at improving yield and grain quality developed more slowly but the rate of change has accelerated in recent decades.
Many studies have shown that the contribution to yield increases from improved management in the twentieth century has been about double that from breeding. Both processes have proceeded in parallel, though possibly at different rates in some periods, and positive interactions between breeding and management have been responsible for greater improvements than by either process alone.
Early emphases on water conservation through the use of bare fallow, crop nutrition through the use of artificial fertilizers, crop rotation with legumes, and mechanisation, have been replaced by, or supplemented with, extensive use of herbicides for weed management, reduced tillage, earlier sowing, retention of crop residues, and the use of ‘break’ crops for management of root diseases.
A comparison of the genetic basis of adaptation to low rainfall environments in barley
Stewart J CoventryA, Michael BaumB, Stefania GrandoB, Salvatore CeccarelliB, Haitham SayedB, Andrew BarrA, Paul EckermannC, and Jason EglintonA
Agriculture and Wine,
Barley grown in the low rainfall
environments of southern
Water and nitrogen co-limitation in Mediterranean-type agro-ecosystems
Abstract. Availability of water and nitrogen are interplaying factors restricting primary production of semiarid and arid ecosystems. Two decades ago, on the bases of economic analogies, Bloom et al. formalised a theorem stating that plant growth is maximised when all resources are equally limiting (Annual Review of Ecology and Systematics 16, 363-392). The lack of appropriate methods to quantify co-limitation has largely precluded empirical tests of the concept.
This paper discusses alternative indices of co-limitation, with emphasis on water and nitrogen, and their application to dryland faming systems. Curves relating crop production (W) and availability of resource i
(Ai) allow for the definition of an index of limitation Li as the slope of the W vs Ai curve normalised by the ratio W/A. Co-limitation between two resources a and b can thus be defined as Cab = 1 – |La -Lb|. This Cab index can be applied to a broad range of resources but has an unavoidable element of circularity in relating back to W, as they are related by definition. Modelled indices of co-limitation could largely solve this problem of lack of independence with measured crop responses, but most models only allow for few resources, i.e. water, nitrogen and radiation.
Modelled scalars quantifying the degree of water (SW) and nitrogen stress (SN) were integrated in seasonal indices to quantify the aggregated intensity of both stress (SWN = SW + SN), the degree of water and nitrogen co-limitation (CNW = 1 – |SW -SN|), and the integrated effect of stress and co-limitation (SCNW = CWA/SWN ). The expectation of grain yield being inversely proportional to stress intensity and directly proportional to degree of co-limitation was investigated using wheat yields measured in an experiment where season and rotation were the main sources of variation. Measured grain yield (range 2.5 to 4.8 t/ha) was related to SWN combining water and nitrogen stress (r = -0.66, P = 0.02), the co-limitation index CWN (r = 0.71, P = 0.01), and the SCWN index combining stress intensity and degree of co-limitation (r = 0.81, P = 0.001); SWN and CWN were unrelated (P > 0.23).
Research requirements for improved water-use efficiency
of cereal-based systems, with emphasis on
Len J. Wade and Tina Botwright
Abstract. The farming system in the south-west of
A decade of research on cool season grain legumes in dryland environments: Lessons learned
K.H.M. SiddiqueA, K.L. ReganA,B, J. BergerA, P.F. WhiteA,B, N.C. TurnerA,C and T.N. Khan A,B
for Legumes in Mediterranean Agriculture, The University of
CCSIRO Plant Industry, Private Bag 5, Wembley WA 6913
Abstract. The adaptation and yield of a range of cool
season grain legumes (chickpea, faba bean, field pea, lentil, narbon bean,
vetch and lathyrus) were studied across a wide range of dryland environments in
Lupin – the largest grain legume crop in
A Department of Agriculture, Locked Bag 4, Bentley, W 6983
Dry Land Research Institute, Department of
Abstract. Narrow-leafed lupin (NLL) (Lupinus angustifolius L.) has become the
most successful grain legume in the Western Australian with production
averaging over 800,000 tonnes per annum.
Over the last 30 years this species has been adapted to the WA
environment through exploitation of its natural abilities to grow in a
Mediterranean climate and through breeding activities. NLL is a native of the countries around the
Wild and cultivated Cicer species - different evolutionary paths lead to different phenological strategies that can be exploited to broaden the adaptation of chickpea
A Centre for Legumes in Mediterranean Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009. Email
Industry, Private Bag 5,
Abstract. In contrast to its annual, cool-season wild relatives, the chickpea (Cicer arietinum) developed as a post-rainy season, spring-sown crop early in its evolution. We suggest that these different life cycles imposed different selection pressures on the wild and cultivated Cicer species, and that as a result different phenological strategies are likely to be expressed. To test this hypothesis, diverse wild and cultivated Cicer species from a wide range of habitats were subjected to different cold treatments, and evaluated in the field. In terms of days to flowering, C. arietinum, C. yamashitae, and most C. judaicum accessions were unresponsive to vernalization, whereas the opposite was the case for C. echinospermum and C. pinnatifidum. C. bijugum and C. reticulatum were intermediate, with around 50% of accessions vernalization responsive. Since both C. echinospermum and C. reticulatum are commonly used in chickpea improvement programs this has important ramifications for breeders. The time interval between flowering and podding was significantly smaller in wild Cicer species (mean: 5-7 days) than in the cultigen (mean: 14 days), and this may be a reflection of reduced susceptibility to cold temperatures in the wild species, a trait urgently required in chickpea.
