Register      Login
Crop and Pasture Science Crop and Pasture Science Society
Plant sciences, sustainable farming systems and food quality
RESEARCH ARTICLE

Yield improvement and adaptation of wheat to water-limited environments in Australia—a case study

R. A. Richards A B , J. R. Hunt A , J. A. Kirkegaard A and J. B. Passioura A
+ Author Affiliations
- Author Affiliations

A CSIRO Agriculture Flagship, PO Box 1600, Canberra, ACT, 2601, Australia.

B Corresponding author. Email: Richard.Richards@csiro.au

Crop and Pasture Science 65(7) 676-689 https://doi.org/10.1071/CP13426
Submitted: 6 December 2013  Accepted: 2 June 2014   Published: 7 August 2014

Abstract

The improvement in grain yield of wheat throughout Australia through both breeding and management has been impressive. Averaged across all farms, there has been an approximate doubling of yield per unit area since ~1940. This has occurred across a broad range of environments with different rainfall patterns. Interestingly, the gain in the driest years (9 kg ha–1 year–1 or 0.81% year–1) has been proportionally greater than in the most favourable years (13.2 kg ha–1 year–1 or 0.61% per year) when expressed as yield relative to 2012. These data from all farms suggest that further yield progress is likely, and evidence is presented that improved management practices alone could double this rate of progress. The yield increases achieved have been without any known compromise in grain quality or disease resistance.

As expected, improvements have come from both changed management and from better genetics, as well as from the synergy between them. Yield improvements due to changed management have been dramatic and are easiest to quantify, whereas those from breeding have been important but more subtle. The management practices responsible have largely been driven by advances in mechanisation that enable direct seeding, more timely and flexible sowing and nutrient management, and improved weed and pest control, many of which have been facilitated by improved crop sequences with grain legumes and oilseeds that improve water- and nutrient-use efficiency. Most of the yield improvements from breeding in Australia have come from conventional breeding approaches where selection is almost solely for grain yield (together with grain quality and disease resistance). Improvements have primarily been through increased harvest index (HI), although aboveground biomass has also been important.

We discuss future opportunities to further increase Australian rainfed wheat yields. An important one is earlier planting, which increases resource capture. This will require knowledge of the genes regulating phenological development so that flowering still occurs at the optimum time; appropriate modifications to sowing arrangements and nutrient management will also be required. To improve yield potential, we propose a focus on physiological traits that increase biomass and HI and suggest that there may be more scope to improve biomass than HI. In addition, there are likely to be important opportunities to combine novel management practices with new breeding traits to capture the synergy possible from variety × management interactions. Finally, we comment on research aimed at adapting agriculture to climate change.

Additional keywords: biomass, breeding, harvest index, management, sowing date, water-use efficiency, climate change.


References

Acuña TB, Dean G, Riffkin P (2011) Constraints to achieving high potential yield of wheat in a temperate, high-rainfall environment in south-eastern Australia. Crop & Pasture Science 62, 125–136.
Constraints to achieving high potential yield of wheat in a temperate, high-rainfall environment in south-eastern Australia.Crossref | GoogleScholarGoogle Scholar |

Anderson WK (2010) Closing the gap between actual and potential yield of rainfed wheat. The impacts of environment, management and cultivar. Field Crops Research 116, 14–22.
Closing the gap between actual and potential yield of rainfed wheat. The impacts of environment, management and cultivar.Crossref | GoogleScholarGoogle Scholar |

Anderson WK, Smith WR (1990) Increasing wheat yields in a high rainfall area of Western Australia. Australian Journal of Experimental Agriculture 30, 607–614.
Increasing wheat yields in a high rainfall area of Western Australia.Crossref | GoogleScholarGoogle Scholar |

Anderson WK, Hamza MA, Sharma DL, D’Antuono MF, Hoyle FC, Hill N, Shackley BJ, Amjad M, Zaicou-Kunesch C (2005) The role of management in yield improvement of the wheat crop – a review with special emphasis on Western Australia. Australian Journal of Agricultural Research 56, 1137–1149.
The role of management in yield improvement of the wheat crop – a review with special emphasis on Western Australia.Crossref | GoogleScholarGoogle Scholar |

