For cereals, the floral developmental stage is very sensitive to high temperatures, which can cause structural and functional abnormalities to reproductive organs resulting in decreased fertility, seed-set and significant yield losses.
Management strategies include changing sowing date or crop type, but a genetic solution may also be achievable.
Dr Camilla Hill brings a breadth of experience to this task via a GRDC-invested capacity-building project. Originally from Germany, where she had close connections with her grandparents’ farm in Poland, her introduction to life in Australia was working as a backpacker on farms in South Australia and Queensland before undertaking a PhD at the University of Melbourne in wheat genetics in 2010. Her doctorate was supervised by Professors Antony Bacic and Ute Roessner within the Australian Centre for Plant Functional Genomics and supported by three University of Melbourne scholarships.
“My childhood interest inspired me to study biology at the Free University of Berlin, where I took a major in plant genetics and minors in plant physiology, molecular biology and biochemistry. As part of this study, I spent nine months conducting laboratory work for my master’s degree at Washington State University, funded by a German Academic Exchange Service Fellowship,” Dr Hill says.
Focus on environmental stresses
During her Phd she investigated physiological and biochemical traits as indicators of drought tolerance in a wheat mapping population grown under drought stress. She was keen to shift the focus of her research to the practical application of genetics to plant breeding.
Dr Hill joined Professor Chengdao Li’s team at Murdoch University’s Western Crop Genetics Alliance in 2015 on two consecutive GRDC-supported projects. Her current project aims to provide valuable information on heat-tolerant phenotypes and genotypes for spikelet fertility in response to heat stress, and to deliver new genetic resources to Australian barley breeders.
Genetic variability in spikelet fertility can be used by breeding programs to develop heat-tolerant genotypes. However, although considerable genetic variation for spikelet fertility has been reported in rice and wheat, comparatively little is known in barley and no candidate genes or molecular markers have been identified. This is the focus of my work.
Key research findings
More than 7000 genetic variants across 132 spikelet fertility and heat-tolerance-related genes have been identified. This information will allow the identification of new markers to breed barley varieties with enhanced spikelet fertility under heat stress.
Glasshouse trials, combined with heat chambers and field trials, have been conducted using 500 barley varieties from around the world.
We found that in both the glasshouse and the field, earlier-flowering genetics were successful strategies to mitigate heat damage and resulted in higher grain fertility, grain yield and grain quality traits.
Based on decreases in spikelet fertility at high temperature, cultivars Flinders , Vlamingh and La Trobe were most tolerant (two to six per cent reduction), while cultivars Grimmett and Oxford were highly susceptible (17 to 30 per cent reduction) and cultivars Sloop, Sloop Vic and Skiff and were moderately susceptible (eight to 13 per cent reduction) to high temperature.
The genetic material and molecular tools from both projects will provide new resources for breeding for best phenology adaptation, high grain yield, high spikelet fertility and improved heat tolerance.
Dr Camilla Hill, 0431 612 819, camilla.hill@murdoch.edu.au