Ryan Whitford

The FAO predicts that major improvements in wheat yields will be critical to ensuring global food security (FAO, 2013). Over the past decade, wheat yield improvements from conventional crop breeding has tapered off. This stands in contrast to the situation in rice and maize where yield improvements have continued unabated. Several reasons have been proposed for this difference between maize and wheat:

1. increased private sector investment in maize research
2. early adoption and implementation of GM technologies
3. increased opportunities provided by hybrid breeding.

Hybrid wheats hold the potential to increase yields and will open a range of new breeding opportunities. Although capturing heterosis in wheat has historically been intractable, a recent experimental survey of European winter wheat combining ability indicates yield gains of 10% can be achieved (HYWHEAT consortium, Longin et al., 2013). Commercial exploitation of this heterotic yield gain is likely to be difficult due to wheat’s strong inbreeding nature, a factor primarily governed by floral development and architecture, and the lack of a cost-effective and practicable fertility control system (Whitford et al., 2013). The aim of ACPFG’s Hybrid Wheat Research team is to reduce hybrid seed production costs by

1. Developing a robust male sterility and restoration system, and
2. Improving wheat’s floral characteristics for out-crossing

Project Title: Developing a fertility restoration system for hybrid wheat seed production

Project Partner: DuPont-Pioneer

The fertility control team is responsible for identifying novel gene sequences necessary for wheat fertility. The program exploits mutant resources by next generation sequencing and the latest bioinformatic analyses in a forward genetics approach towards gene identification. Reverse genetics techniques including mutant complementation and genome editing (CRISPR/cas9) are used to validate which fine-mapped gene sequences are necessary for ensuring fertility. Fertility genes and their encoded proteins are typically characterised at the transcriptomic, proteomic and metabolomics levels relative to their specific roles in reproductive development.

Techniques 

• Positional cloning
• Molecular markers
• Genotyping by Sequencing (GbS)
• Genome Wide Association Study (GWAS)
• RNAseq/qRT-PCR
• Quantitative PCR
• Cloning/Vector construction
• GC-MS-based metabolite profiling
• Light and confocal microscopy
• SEM, TEM
• Phenotypic analyses on floral and reproductive development
• Glasshouse and field work
• Biolistic and Agrobacterium mediated transformation
• Genome editing

References

• FAOSTAT (2013) http://faostat3.fao.org/home/index.html
• Longin CFH, Gowda M, Mühleisen J, Ebmeyer E, Kazman E, Schachschnieder R, Schacht J, Kirchhoff M, Zhao Y, Reif JC.(2013) Hybrid wheat: quantitative genetic parameters and consequences for the design of breeding programs. Theoretical and Applied Genetics doi 10.1007/s00122-013-2177-z.
• Whitford, R., Fleury, D., Reif, J.C., Garcia, M., Okada, T., Korzun, V., and Langridge, P. (2013) Hybrid breeding in wheat: technologies to improve hybrid wheat seed production. Journal of Experimental Botany (Darwin Review) DOI: 10.1093/jxb/ert333.