Angus JF (2001) Nitrogen supply and demand in Australian agriculture. Australian Journal of Experimental Agriculture 41, 277–288.
Nitrogen supply and demand in Australian agriculture.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXkt1CrsbY%3D&md5=cc9c8b48d30794bf44b4c93ea8249d4cCAS |

Angus JF, van Herwaarden AF (2001) Increasing water use and water use efficiency in dryland wheat. Agronomy Journal 93, 290–298.
Increasing water use and water use efficiency in dryland wheat.Crossref | GoogleScholarGoogle Scholar |

Angus J, Peoples M, Kirkegaard JA, Ryan MH, Ohlander L (2008) The value of break crops for wheat. In ‘Proceedings of 14th Australian Agronomy Conference’. Adelaide, S. Aust. (Ed. M. Unkovich) (Australian Society of Agronomy/The Regional Institute: Gosford, NSW) Available at: www.regional.org.au/au/asa/2008/concurrent/rotations/5786_angusjf.htm

Austin RB, Bingham J, Blackwell RD, Evans LT, Ford MA, Morgan CL, Taylor M (1980) Genetic improvements in winter-wheat yields since 1900 and associated physiological-changes. The Journal of Agricultural Science 94, 675–689.
Genetic improvements in winter-wheat yields since 1900 and associated physiological-changes.Crossref | GoogleScholarGoogle Scholar |

Batten GD, Fettell NA, Mead JA, Khan MA (1999) Effect of sowing date on the uptake and utilisation of phosphorus by wheat (cv. Osprey) grown in central New South Wales. Australian Journal of Experimental Agriculture 39, 161–170.
Effect of sowing date on the uptake and utilisation of phosphorus by wheat (cv. Osprey) grown in central New South Wales.Crossref | GoogleScholarGoogle Scholar |

Bell LW, Moore AD, Kirkegaard JA (2014) Evolution in crop–livestock integration systems that improve farm productivity and environmental performance in Australia. European Journal of Agronomy 57, 10–20.
Evolution in crop–livestock integration systems that improve farm productivity and environmental performance in Australia.Crossref | GoogleScholarGoogle Scholar |

Black I, Dyson C, Hayman P, Alexander B (2008) The determinants of South Australian wheat yield increases. In ‘Proceedings 14th Australian Agronomy Conference’. Adelaide, S. Aust. (Ed. M. Unkovich) (Australian Society of Agronomy/The Regional Institute: Gosford, NSW) Available at: www.regional.org.au/au/asa/2008/concurrent/evaluating-systems/5837_blackid.htm

Brennan JP (1984) Measuring the contribution of new varieties to increasing wheat yields. Review of Marketing and Agricultural Economics 52, 175–195.

Bustos DV, Hasan AK, Reynolds MP, Calderini DF (2013) Combining high grain number and weight through a DH-population to improve grain yield potential of wheat in high-yielding environments. Field Crops Research 145, 106–115.
Combining high grain number and weight through a DH-population to improve grain yield potential of wheat in high-yielding environments.Crossref | GoogleScholarGoogle Scholar |

Cane K, Eagles HA, Laurie DA, Trevaskis B, Vallance N, Eastwood RF, Gororo NN, Kuchel H, Martin PJ (2013) Ppd-B1 and Ppd-D1 and their effects in southern Australian wheat. Crop & Pasture Science 64, 100–114.
Ppd-B1 and Ppd-D1 and their effects in southern Australian wheat.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhtVWhtr3E&md5=5a7ab06bccefff8fa9c46eff919c219fCAS |

Carberry PS, Hochman Z, Hunt JR, Dalgliesh NP, McCown RL, Whish JPM, Robertson MJ, Foale MA, Poulton PL, van Rees H (2009) Re-inventing model-based decision support with Australian dryland farmers. 3. Relevance of APSIM to commercial crops. Crop & Pasture Science 60, 1044–1056.
Re-inventing model-based decision support with Australian dryland farmers. 3. Relevance of APSIM to commercial crops.Crossref | GoogleScholarGoogle Scholar |