Evaluation of Helicoverpa and drought resistance in desi and kabuli chickpea
A Division of
Genetics, Indian Agricultural Research Institute, New Delhi-110012,
B CSIRO, Plant Industry, Private Bag 5, Wembley,
C Centre for Legumes in Mediterranean Agriculture, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
D Victorian Department of Primary Industries,
Differential effects of soil water deficit on plant function and their use in crop management
(Agro.M-Cirad-Inra), Cirad TA 40/01, Av. Agropolis, 34398
Abstract. Extensive studies have been conducted over the past 30 years on the effects of soil water deficit on the major functions of cultivated plants. Empirical relationships have been established between indicators of the soil water deficit experienced by the plant (for example predawn leaf water deficit or the Fraction of Transpirable Soil Water, FTSW) and the reduction of plant transpiration, net carbon exchange rate, growth of leaf area and reproductive development, in comparison with well watered plants. They have been extensively used to develop water stress modules in crop models, to compare genotypes and to justify more fundamental research on root signals and plant response to drought. Simultaneous analysis of the effect of soil dehydration (most frequently represented by FTSW) on these various functions at the various phases of the crop cycle, have been conducted in our research unit in a broad range of crops covering annuals (Pisum sativum, Cicer arietinum, Phaseolus vulgaris, Vigna unguiculata) and perennials legumes (Medicago sativa, Trifolium repens), Helianthus annuus, Gossypium hirsutum and more recently Vitis vinifera, in various conditions (from pots in the greenhouse to farmer’s fields). They consistently indicate that leaf area development is the most sensitive process to soil water deficit, with branching being more sensitive than leaf emergence and growth on the main stem. Net carbon exchange rate and the various steps of reproductive development are less sensitive to drought, thereby explaining why grain/fruit yield and or quality can be increased by a moderate drought in annuals crops, in perennial forage crops and in vineyards. In legumes, N2 fixation is more sensitive to soil water deficit than nitrate assimilation and grain yield, suggesting a strong dependency of N2 fixation to nitrogen demand by vegetative growth. Other traits of plant adaptation to drought at the crop level, such as reduction of plant cycle duration, improvement of water use efficiency, increase of harvest index (in case of early drought), and to some extend osmotic adjustment, can be explained by the observed differential effects of soil dehydration on the various plant functions. These results have been used to develop deficit irrigation strategies using tensiometers and to develop tools for in-field diagnosis of drought stress experienced by the crops, especially for seed production and grape production.
The improvement of crop yield in marginal environments using “on-farm” seed priming
Centre for Arid Zone
Abstract. On-farm seed priming with water is a low-cost, low-risk technology that is easily adopted by resource-poor farmers and which increases the yield of tropical and sub-tropical annual crops in marginal areas. Such yield increases result from a combination of better crop establishment and improved individual plant performance. The effects of seed priming on plant growth and development are consequences of faster germination, emergence and more vigorous early growth. Data from in vitro, on-station and on-farm experiments are presented and discussed. Recent work has tested opportunities for resource-poor farmers to use seed priming as a vehicle for applying biofertilisers (rhizobia), micronutrients, e.g. molybdenum, and systemic fungicides. Preliminary results suggest strongly that these interventions are not only very effective (over and above the already-demonstrated benefits of priming with water alone) but also offer significant cost savings to farmers. Lowered costs are particularly attractive to farmers in marginal areas and increase the likelihood of adoption of new technologies.
Observations in the field have shown that some primed crops show enhanced resistance to disease, either as a consequence of increased vigour, altered phenology or due to some more fundamental mechanism associated with exposure of seeds to anaerobic conditions during priming. Results from preliminary investigations to test the latter hypothesis are presented and discussed. Seed priming is a practical and effective way for resource-poor farmers to increase crop productivity. It is particularly well suited to small-scale, non-mechanised agriculture in warm climates where soil moisture at sowing is the limiting factor rather than low temperature. Nevertheless, the effectiveness of seed priming should be evaluated in similar climates in more developed countries. If it were found to be effective, adaptation of the approach to mechanised systems would be a priority.
