The objective of this  project was to assess the yield potential of novel bread wheat germplasms developed by SARDI (Mace/MW#293 genetic population) and University of Adelaide (Mocho de Espiga Branca genetic population) for improved yield potential in a water limited environment. For comparison,  twenty bread wheat cultivars released between 1958 and 2022 were also included in the trial. Parental lines of these two genetic populations, MW#293 and Mocho de Espiga Branca, accumulate unusually high levels of sodium in their leaves. This high sodium accumulation presumably provides a better osmotic adjustment which in turn enables the plant to draw more water which is otherwise unavailable due to high salt in soil solution. The hypothesis here is that higher water uptake would lead to higher yields. This may also be true for drought as drought and salinity have similar effects on plant water uptake. A trial was established at Roseworthy Campus to test this hypothesis and determine yield potential of novel germplasms. Unfortunately, there was less than ideal crop establishment with 50% of the plots having less than 80% establishment. This was further complicated by the unexpected late heavy rains which caused by up to 90% pre-harvest sprouting. This resulted in reduced grain weight and quality. For these reasons, grain yield analysis could not be performed, and yield potential of novel wheat germplasms could not be determined. However, we observed germplasm lines with longer and wider spikes than commercial wheats, which is exciting as this indicates higher grain numbers.  This higher grain number per spike trait was expressed despite a very dry year indicating this trait’s yield potential across different environments. The spike samples are currently being scanned by X-ray CT (The plant Accelerator, University of Adelaide) to validate visual observations and identify germplasm lines with increased grain number for breeding and further evaluation in multiple environments. However, how the increased grain number relates to yield could not be assessed. For this, this work needs to be repeated if/when further  funding is secured.

Project description: 

The proposed project addresses the SA Drought Hub objective of ‘enhancing drought resilience and recovery across all farming sectors’ and National Agricultural Innovation Priority 2. ‘Australia will champion climate resilience to increase the productivity, profitability and sustainability of the agricultural sector by 2030’. It fits within Activity 2 ‘deliver demonstration sties to increase adoption of existing research’.   

Drought is the most prevalent abiotic stress affecting production of wheat in Australia. Over the last three decades, there has been a significant GRDC and state investment into understanding drought tolerance (ability to maintain biomass and yield under drought conditions) and its mechanisms. As a result, researchers have identified mechanisms related to the capacity of plants to tolerate drought, the genetic variation available within breeding germplasm and diagnostic markers for genes of interest. Despite these advances, there remains strong grower interest in the development of varieties that incorporate further drought tolerance.  

Objectives  

To demonstrate, and field-assess wheat lines designed to accumulate salt (at 100x wheat cultivar Mace) in their leaves rather than exclude salt at root level. This accumulation mechanism opens the possibility of improved water use efficiency through osmotic adjustment. This novel germplasm is the result of ten years of sustained effort by The University of Adelaide (UoA) and SARDI researchers and represents an exciting opportunity to stabilise yield under rainfed conditions. 

The project lead, Dr Yusuf Genc, worked with colleagues at UoA, SARDI and CSSSA to develop a field demonstration site to assess the germplasm for traits that contribute to stable yield, and to extend these findings to growers, consultants and breeders. We expect germplasm with advantageous traits will be taken up by plant breeding companies for further development, providing growers with expanded variety options for dry years and assisting them to reduce risk and improve mixed farming resilience.  

Aims: 

1. To assess the potential of 460 novel fixed bread wheat lines for improved water use efficiency on constrained soil types and compare growth and yield against 24 historical and current bread wheat varieties.  

1. Coordinated by The Crop Science Society of South Australia (CSSSA), a society of c. 450 members, showcase the germplasm in the field to growers, consultants, and breeding companies. 

Key achievements and results: 

The proposed project addresses the SA Drought Hub objective of ‘enhancing drought resilience and recovery across all farming sectors’ and National Agricultural Innovation Priority 2. ‘Australia will champion climate resilience to increase the productivity, profitability and sustainability of the agricultural sector by 2030’. It fits within Activity 2 ‘deliver demonstration sties to increase adoption of existing research’.

SA Drought Hub funding was obtained to field assess yield potential of two novel bread wheat genetic populations with varying levels of sodium (Na⁺) uptake (Mace/MW#293 and Mocho de Espiga Branco /Gladius), and bench mark them against a historical set of 24 wheat varieties (released between 1958 and 2022). The expectation was to identify lines with superior performance to currently available germplasm under water limited or soil constrained environments due to a capacity to utilise accumulated Na+ as an osmotic adjustment mechanism leading to improved water use efficiency.

The trial was conducted at Roseworthy campus of University of Adelaide. A number of grower groups, breeders and researchers visited the field site and expressed that they felt the work conducted was important.  Unfortunately, we encountered crop establishment issues and unseasonal late rains causing significant damage to grains, hence, we could not perform yield analysis to determine yield potential of novel wheat germplasm against historical wheats. However, we observed germplasm lines with longer and wider spikes than commercial wheats, which is exciting as this indicates higher grain numbers.  This higher grain number per spike trait was expressed despite a very dry year indicating this trait’s yield potential across different environments. The spike samples are currently being scanned by X-ray CT (The plant Accelerator, University of Adelaide) to validate visual observations and identify germplasm lines with increased grain number for breeding and further evaluation in multiple environments. However, how the increased grain number relates to yield could not be assessed. For this, this work needs to be repeated if/when further funding is secured.