Condon AG, Richards RA, Farquhar GD (1987) Carbon isotope discrimination is positively correlated with grain-yield and dry-matter production in field-grown wheat. Crop Science 27, 996–1001.
Carbon isotope discrimination is positively correlated with grain-yield and dry-matter production in field-grown wheat.Crossref | GoogleScholarGoogle Scholar |

Cooper M, Stucker RE, DeLacy IH, Harch BD (1997) Wheat breeding nurseries, target environments, and indirect selection for grain yield. Crop Science 37, 1168–1176.
Wheat breeding nurseries, target environments, and indirect selection for grain yield.Crossref | GoogleScholarGoogle Scholar |

Davidson JL, Birch JW (1980) Yield trends from Australian wheats. In ‘Pathways to productivity. Proceedings of the Australian Agronomy Conference’. (Ed. IM Wood) pp. 231–231. (Australian Society of Agronomy)

Davidson J, Christian K, Jones D, Bremner P (1985) Responses of wheat to vernalization and photoperiod. Australian Journal of Agricultural Research 36, 347–359.
Responses of wheat to vernalization and photoperiod.Crossref | GoogleScholarGoogle Scholar |

Donald CM (1965) The progress of Australian agriculture and the role of pastures in environmental change. Australian Journal of Agricultural Science 27, 187–198.

Eagles HA, Cane K, Vallance N (2009) The flow of alleles of important photoperiod and vernalisation genes through Australian wheat. Crop & Pasture Science 60, 646–657.
The flow of alleles of important photoperiod and vernalisation genes through Australian wheat.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXosVymtbo%3D&md5=0b0a2ed25ffdab483c69efe562a2ddfdCAS |

Eagles HA, Cane K, Kuchel H, Hollamby GJ, Vallance N, Eastwood RF, Gororo NN, Martin PJ (2010) Photoperiod and vernalization gene effects in southern Australian wheat. Crop & Pasture Science 61, 721–730.
Photoperiod and vernalization gene effects in southern Australian wheat.Crossref | GoogleScholarGoogle Scholar |

Ellis MH, Rebetzke GJ, Azanza F, Richards RA, Spielmeyer W (2005) Molecular mapping of gibberellin-responsive dwarfing genes in bread wheat. Theoretical and Applied Genetics 111, 423–430.
Molecular mapping of gibberellin-responsive dwarfing genes in bread wheat.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXovVKktLc%3D&md5=0616a6e9e272e2d8203abc506bc1aa29CAS | 15968526PubMed |

Fischer RA (1979) Growth and water limitation to dryland wheat yield: A physiological framework. Journal Australian Institute Agricultural Science 45, 83–94.

Fischer RA (1985) Number of kernels in wheat crops and the influence of solar-radiation and temperature. Journal of Agricultural Science 105, 447–461.

Fischer RA (2007) Understanding the physiological basis of yield potential in wheat. The Journal of Agricultural Science 145, 99–113.
Understanding the physiological basis of yield potential in wheat.Crossref | GoogleScholarGoogle Scholar |

Fischer R (2009) Farming systems of Australia: Exploiting the synergy between genetic improvement and agronomy. In ‘Crop physiology: applications for genetic improvement and agronomy’. (Eds VO Sadras, D Calderini) pp. 23–54. (Elsevier: Amsterdam)

Fischer RA, Stockman YM (1986) Increased kernel number in Norin 10-derived dwarf wheat – evaluation of the cause. Australian Journal of Plant Physiology 13, 767–784.
Increased kernel number in Norin 10-derived dwarf wheat – evaluation of the cause.Crossref | GoogleScholarGoogle Scholar |

Fischer RA, Byerlee D, Edmeades GO (2014) ‘Crop yields and global food security: will yield increase continue to feed the world?’ ACIAR Monograph No. 158. (Australian Centre for International Agricultural Research: Canberra, ACT)

French RJ, Schultz JE (1984) Water-use efficiency of wheat in a Mediterranean-type environment. 1. The relation between yield, water-use and climate. Australian Journal of Agricultural Research 35, 743–764.
Water-use efficiency of wheat in a Mediterranean-type environment. 1. The relation between yield, water-use and climate.Crossref | GoogleScholarGoogle Scholar |