‘On Farm’ Issues -sustainability
Peter Macleay, Claire Macleay
Abstract. This paper discusses the pressures on agriculture to be sustainable. What is agriculture supposed to sustain? Ultimately agriculture is responsible for providing the sustenance of this civilization. Is our agriculture the worst sector of this society? We cannot conclude that it is.
Economic forces have been good at producing productive innovation in the economy and have been the main driver for the success of our civilization. However, we can demonstrate that economists do not value the future highly, so we all consume ever increasing amounts of the world’s resources, with little thought of the future.
The growth in the world’s population continues, as does consumption per head. Agriculture has an admirable track record in satisfying this increase in consumption. There are challenges facing agriculture but it is the demands placed on it to continually produce more for less, and with less fresh water and arable land available. It is these pressures that are ultimately unsustainable.
Drought resistance, water-use efficiency and yield potential – are they compatible, dissonant or mutually exclusive?
Abstract. This presentation is a concept review paper dealing with a central dilemma in understanding, designing and acting upon crop plant improvement programs for drought conditions. The association between drought resistance (DR), water-use efficiency (WUE) and yield potential (YP) is often misunderstood which can lead to conceptual oversight and wrong decisions in implementing breeding programs for drought-prone environments. While high yield potential is the target of most crop breeding programs, it might not be compatible with superior drought resistance. On the other hand high yield potential can contribute to yield in moderate stress environments. Plant traits that enhance yield potential should therefore be reviewed in the context of their effect on and interaction with DR and WUE on the background of the prevalent drought profile in the target environment. Plant production in water limited environments is all too often affected by constitutive plant traits that allow maintenance of plant water status rather than by strictly stress adaptive responses that support plant function at low water status. A major adaptive response sustaining crop production under drought stress is osmotic adjustment (OA). Despite past voiced speculations, there is no proof that OA entails a cost in terms of reduced yield potential. WUE for yield is often equated in a simplistic manner with DR. The large accumulation of knowledge on crop WUE as derived from research on carbon isotope discrimination allows some conclusions to be reached on the relations between WUE on one hand and DR and YP on the other. Briefly, apparent genotypic variations in WUE are normally expressed mainly due to variations in water use (WU; the denominator). Reduced WU which is reflected in higher WUE is generally achieved by plant traits and environmental responses that reduce YP. Improved WUE on the basis of reduced WU is expressed in improved yield under water limited conditions only when there is need to balance crop water use against a limited and known soil moisture reserve. However, under most dryland situations where crops depend on unpredictable seasonal rainfall, the maximization of soil moisture use is a crucial component of drought resistance (avoidance) which is then often expressed in lower WUE. It is concluded that the effect of a single “drought adaptive” gene on crop performance in water-limited environments can be assessed only when the whole system is considered in terms of DR, WUE and YP.
Comparative eco-physiology of Cicer sp.
Roi Ben-David and Shahal Abbo
RH Smith Institute of Plant Science and Genetics in Agriculture, The Levi Eshkol School of Agriculture, The Hebrew University of Jerusalem, Rehovot 76100, Israel
Seed and pod water relations of Chickpea under wet and dry soil conditions
Ken Shackel A Hamid AhmadiA and N. C. Turner B
A Department of Pomology,
B CSIRO Plant Industry,
Abstract. Seed growth (pod filling) is a relatively drought resistant process in chickpea, and previous research has shown that the water relations of the seed coat, and hence presumably the seed as a whole, is essentially independent of the water relations of the parent plant. When plants in dry soil are irrigated, stem (covered leaf) water potential recovers quickly, with an equivalent recovery in pod water potential, as measured either by the pressure chamber, or by an increase in the turgor of cells in the outer pod wall. In contrast, the turgor of cells in the seed coat remains relatively constant and relatively low (about 0.1 MPa), despite the fact that the seed coat is vascularized, maternal tissue. The outer and inner pod wall of chickpea are separated by a zone of very tough, lignified cells however, and hence the increase in outer pod wall water potential may not indicate a similar increase in inner pod wall. Both the outer pod wall and seed coat are convex surfaces and hence can be viewed relatively easily for the purpose of measuring cell turgor with the turgor pressure probe, but the inner pod wall is concave and can not be viewed easily. Attempts were made to recurve a flap of pod wall to make the inner surface more accessible, but generally low and variable cell turgors, which did not respond well to irrigation, were measured using this technique. Using a more invasive technique involving removal of most of one half of the pod as well as the seeds, but leaving the opposite half undisturbed, we were able to document clear increases in the turgor of inner pod wall cells upon irrigation of previously dry plants. Unlike cells of the outer pod wall, inner pod wall cells were delayed in their response to irrigation, but by about 20h, the overall increase in cell turgor corresponded to the overall increase in stem water potential exhibited by the plant. Since the water status of both the inner and the outer pod walls responds to irrigation, the funiculus may represent a likely candidate zone of isolation between the pod and the seed, but the prevention of water potential equilibrium across this zone, despite maintenance of phloem transport to the seed through it, is difficult to reconcile with our current understanding of symplastic and apoplastic water flow in plants.
