Charles Sturt University
Graham Centre for Agricultural Innovation

Research investigates impact of cold temperature during seed formation

Charles Sturt University (CSU) research is investigating how cold temperature during seed formation in wheat impacts flowering time of the progeny crop.

CSU Bachelor of Science (Honours) student Mr Ramon Javier Atayde has been awarded a Graham Centre Honours Scholarship for his study.

Background

Mr Ramon Javier AtaydeTo avoid yield loss, grain growers aim to have wheat plants flowering under conditions that optimise grain formation, called the “flowering window’.

One of the key factors influencing the flowering time of winter wheats is vernalisation, or the accumulation of cold temperature.

Because wheat embryos are receptive to vernalisation as soon as they are active, there is evidence both anecdotally and in older literature to suggest that the developing embryo post anthesis can be partially vernalised whilst still attached to the mother plant. This could mean that progeny when sown, may be partially vernalised leading to plants flowering outside their optimum window and consequential yield loss due to cold stress.

Mr Atayde’s research aims to determine whether developing grains in wheat can be vernalised whilst still attached to the mother plant, and whether this translates to faster flowering of progeny once sown.

The research also aims to determine the extent at which developing grains respond to cold treatment. It is also investigating whether there are differences in receptiveness to cold treatment between wheat cultivars and NILS with differing genotypes, vernalisation and photoperiod requirements as determined by VRN-1 gene expression levels and timing of flowering.

The project

A parental population consisting of 12 wheat varieties with differing genotypes (9 NILS and 3 commercial winter wheats) has been established with 20-40 plants per variety. These have been grown to anthesis, with phenological measurements taken every second day. 14 days post anthesis, plants were then been placed in treatment chambers set to long (16hr @ 800ppf) days at a constant 4°C, where they will remain for the duration of their allocated treatment (0 (control), 3, 4, 5 or 6 weeks).

After this treatment the plants will be removed and embryos from the primary and secondary florets of the middle spikelet of the main stem will be excised and analysed for vrn-1 gene expression profiles using quantitative reverse transcriptase analysis at CSIRO.

Remaining seed from mother plants will then be allowed to mature for crown/ apex testing and re-sowing, with apical meristems also analysed for vrn-1 gene expression.

Re-sown progeny will be grown to elongation as a non-destructive way of determining the shift from vegetative to reproductive development, and compared to controls.

Mr Atayde’s research is supervised by CSU lecturer Dr Sergio Moroni, NSW Department of Primary Industries (DPI) crop physiologist Dr Felicity Harris and CSIRO research group leader Dr Ben Trevaskis.

Ramon Atayde (CSU) and Kerrie Ramm (CSIRO) inspecting developing grains in wheat mutants at CSIRO, Canberra.

“I have found my Honours to be challenging but rewarding, and have enjoyed the process,” Mr Atayde said.

“Often you forget how much effort goes on behind the scenes for research, and I feel like I have developed a new found appreciation for students that have completed higher study and researchers, particularly within agriculture.

“I have found the learning curve for Honours to be quite steep in some areas, which goes to show how much there is still to learn.  I look forward to the challenges the rest of my Honours project will present and the discoveries I hope to make in my research.

“I would like to thank the Graham Centre, my supervisors, and the staff at CSIRO, the Sutherland labs, viticulture centre and NALSH for their ongoing assistance and support.”

Contact: Ramon Atayde E: ratayde@csu.edu.au

 

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