Gifford RM (1979) Growth and yield of CO2-enriched wheat under water-limited conditions. Australian Journal of Plant Physiology 6, 367–378.
Growth and yield of CO2-enriched wheat under water-limited conditions.Crossref | GoogleScholarGoogle Scholar |

Gomez-Macpherson H, Richards RA (1995) Effect of sowing time on yield and agronomic characteristics of wheat in south-eastern Australia. Australian Journal of Agricultural Research 46, 1381–1399.
Effect of sowing time on yield and agronomic characteristics of wheat in south-eastern Australia.Crossref | GoogleScholarGoogle Scholar |

González FG, Slafer GA, Miralles DJ (2005) Pre-anthesis development and number of fertile florets in wheat as affected by photoperiod sensitivity genes Ppd-D1 and Ppd-B1. Euphytica 146, 253–269.
Pre-anthesis development and number of fertile florets in wheat as affected by photoperiod sensitivity genes Ppd-D1 and Ppd-B1.Crossref | GoogleScholarGoogle Scholar |

GRDC (2011) Impact on yield and quality of wheat. Southern region. GRDC Time of Sowing Fact Sheet. Grains Research and Development Corporation, Barton, ACT. Available at: www.grdc.com.au/~/media/215DF373683A4ABD999F94B3BDD3B5B0.pdf

Harrison MT, Evans JR, Dove H, Moore AD (2011) Recovery dynamics of rainfed winter wheat after livestock grazing 1. Growth rates, grain yields, soil water use and water-use efficiency. Crop & Pasture Science 62, 947–959.
Recovery dynamics of rainfed winter wheat after livestock grazing 1. Growth rates, grain yields, soil water use and water-use efficiency.Crossref | GoogleScholarGoogle Scholar |

Hochman Z, Holzworth D, Hunt JR (2009) Potential to improve on-farm wheat yield and WUE in Australia. Crop & Pasture Science 60, 708–716.
Potential to improve on-farm wheat yield and WUE in Australia.Crossref | GoogleScholarGoogle Scholar |

Hochman Z, Gobbett D, Holzworth D, McClelland T, van Rees H, Marinoni O, Garcia JN, Horan H (2012) Quantifying yield gaps in rainfed cropping systems: A case study of wheat in Australia. Field Crops Research 136, 85–96.
Quantifying yield gaps in rainfed cropping systems: A case study of wheat in Australia.Crossref | GoogleScholarGoogle Scholar |

Hunt JR, Kirkegaard JA (2011) Re-evaluating the contribution of summer fallow rain to wheat yield in southern Australia. Crop & Pasture Science 62, 915–929.
Re-evaluating the contribution of summer fallow rain to wheat yield in southern Australia.Crossref | GoogleScholarGoogle Scholar |

Jefferies SP, Pallotta MA, Paull JG, Karakousis A, Kretschmer JM, Manning S, Islam A, Langridge P, Chalmers KJ (2000) Mapping and validation of chromosome regions conferring boron toxicity tolerance in wheat (Triticum aestivum). Theoretical and Applied Genetics 101, 767–777.
Mapping and validation of chromosome regions conferring boron toxicity tolerance in wheat (Triticum aestivum).Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXosFyhurg%3D&md5=b30ba9f93aff02c20550a7a4c45ac396CAS |

Kirby EJM, Siddique KHM, Perry MW, Kaesehagen D, Stern WR (1989) Variation in spikelet initiation and ear development of old and modern Australian wheat varieties. Field Crops Research 20, 113–128.
Variation in spikelet initiation and ear development of old and modern Australian wheat varieties.Crossref | GoogleScholarGoogle Scholar |

Kirkegaard JA, Hunt JR (2010) Increasing productivity by matching farming system management and genotype in water-limited environments. Journal of Experimental Botany 61, 4129–4143.
Increasing productivity by matching farming system management and genotype in water-limited environments.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXhtlShtLnL&md5=c496fc7a1fb68f86892bab8d39910ce2CAS | 20709725PubMed |

Kirkegaard JA, Peoples MB, Angus JF, Unkovich MJ (2011) Diversity and evolution of rainfed farming systems in southern Australia. In ‘Rainfed farming systems’. (Eds P Tow, I Cooper, I Partridge, C Birch) pp. 715–754. (Springer: Dordrecht, The Netherlands)