Can water use and yield of annual crops be increased on soils with physicochemical constraints using primer-plants?
Stephen L. DaviesA, James G. NuttallB, Roger D. ArmstrongB, Matthew H. McCallumAC, John A. KirkegaardA and Mark B. PeoplesA
B Department of Primary Industries, Private Bag 260 Horsham, Victoria 3401
C Present address: AgConsulting, Ardrossan, SA, 5571
root growth in alkaline subsoils of south-easterrn
Water and nutrient use efficiencies in different wheat genotypes
Xi-Ping Deng A, Ming-li Huang B, Yong-hui Yuan A and Shinobu InanagaC
of Soil and Water Conservation, Chinese
Optimal sowing time and seeding rate for winter-sown, rain-fed chickpea in a cool Mediterranean area
Faculty of Agricultural
and Food Sciences, American
P.O. Box 11-0236,
Genomic approaches to improve drought tolerance in cereals
Roberto Tuberosa and Silvio Salvi
of Agroenvironmental Science and Technology, Viale Fanin 44, 40127
of root growth under water deficits by
Robert E. Sharp A, In-Jeong Cho A and Mayandi Sivaguru B
A Department of
Agronomy and B Molecular Cytology Core Facility,
Abstract. Our previous
work showed that accumulation of abscisic acid (
Drought adaptation in maize, wheat and soybean: some signalling aspects
Christian R. Jensen and Fulai Liu
The Royal Veterinary and Agricultural University, Department
of Agricultural Sciences, Hoejbakkegaard
Abstract: The root
system communicates changes in soil water availability to the shoot via xylem
hydrostatic pressure and non-hydraulic (chemical composition of the xylem sap)
signals. Due to a decrease in nitrate uptake by mass flow during mild drought
stress, expansion growth of young leaves may decrease through changes in the
cell wall protein metabolism. Also reduced nitrate uptake may immediately
increase xylem pH, decreasing both the protonation of
Physiology of abscisic acid (
Julius von Sachs Institut für Biowissenschaften der Universität, Lehrstuhl Botanik I,
Julius von Sachs Platz 2, D 97082 Würzburg, Germany
Abstract. Abscisic acid (
The assimilate partitioning in non domesticated rice in a water-stressed environment
P. K .Mohapatra
Adapting woody perennial systems to water-limited Mediterranean-type environments: a phase farming approach
Richard HarperA,B, Nicole RobinsonA and Keith SmettemB,C
B CRC Plant
Based Management of Dryland Salinity,
C Centre for Water
Abstract. The salinization of land
and water resources is a major environmental problem in
Salt and drought tolerance in Eucalyptus spp.: the role of cyclitols as osmolytes
Mark AdamsA and Andrew MerchantB
ACentre of Excellence in Natural Resource Management, UWA,
How do plants respond to spatial and temporal variations in soil water limitations?
Relations between leaf d13C, tree ring growth and
precipitation of Eucalyptus along a rainfall gradient between
southwestern Australia and central
Ernst-Detlef SchulzeA, Neil C. TurnerB, Dean NicolleC
Max-Planck Institute for Biogeochemistry,
CSIRO Plant Industry, Private Bag 5,
Adaptation of olive (Olea europaea L.) to water-limited Mediterranean environments
Departamento de Agronomía, Universidad de Córdoba and Instituto de Agricultura Sostenible (CSIC), Apartado 4084, 14080 Córdoba, Spain
Drying and wetting of soils stimulates decomposition and
carbon dioxide emission: the “Birch Effect”
of Atmospheric and Environmental Science,
Abstract. Recent work on the carbon budget of forests
has revived interest in a phenomenon first characterised on agricultural soils
in the 1960s by H. F. Birch in
resistance of native and introduced perennial grasses of southeastern
T.BolgerA, A.R. RivelliA,B, and D.L. GardenC
Plant Industry, GPO
of Plant Production,
Abstract. Perennial grasses are
the key to the economic and environmental sustainability of pastures for
livestock grazing on the
The nitrogen nutrition status of grasslands under water deficits
Jean-Louis Durant, Victoria Gonzalez Dugo, François Gastal
Unité d'Ecophysiologie des Plantes Fourragères, INRA, 86 600 Lusignan, France. firstname.lastname@example.org
Abstract. Grasslands rarely
are irrigated. They are therefore systematically submitted to more or less
severe water deficits. Among other mineral deficiencies, water scarcity most
often also induces a reduction of the plant nitrogen nutrition status. This
further reduces forage production both quantitatively and qualitatively, and it
alters the N cycling in grasslands. Although identified for long,
qualitatively, the interaction with nitrogen still remains difficult to take
into account in a quantitative analysis of the crop physiology under water
deficits. The paper first illustrates how the nitrogen status of the crop
changes under water deficits. A nitrogen nutrition index (
Simulating water stress responses in crop phenology models
Gregory S. McMaster
USDA-ARS, Great Plains Systems Research Unit, 2150 Centre Ave., Bldg. D, Suite 200, Fort Collins, Colorado, U.S.A.
