Characterising and exploiting the Australian gene pool of Sorghum

Overview

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Crop wild relatives (CWR), including crop progenitors and other closely related taxa, have been beneficial to modern agriculture. These species provide plant breeders with a pool of genetic resources for introgression into domesticated varieties and are an important source of genetic diversity for crop improvement. Examples of CWR that have been exploited in commercial breeding programs include Aegilops tauschii and Oryza rufipogon that have been used to improve wheat and rice varieties, respectively.

During domestication, crop species are exposed to genetic bottlenecks that reduce genetic variation levels compared with wild progenitors. Low genetic diversity can make crops vulnerable to biotic and abiotic stresses and less able to adapt to changing environmental conditions. Consequently, CWR have been used in crop improvement for more than 100 years, especially for increasing resistance to insect pests and diseases.

The wild relative (Sorghum bicolor) of one domesticated grain crop species (Sorghum) in this respect have largely been ignored, even though non-domesticated Sorghum species offer a wealth of genetic variation with unique traits for stress resistance, yield and end-use quality.

The natural centre of diversity for the genus Sorghum is Australia, with 17 of the 25 recognised Sorghum species native to Australia (14 species are endemic to Australia). This native gene pool contains a number of species with novel endosperm structure, and adaptation to Australian climatic conditions that may be used to expand the cultivated gene pool via plant breeding. Recently, hybrids between S. bicolor and Australian Sorghum species, have been generated and now produce fertile F2 hybrids.

Although Australian native x domesticated sorghum hybrids have been generated, currently we do not understand whether introgression of native genes has occurred and whether introgressed genes underlie important agronomic traits in the Australian native Sorghum gene pool. Research validating the introgression of adaptive genes from native Sorghum species into the cultivated gene pool has lagged for two main reasons. First, because the native gene pool remains largely uncharacterised in terms of chromosome number (ploidy), genome content and composition. Second, the kind of genomic resources required to identify introgression of potentially important genes are not yet developed for any native Sorghum species.

Aims:

  • to characterise relationships in the genus Sorghum and quantify chromosome number and genome content variation in Australian Sorghum species
  • to generate genomic resources for Australian Sorghum species using exome sequencing
  • to characterize the extent of introgression from native Australian Sorghum species into the cultivated gene pool
Study level
PhD
Supervisors
QUT
Organisational unit

Science and Engineering Faculty

Research area

Biogeoscience

Keywords
sorghum, crops, agriculture
Contact
Please contact the supervisor.