Leakey ADB, Ainsworth EA, Bernacchi CJ, Rogers A, Long SP, Ort DR (2009) Elevated CO2 effects on plant carbon, nitrogen, and water relations: six important lessons from FACE. Journal of Experimental Botany 60, 2859–2876.
Elevated CO2 effects on plant carbon, nitrogen, and water relations: six important lessons from FACE.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXosFWjtLc%3D&md5=cdd2c403bd090fbe5bb9592d9a707cc7CAS |

Lilley JM, Kirkegaard JA (2011) Benefits of increased soil exploration by wheat roots. Field Crops Research 122, 118–130.
Benefits of increased soil exploration by wheat roots.Crossref | GoogleScholarGoogle Scholar |

MacIndoe SL (1937) An Australian ‘winter’ wheat. Journal of the Australian Institute of Agricultural Science 3, 219–224.

McDonald GK, Taylor JD, Verbyla A, Kuchel H (2012) Assessing the importance of subsoil constraints to yield of wheat and its implications for yield improvement. Crop & Pasture Science 63, 1043–1065.
Assessing the importance of subsoil constraints to yield of wheat and its implications for yield improvement.Crossref | GoogleScholarGoogle Scholar |

Miralles DJ, Richards RA, Slafer GA (2000) Duration of the stem elongation period influences the number of fertile florets in wheat and barley. Australian Journal of Plant Physiology 27, 931–940.

Nix HA (1975) The Australian climate and its effects on grain yield and quality. In ‘Australian field crops, wheat and other temperate cereals’. (Eds A Lazenby, EM Matheson) pp. 83–226. (Angus and Robertson: Sydney)

O’Brien L (1982) Victorian wheat yield trends, 1898–1977. Journal of the Australian Institute of Agricultural Science 48, 163–168.

Ogbonnaya FC, Subrahmanyam NC, Moullet O, de Majnik J, Eagles HA, Brown JS, Eastwood RF, Kollmorgen J, Appels R, Lagudah ES (2001) Diagnostic DNA markers for cereal cyst nematode resistance in bread wheat. Australian Journal of Agricultural Research 52, 1367–1374.
Diagnostic DNA markers for cereal cyst nematode resistance in bread wheat.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XltlOlsw%3D%3D&md5=9809f768e352fe84362ed7c767079a16CAS |

Ortiz-Monasterio JI, Sayre KD, Rajaram S, McMahon M (1997) Genetic progress in wheat yield and nitrogen use efficiency under four nitrogen rates. Crop Science 37, 898–904.
Genetic progress in wheat yield and nitrogen use efficiency under four nitrogen rates.Crossref | GoogleScholarGoogle Scholar |

Passioura JB (1977) Grain-yield, harvest index, and water-use of wheat. Journal of the Australian Institute of Agricultural Science 43, 117–120.

Passioura JB, Angus JF (2010) Improving productivity of crops in water-limited environments. In ‘Advances in agronomy, Vol. 106’. (Ed. DL Sparks) pp. 37–75. (Elsevier: Amsterdam)

Perry MW, D’Antuono MF (1989) Yield improvement and associated characteristics of some Australian spring wheat cultivars introduced between 1860 and 1982. Australian Journal of Agricultural Research 40, 457–472.

Powell N, Ji X, Ravash R, Edlington J, Dolferus R (2012) Yield stability for cereals in a changing climate. Functional Plant Biology 39, 539–552.
Yield stability for cereals in a changing climate.Crossref | GoogleScholarGoogle Scholar |

Puckridge DW, French RJ (1983) The annual legume pasture in cereal ley farming systems of southern Australia—a review. Agriculture, Ecosystems & Environment 9, 229–267.
The annual legume pasture in cereal ley farming systems of southern Australia—a review.Crossref | GoogleScholarGoogle Scholar |

