Ground Cover Supplement : GC Supplement - Wheat pre-breeding
GROUNDCOVER 11 Issue 127 | March – April 2017 | GRDC GROUNDCOVERTM SUPPLEMENT: WHEAT PRE-BREEDING CONTEN????ITORIAL Dr Stuart Roy SOIL SALINITY to improve salinity tolerance, usually assessing the ability of plants to tolerate stress under controlled environmental conditions, in either pots of soil or hydroponics. These studies have focused on identifying and characterising salinity- tolerance mechanisms that can improve plant growth, such as the ability of plants to maintain shoot growth, exclude toxic concentrations of Na+ and/or Cl- from the roots or compartmentalise these ions in specialised organelles in the cells to better tolerate their toxic effects. Through these studies several different salt-tolerance mechanisms have been discovered, along with the alleles (regions of DNA) controlling them. However, crucial for the translation of this research into products for growers is the field validation of these traits and alleles. There are examples in drought research where alleles are beneficial in one environment and have a negative impact in another. It is important to find the right allele for the right environment. NATIONAL SALINITY EFFORT We have been working on a national GRDC-funded project to develop salinity- tolerant wheat and barley in collaborations between researchers at the Australian Centre for Plant Functional Genomics, the Australian Plant Phenomics Facility, the University of Adelaide, the University of Western Australia and CSIRO. The project aims have been to identify alleles for salinity-tolerance traits in the greenhouse, assess the impact of these potentially beneficial alleles on grain yield in saline and non-saline paddocks, develop molecular markers for salinity- tolerance traits for use in plant breeding programs, and start introducing the best salinity tolerance alleles into elite bread wheat and barley varieties. Populations of bread wheat and barley that allow genetic mapping of salt-tolerance traits were assessed for their ability to maintain shoot growth and produce a large biomass under salinity stress. They were also tested for their ability to either exclude or tolerate high concentrations of Na+ and Cl- in their leaves. We made substantial use of the Plant Accelerator (Australian Plant Phenomics Facility) for non-destructive plant growth measurements of salt-stressed plants and identified up to 50 potentially useful alleles for salinity-tolerance traits. To assess the effects of these new salt-tolerant alleles in the field, we tested the same wheat and barley populations over two years in both low and moderate saline field trial sites in South Australia (Whitwarta and Coomandook) and WA (Cunderdin). Several alleles for salinity tolerance that we identified in the greenhouse were validated and shown to correlate with significant improvements of grain yield (10 to 15 per cent) in the field. These alleles are now being introduced into elite lines of bread wheat and barley using marker-assisted selection. The ultimate goal is to progress this elite wheat and barley material containing salinity- tolerance alleles for future field assessment. While beneficial salinity-tolerance traits are now being introduced into elite cultivars, future work needs to focus on assessing the extent and impact of salinity in plant breeding trials and within growers’ paddocks. In the era of precision agriculture – where the use of unmanned aerial vehicles and large-scale, non- destructive field phenotyping is possible – one area still lags behind: precision mapping of soil constraints. The location of soil constraints varies across a field and often between growing seasons, even in paddocks deemed to have high productivity. As noted before, the yield of crops can be significantly affected by soil constraints without any visible plant symptoms. Mapping the heterogeneity of soil constraints, such as soil texture, salinity, pH and nutrient availability, through the use of technologies such as calibrated EM38 mapping, radiometry and pH probes, will be crucial to interpreting data received from UAVs, tractor-mounted sensors and non-destructive field-trial phenotyping. By combining infor mation on below- ground traits (including the heterogeneity of soil constraints) with that of above- ground traits (plant phenotypes and genetic infor mation), a more detailed understanding of how crops respond to environmental constraints has the potential to greatly assist growers, breeders and researchers in the future. o GRDC Research Code UA00145 More information: Dr Stuart Roy, firstname.lastname@example.org ACKNOWLEDGEMENTS Given the diversity of skills and environments that are needed to develop viable salt-tolerance traits, this project has only been possible as a collaborative endeavour that has included Professor Matthew Gilliham, Dr Bettina Berger, Dr Richard James, Professor Timothy Colmer, Professor Ed Barrett-Lennard, Dr Rhiannon Schilling, Dr Allison Pearson, Dr Caitlin Byrt, Dr Jiaen Qiu, Dr Alex Garcia, Kate Dowling and Dr Chris Brien, as well as growers who provided access to their fields in SA and WA, and South Australian Research and Development Institute and Kalyx Australia field teams. PHOTO:UNIVERSITYOFADELAIDEPHOTO:STUARTROY Salt-tolerance studies at the Plant Accelerator, South Australia.
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