Abstract. Understanding and predicting crop phenology is fundamental to crop management. While temperature is usually the critical environmental factor driving phenology, other factors (particularly water) can play a secondary role. Quantifying water stress responses has received less attention than temperature. This paper describes the status of a model for predicting crop phenology (Phenology MMS) that can be used independently or incorporated into existing crop growth models. This new model synthesizes and quantifies the entire developmental sequence of the shoot apex of many crops, making this information readily available to users with limited knowledge of phenology or the crop of interest.
A Java-based interface allows the user to interact with the underlying Fortran simulation model. Developmental sequences are quantified using thermal time (either growing degree-days or number of leaves. The user chooses default values for a cultivar or changes the values as desired. Stress responses are most simply incorporated by selecting for either optimal or stressed conditions that changes the thermal time estimates appropriately. Greater refinement of thermal estimates is possible when more information is available. It is also important to understand the effects of specific stresses on specific growth stages or developmental processes. Based on previous research, wheat and barley phenological responses have been quantified where water stress prior to jointing has little effect, and the effect increases progressively for later growth stages reaching a maximum for grain filling duration. For maize, a critical effect of water stress is on increasing the anthesis-silking thermal time interval.
Environmental and genetic control of morphogenesis in crops: towards models simulating phenotypic plasticity
Michael DingkuhnA D LuquetA, B QuilotB
A CIRAD/AMIS/Ecotrop, Avenue Agropolis, Lavalette, 34398 Montpellier, France
B INRA Avignon, Unité de recherche Plantes et systèmes de culture horticoles, Montfavet, France
Abstract. As molecular biologists are realising the importance of physiology in understanding functional genomics of quantitative traits, such as those related to agronomic characters; and as physiologists are realising the formidable prospects for improving their phenotypic models with information on the underlying gene networks, researchers worldwide are working on linked physiological-genetic models. These efforts are in their early methodological stage despite/because of the availability of many different types of models, the problem being to bring together vastly different ways scientists see the plant. This paper describes exemplarily some current efforts to adapt phenotype models to the objective of simulating gene-phene processes at the plant or crop scale. Particular emphasis is given to the models’ capacity to simulate genotype x environment interaction and the resulting phenotypic plasticity, assuming that this permits defining model parameters that are closer to specific gene action. Three different types of approaches are presented: (1) a generic, mathematical-architectural model called GREENLAB that simulates resource modulated morphogenesis, (2) an ecophysiological model of peach tree fruit development and filling, parameterised for a mapping population to evaluate the potential of plugging QTL effects into the model, and (3) a new modelling concept that aims at constructing the plant and its phenotypic plasticity from meristem behaviour, with the principal hypothesis being that resource limitations and stresses feed back on the meristems. This latter choice is based on the fact that gene expression happens to a large extent in the meristems. The different modelling concepts are critically discussed with respect to their ability to simulate phenotypic plasticity and to operate with parameters that approximate specific gene action, particularly in the area of morphogenesis.
Policy issues impacting on crop production in water limiting environments
John C Radcliffe
CSIRO, Private Bag 2, Glen Osmond SA 5064
beginning of the 20th century when
The Australian Federal Government has responsibilities under its external powers for any issues of an international nature. However, the development of international treaties and agreements covering such issues as Biological Diversity, Conservation of Natural and Cultural Heritage, Migratory Routes for Birds, Conservation of Plant Genetic Resources, UNCED (Agenda 21), the Kyoto Declaration, the Convention on Persistent Organic Pollutants, together with membership of the World Trade Organisation, International Trade Agreements, maintenance of national security and the Trade Practices Act have all brought the Commonwealth closer to natural resource management and production issues at farm level.
The States have introduced additional, sometimes complementary regulations and guidelines covering many specific issues such as conservation of native vegetation, water resources, management of pests and diseases, waste management and pollution control for use of land, water and the atmosphere, occupational health and safety, and food quality. Markets are increasingly setting more specific purchasing standards outside of formal government frameworks, and constitute a further form of de facto regulation.
How these regulations, guidelines and standards have been developed and imposed is outlined.
Grower investigations to improve the viability
of risk-prone crops in low rainfall environments of the central wheatbelt of
Jeff RussellA and Angie RoeB
ACentre for Cropping Systems, Department of Agriculture, Western Australia, 12 York Road, Northam, Western Australia 6401
BFarm Focus Consultants,
Abstract. Lupin and canola crops are recognised by
growers in the low rainfall central wheatbelt of
Crop orientation has currently become of interest to the growers with the recent developments being generated through ‘Tramline’ technology systems. Crop architecture as impacted by seeding rate and row spacing may influence crop performance. The concern here is if row orientation influences crop performance as this will have a bearing in the direction of establishing tramlines. This needs consideration when a grower is planning long term farming system changes.