Raman H, Zhang KR, Cakir M, Appels R, Garvin DF, Maron LG, Kochian LV, Moroni JS, Raman R, Imtiaz M, Drake-Brockman F, Waters I, Martin P, Sasaki T, Yamamoto Y, Matsumoto H, Hebb DM, Delhaize E, Ryan PR (2005) Molecular characterization and mapping of ALMT1, the aluminium-tolerance gene of bread wheat (Triticum aestivum L.). Genome 48, 781–791.
Molecular characterization and mapping of ALMT1, the aluminium-tolerance gene of bread wheat (Triticum aestivum L.).Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XkslSnug%3D%3D&md5=489230ee513bae7c805aaf82b5ced355CAS | 16391684PubMed |

Rawson HM (1988) Effects of high temperatures on the development and yield of wheat and practices to reduce deleterious effects. In ‘Wheat production constraints in tropical environments. Proceedings of the International Conference’. January 1987, Chiang Mai, Thailand. (Ed. AR Klatt) pp. 44–62. (UNDP, CIMMYT)

Rebetzke GJ, Richards RA, Fettell NA, Long M, Condon AG, Forrester RI, Botwright TL (2007) Genotypic increases in coleoptile length improves stand establishment, vigour and grain yield of deep-sown wheat. Field Crops Research 100, 10–23.
Genotypic increases in coleoptile length improves stand establishment, vigour and grain yield of deep-sown wheat.Crossref | GoogleScholarGoogle Scholar |

Rebetzke GJ, van Herwaarden AF, Jenkins C, Weiss M, Lewis D, Ruuska S, Tabe L, Fettell NA, Richards RA (2008) Quantitative trait loci for water-soluble carbohydrates and associations with agronomic traits in wheat. Australian Journal of Agricultural Research 59, 891–905.
Quantitative trait loci for water-soluble carbohydrates and associations with agronomic traits in wheat.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXhtFaisrfE&md5=aea35f455c8423e3c40290c2ce77abc5CAS |

Rebetzke GJ, Rattey AR, Farquhar GD, Richards RA, Condon AG (2013) Genomic regions for canopy temperature and their genetic association with stomatal conductance and grain yield in wheat. Functional Plant Biology 40, 14–33.
Genomic regions for canopy temperature and their genetic association with stomatal conductance and grain yield in wheat.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XhvVertLnI&md5=3cf9fe8151ea89fbac6dfcd8f14347e4CAS |

Richards RA (1991) Crop improvement for temperate Australia—future opportunities. Field Crops Research 26, 141–169.
Crop improvement for temperate Australia—future opportunities.Crossref | GoogleScholarGoogle Scholar |

Richards RA (1992) The effect of dwarfing genes in spring wheat in dry environments. 1. Agronomic characteristics. Australian Journal of Agricultural Research 43, 517–527.
The effect of dwarfing genes in spring wheat in dry environments. 1. Agronomic characteristics.Crossref | GoogleScholarGoogle Scholar |

Richards RA, Rebetzke GJ, Condon AG, van Herwaarden AF (2002) Breeding opportunities for increasing the efficiency of water use and crop yield in temperate cereals. Crop Science 42, 111–121.
Breeding opportunities for increasing the efficiency of water use and crop yield in temperate cereals.Crossref | GoogleScholarGoogle Scholar | 11756261PubMed |

Richards RA, Rebetzke GJ, Watt M, Condon AG, Spielmeyer W, Dolferus R (2010) Breeding for improved water productivity in temperate cereals: phenotyping, quantitative trait loci, markers and the selection environment. Functional Plant Biology 37, 85–97.
Breeding for improved water productivity in temperate cereals: phenotyping, quantitative trait loci, markers and the selection environment.Crossref | GoogleScholarGoogle Scholar |

Richardson AEV (1923) The water requirements of farm crops. Influence of environment on transpiration ratio. The Journal of the Department of Agriculture, Victoria 21, 193–284.

Richardson AEV, Trumble HC (1928) The transpiration ratio of farm crops and pasture plants in the Adelaide district. Journal Department of Agriculture South Australia 32, 224–244.