The results of a number of on farm research (OFR) activities conducted by members of the group in 2001 to 2003 are outlined to show how growers are best tackling the issue of reducing total crop failure in lupins and canola. These investigations are showing that where lupin yield potential is low, as in this environment, wider than normal row spacings employed at seeding are improving yields. The reverse is indicated with canola. Likewise in an environment of lower yield potential, growers are refining current small scale research developments through OFR to determine the optimum seeding rate of these crops. Results are indicating adopting lower seeding rates than those determined through the intensive research studies of agronomists. Row orientation in lupins is less conclusive in its findings through similar OFR activities and there is the indication that this may be influenced by crop yield potential. Decision support systems for growers are then being developed from the outcomes of the OFR carried out by group members.
Mohammad Amjad A, Ben CurtisB and Wal K AndersonC
A, B Western Australian Department of
C Western Australian Department of
Abstract. South coast growers are
faced with a choice of new wheat varieties both from WA and the eastern states,
about which there is often little relevant information available in the local
environment. Agronomic investigations were carried out to identify new wheat
varieties suitable for the Esperance port zone to improve yield, grain quality
and local adaptation on the costal sandplain (average annual rainfall 490 mm
and May-October rainfall 342 mm) and inland Mallee (average annual rainfall 342
mm and May-October rainfall 209 mm). A total of 31 wheat varieties were tested
in both small-scale agronomy trials and large-scale farmers’ trials. A good
start to the 2003 season followed by consistently good conditions around grain
filling has generally resulted in higher grain yield averaging over 3.0 and 4.0
t/ha in the mallee and sandplain environments, respectively. May sowing on the
opening rains in the Mallee resulted in 40 % greater yield than the late June
sowing. On the sandplain the May sowing (in marginal conditions) yielded
similar to late June sowing (3.5 t/ha), and the early June sowing out-yielded
both May and late June sowing by 0.5 t/ha. Differences between varieties in
response to increasing seed rate that were evident at 30kg/ha of applied N were
much less evident at 60kg/ha of N. All varieties responded positively to the
combination of high seed rate (200 plants/m2) and 60 kg/ha of N. Foliar disease
resistance (leaf, stem and stripe rusts, and Septorias) and grain quality
problems (including staining, sprouting, low falling numbers and mouldy grain)
are still a great concern in the adaptation of new wheat varieties in the
Esperance port zone. High yield potential and high grain quality attributes are
the key parameters in variety selection on the coast. Based on the results of
2003 and field experience there appears to be a trade-off between yield,
disease resistance and susceptibility to weather damage. The highest yielders
have been Wyalkatchem and H45 in 2003. Wyalkatchem has broken down to stem rust
and looks risky for the Esperance region.
H45 is susceptible to stripe rust and requires special management. Based
on limited testing in 2003 GBA Sapphire, WAWHT2524 and WAWHT2661 have also
shown promise. The best tolerance to weather damage is probably found in Sun
types (Braewood) and Cook/Sunelg type (WAWHT25252A), and the disease situation
is best addressed with Janz and it’s derivatives (Annuello, Mitre and Babbler).
The key consideration appears to be choosing the appropriate mix of varieties
depending on the risk factors, yield, and likely sowing times. A cropping
program based on one, or a limited number of varieties, is less likely to
succeed in the long term. Growing two or more varieties with different
maturity, better disease resistance, tolerance to weather damage and grain
quality characteristics should help to reduce risks in the south coast
Responses of tomato to reduced irrigation
M. Hossein Behboudian, Lai F. Ow and Jorge A. Zegbe -Dominguez
Institute of Natural Resources, College of Sciences, Massey University, Palmerston North, New Zealand
Abstract. Water supplies are limited worldwide and therefore there is a need to adopt water-saving irrigation practices. In a glasshouse study we compared deficit irrigation (DI) with partial rootzone drying (PRD) for their effects on ‘Petopride’ processing tomato (Lycopersicon esculentum Mill.). The treatments were: full watering on both sides of the root system considered as control (C), half of the irrigation water used in C applied to both sides of the root system at each irrigation (DI), and half of the irrigation water in C applied to only one side of the root system at each irrigation (PRD). Photosynthetic rate, transpiration rate, stomatal conductance, and leaf water potential, measured on five occasions, were lower for DI and PRD than for C. Total fruit dry and fresh mass per plant as well as harvest index was reduced in DI and PRD. Irrigation use efficiency was higher and fruit water content was lower in DI and PRD than in C. Fruit size, in terms of fresh mass, was the same for the three treatments. On a percentage basis, less dry matter in the plant was allocated to DI and PRD fruit than to C fruit. Tomato fruit, which is normally a stronger sink than vegetative parts, becomes a weaker sink during water stress. Quality was enhanced in terms of higher concentrations of sucrose, glucose and fructose in DI and PRD fruit than in C fruit. DI and PRD fruit also showed advanced ripening judged by higher production of ethylene and CO2. The earlier ripening of DI and PRD fruit was further supported by the rapid development of red colour. DI and PRD had a higher incidence of blossom end rot than did C. Differences in growth and yield were not significant between DI and PRD. Growers who are presently using DI should find little benefit in switching to PRD, as the implementation of PRD is time consuming and installation costs higher. However, water was saved by 50% in both DI and PRD treatments and their adoption may be economically feasible in regions where water shortage could limit the production of tomatoes.