Rodriguez D, Sadras VO (2007) The limit to wheat water-use efficiency in eastern Australia. I. Gradients in the radiation environment and atmospheric demand. Australian Journal of Agricultural Research 58, 287–302.
The limit to wheat water-use efficiency in eastern Australia. I. Gradients in the radiation environment and atmospheric demand.Crossref | GoogleScholarGoogle Scholar |

Sadras VO (2005) A quantitative top-down view of interactions between stresses: theory and analysis of nitrogen–water co-limitation in Mediterranean agro-ecosystems. Australian Journal of Agricultural Research 56, 1151–1157.
A quantitative top-down view of interactions between stresses: theory and analysis of nitrogen–water co-limitation in Mediterranean agro-ecosystems.Crossref | GoogleScholarGoogle Scholar |

Sadras VO, Lawson C (2011) Genetic gain in yield and associated changes in phenotype, trait plasticity and competitive ability of South Australian wheat varieties released between 1958 and 2007. Crop & Pasture Science 62, 533–549.
Genetic gain in yield and associated changes in phenotype, trait plasticity and competitive ability of South Australian wheat varieties released between 1958 and 2007.Crossref | GoogleScholarGoogle Scholar |

Sadras VO, Lawson C (2013) Nitrogen and water-use efficiency of Australian wheat varieties released between 1958 and 2007. European Journal of Agronomy 46, 34–41.
Nitrogen and water-use efficiency of Australian wheat varieties released between 1958 and 2007.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXisVaktLs%3D&md5=3da897d9b03628f16c250fa6fc63dd6cCAS |

Sadras VO, Richards RA (2014) Improvement of crop yield in dry environments: benchmarks, levels of organisation and the role of nitrogen. Journal of Experimental Botany 65, 1981–1995.
Improvement of crop yield in dry environments: benchmarks, levels of organisation and the role of nitrogen.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2cXmsVGkurk%3D&md5=17d7dca76a108e03ff7ece6dbc5266f2CAS | 24638898PubMed |

Sadras VO, Rodriguez D (2007) The limit to wheat water-use efficiency in eastern Australia. II. Influence of rainfall patterns. Australian Journal of Agricultural Research 58, 657–669.
The limit to wheat water-use efficiency in eastern Australia. II. Influence of rainfall patterns.Crossref | GoogleScholarGoogle Scholar |

Sadras VO, Lawson C, Montoro A (2012) Photosynthetic traits in Australian wheat varieties released between 1958 and 2007. Field Crops Research 134, 19–29.
Photosynthetic traits in Australian wheat varieties released between 1958 and 2007.Crossref | GoogleScholarGoogle Scholar |

Saunders R (2008) Grain yield of heritage wheat varieties in South Australian Mallee. In ‘Proceedings of 14th Australian Agronomy Conference’. Adelaide, S. Aust. (Ed. M Unkovich) (Australian Society of Agronomy/The Regional Institute: Gosford, NSW) Available at: www.regional.org.au/au/asa/2008/poster/farmer-focussed-research/5797_saundersr.htm

Sayre KD, Rajaram S, Fischer RA (1997) Yield potential progress in short bread wheats in northwest Mexico. Crop Science 37, 36–42.
Yield potential progress in short bread wheats in northwest Mexico.Crossref | GoogleScholarGoogle Scholar |

Seymour M, Kirkegaard JA, Peoples MB, White PF, French RJ (2012) Break-crop benefits to wheat in Western Australia—insights from over three decades of research. Crop & Pasture Science 63, 1–16.
Break-crop benefits to wheat in Western Australia—insights from over three decades of research.Crossref | GoogleScholarGoogle Scholar |

Sharma DL, D’Antuono MF, Anderson WK, Shackley BJ, Zaicou-Kunesch CM, Amjad M (2008) Variability of optimum sowing time for wheat yield in Western Australia. Australian Journal of Agricultural Research 59, 958–970.
Variability of optimum sowing time for wheat yield in Western Australia.Crossref | GoogleScholarGoogle Scholar |

Shearman VJ, Sylvester-Bradley R, Scott RK, Foulkes MJ (2005) Physiological processes associated with wheat yield progress in the UK. Crop Science 45, 175–185.