Maize (Zea mays L.) and sorghum (Sorghum bicolour L.
Moench) response to water deficit in a Mediterranean environment
A Department of Agriculture, Locked Bag 4
B Unidad de Suelos y Riegos, Centro de Investigación y Tecnología Agroalimentaria de Aragón, Apdo 727, 50080 Zaragoza, Spain
Abstract. Growing more drought
tolerant crops can save water in regions where irrigation water is limited.
Field experiments were conducted during two growing seasons on a loam soil
(Typic Xerofluvent) to compare the responses of maize (Zea mays L.) and sorghum (Sorghum
bicolor L. Moench) to deficit irrigation. Soil water status, crop
development, yield and yield components were measured in a sprinkler
line-source experiment. Seasonal evapotranspiration, crop growth, total
above-ground biomass and yield were markedly affected by the irrigation
treatments in both crops. Growth and yield were less in 1994 than in 1995, due
to additional salt stress in 1994. Maize was superior to sorghum under well
irrigated conditions, but sorghum outyielded maize under moderate or severe
water deficits. In both crops yield was reduced through the reduction in the
number of seeds per m-2 and seed weight. Sorghum had a greater
ability to extract soil water from deeper soil and its higher yield under
deficit irrigation was achieved by a higher above-ground biomass and a higher
HI. Biomass and yield were linearly related to ET in both crops, with absolute
greater slopes in maize. The two crops did not differ in WUE but sorghum
appeared more efficient in the use of supplemental irrigation water under
drought. The results show that sorghum could be an alternative crop to maize
under limited water supply in the semi-arid conditions of northeast
Drought resistance in wild emmer wheat, a potential for wheat improvement
Y. SarangaA, Z. PelegA, S. AbboA, T. KrugmanB, E. NevoB, D. YakirC and T. FahimaB
AThe Robert H. Smith Institute of Plant Science and Genetics in Agriculture,
BInstitute of Evolution,
CDepartment of Environmental Sciences and Energy Research, Weizmann Institute of Science, P.O. Box 26, Rehovot 76100, Israel
Abstract. Wild emmer wheat (Triticum turgidum spp. dicoccoides
(Körn.) Thell.), the tetraploid progenitor of cultivated wheat, is a
potential source for many valuable agronomic traits. The genetic diversity for drought resistance
in wild emmer wheat and its relationship with the ecogeographical parameters of
the wild emmer's collection site were studied.
A collection of 110 wild emmer accessions consisting of 25 populations
Wide genetic diversity was found both between and within the wild emmer populations in most variables under each treatment. A considerable number of the wild emmer accessions exhibited greater total dry matter and spike dry matter under both treatments and smaller susceptibility to drought stress, as compared with their cultivated counterparts. Most wild emmer wheat accessions exhibited a greater carbon isotope ratio (δ13C, indicating higher water use efficiency) under the dry treatment and higher plasticity of δ13C (greater improvement in response to stress) relative to the cultivated controls, which may have contributed to the drought adaptation of the former. These results suggest that wild emmer wheat may offer the potential to improve drought resistance of cultivated wheat. The most outstanding drought resistance capacity was detected in wild emmer populations from hot, dry locations, directing further exploration to these ecosystems.