Shi G, Ribbe J, Cai W, Cowan T (2008) An interpretation of Australian rainfall projections. Geophysical Research Letters 35, L02702
An interpretation of Australian rainfall projections.Crossref | GoogleScholarGoogle Scholar |

Siddique KHM, Belford RK, Perry MW, Tennant D (1989a) Growth, development and light interception of old and modern wheat cultivars in a Mediterranean-type environment. Australian Journal of Agricultural Research 40, 473–487.

Siddique KHM, Kirby EJM, Perry MW (1989b) Ear stem ratio in old and modern wheat-varieties—relationship with improvement in number of grains per ear and yield. Field Crops Research 21, 59–78.
Ear stem ratio in old and modern wheat-varieties—relationship with improvement in number of grains per ear and yield.Crossref | GoogleScholarGoogle Scholar |

Siddique KHM, Tennant D, Perry MW, Belford RK (1990) Water-use and water-use efficiency of old and modern wheat cultivars in a mediterranean-type environment. Australian Journal of Agricultural Research 41, 431–447.
Water-use and water-use efficiency of old and modern wheat cultivars in a mediterranean-type environment.Crossref | GoogleScholarGoogle Scholar |

Sinclair TR, Rufty TW (2012) Nitrogen and water resources commonly limit crop yield increases, not necessarily plant genetics. Global Food Security 1, 94–98.
Nitrogen and water resources commonly limit crop yield increases, not necessarily plant genetics.Crossref | GoogleScholarGoogle Scholar |

Stephens DJ, Lyons TJ (1998) Variability and trends in sowing dates across the Australian wheatbelt. Australian Journal of Agricultural Research 49, 1111–1118.
Variability and trends in sowing dates across the Australian wheatbelt.Crossref | GoogleScholarGoogle Scholar |

Sun F, Roderick ML, Lim WH, Farquhar GD (2011) Hydroclimatic projections for the Murray–Darling Basin based on an ensemble derived from Intergovernmental Panel on Climate Change AR4 climate models. Water Resources Research 47, W00G02
Hydroclimatic projections for the Murray–Darling Basin based on an ensemble derived from Intergovernmental Panel on Climate Change AR4 climate models.Crossref | GoogleScholarGoogle Scholar |

Tausz-Posch S, Norton RM, Seneweera S, Fitzgerald GJ, Tausz M (2013) Will intra-specific differences in transpiration efficiency in wheat be maintained in a high CO2 world? A FACE study. Physiologia Plantarum 148, 232–245.
Will intra-specific differences in transpiration efficiency in wheat be maintained in a high CO2 world? A FACE study.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXptlOgu7Y%3D&md5=164eaf7c53b346c52332305d932a9392CAS | 23035842PubMed |

Vandeleur RK, Gill GS (2004) The impact of plant breeding on the grain yield and competitive ability of wheat in Australia. Australian Journal of Agricultural Research 55, 855–861.
The impact of plant breeding on the grain yield and competitive ability of wheat in Australia.Crossref | GoogleScholarGoogle Scholar |

Wall GW, Garcia RL, Kimball BA, Hunsaker DJ, Pinter PJ, Long SP, Osborne CP, Hendrix DL, Wechsung F, Wechsung G, Leavitt SW, LaMorte RL, Idso SB (2006) Interactive effects of elevated carbon dioxide and drought on wheat. Agronomy Journal 98, 354–381.
Interactive effects of elevated carbon dioxide and drought on wheat.Crossref | GoogleScholarGoogle Scholar |

Williams KJ, Taylor SP, Bogacki P, Pallotta M, Bariana HS, Wallwork H (2002) Mapping of the root lesion nematode (Pratylenchus neglectus) resistance gene Rlnn1 in wheat. Theoretical and Applied Genetics 104, 874–879.
Mapping of the root lesion nematode (Pratylenchus neglectus) resistance gene Rlnn1 in wheat.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XktlWnt7Y%3D&md5=0a2abc2b90d19cb669691b615b5b7fa1CAS |

Zhang H, Turner NC, Poole ML, Simpson N (2006) Crop production in the high rainfall zones of southern Australia—potential, constraints and opportunities. Australian Journal of Experimental Agriculture 46, 1035–1049.
Crop production in the high rainfall zones of southern Australia—potential, constraints and opportunities.Crossref | GoogleScholarGoogle Scholar |