Quantitative relationship between grain and whole plant dry-matter increase during the grain-filling period in wheat subjected to postanthesis water deficit
Tohru Kobata and Kei Kunimasa
Faculty of Life and Environmental Science,
Abstract. Wheat crops grown in Mediterranean climatic regions often suffer terminal water stress during the grain filling period. Consequently, quantitative analysis of the effect of postanthesis water deficit on grain production may be significant in overcoming or diminishing yield reduction. A theoretical expression of grain growth based on dry matter analysis has been proposed to describe the effects of dry soils and shading during the grain filling period (GFP) of rice. This expression predicts grain dry-matter increase (G) as a function of the total shoot dry-matter increase (W) during the GFP, and is based on two parameters: potential G, and the quantity of potentially mobilized reserves in the stem. Spring wheat (Norin 61) was grown in pots under several soil moisture regimes during the GFP. Both W and G decreased with the strength of soil drying. A proportion of the severe desiccated plants were rehydrated after early GFP. The relationship between G and W was indicated by two trends: G equalled potential G when the total assimilate supply (the amount of potentially mobile reserves in the stem plus the W) was equal to, or greater than the potential G. Below that level of assimilate supply, G decreased in proportion to W during the GFP. The G of the rehydrated plants almost reached that of well-irrigated control plants. Hence we conclude that the model concept established in rice is equally applicable to wheat subjected to postanthesis water deficit during the GFP. This model can also be used as a sub-model to estimate the impact on wheat grain production of water deficit during GFP.
of Agricultural and food Sciences, American
Abstract. In dry areas, crops are prone to be affected by boron (B) toxicity caused by high soil B levels. In most of the studies on B toxicity in pots, excess B was introduced right from germination. Growing plants in soils uniformly mixed with B could have exaggerated the effects of B toxicity in the field, where high B levels usually occur in subsoils. The objective of this experiment was to study the effects of different patterns and timings of B supply on the development, growth, and yield of barley. The pot experiment was conducted in a plastic house. Each pot consisted of two sections of 20-cm tall PVC pipe. At a specific time, the second section was watered to field capacity and joined to the bottom of the top section. A three-factor factorial design that consisted of three patterns of B supply, three timings of B supply, and two barley lines was used with two replicates. A barley line from the cross Arar/Arabic Aswad (abbreviated as AA) and the variety ‘Harmal’ were compared. The former had less severe foliage B-toxicity symptoms than the latter in previous year's seedling test. The three patterns of B supply were: no B added (-/-), B added to the bottom section only (-/+), and B added to both sections (+/+). The addition of 50 mg B/kg soil increased the hot-water soluble B level from 0.7 to 21 p.p.m. The sections were joined on 25 Jan (tillering; roots reached the bottom of top section), 15 Feb (elongation), and 20 Mar (flag leaf emerged for Harmal; booting stage for AA). There were highly significant differences in grain yield between the three patterns of B supply [(-/-) > (-/+) >> (+/+)]. Delay in adding the second section decreased yield, but there was no interaction between the two factors. Compared to the -/- treatment, Harmal had a significant yield reduction under the -/+ treatment, but there was no yield reduction for AA. The yield difference between the two lines decreased in the +/+ treatment. Three conclusions can be drawn from the results of this study. First, subjecting plants to high B soils from germination to maturity exaggerates the effects of B on rain-fed crops in the fields. Second, high subsoil boron levels can cause yield reduction even when roots reach it as late as the boot stage. Third, the screening of seedling for severity of B-toxicity symptoms at high B levels is able to differentiate the yield responses of genotypes to high sub-soil B level.
Response to water deficits of lentil genotypes from
R Shrestha A, B, Neil C. Turner A, C, David
A Centre for Legumes in Mediterranean Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009
C CSIRO Plant Industry, Private Bag 5,
Abstract. Lentil (Lens
culinaris M.) is the major legume crop in
S.S. YadavA, F. MuhelbauerB, Neil C. TurnerC, Bob ReddenD, P.N. BahlE, and J. KumarA
ADivision of Genetics, Indian Agricultural
Research Institute, New Delhi-12,
CCSIRO Plant Industry, Private Bag 5,
DATFCC, Agriculture Victoria,
EFAO, Grain Legumes Lead Consultant,
Abstract. Present investigations were taken up to formulate the selection strategies for screening the segregating populations and to identify drought tolerant chickpea genotypes. Three breeding populations developed separately through complex crosses, double crosses and simple crosses were advanced under rainfed environments in multiple sick-plot during 1994-01. Selection for various traits like number of branches, number of pods, seed yield, tolerance to drought and resistance against soil brome diseased was exercised in spaced planted population in each cross separately. The superior performing genotypes from complex crosses, double crosses and simple crosses were also evaluated under rainfed conditions during 2001-03. The relative performance was analyzed for various traits and results obtained showed that the general mean of different traits of new genotypes developed through complex and double crosses was significantly higher than those new genotypes developed from simple crosses and well adopted check varieties. It is interesting to mention that the yield superiority was ranging between 23 to 59 per cent, coupled with drought tolerance and resistance against Fusarium wilt. The performance in respect to number of branches, number of pods and biomass production was also observed more or less of the some patterns in these crosses. Considering these findings it was concluded that though drought stress tolerance is influenced and controlled by many environmental factors even than the effective genetic manipulations and breeding approaches can provide a very effective tool in producing drought tolerant chickpea genotypes. Based on these findings it is suggested that legumes breeder are required to develop segregating populations through complex crosses and generation advancement may be carried out under unfavorable environments or water limiting conditions.