Discovering novel genetic variation in height for hybrid wheat breeding
This project will be completed with the CASE partner, KWS UK LTD. Hybrid wheat holds great potential to increase wheat yields and yield stability in the coming years, ensuring crop production in the face of climate change. However, to breed successful hybrid varieties, additional genetic variation is required in a range of traits including plant height. The height of the female and male parents must be carefully controlled to maximise hybrid seed production and the resulting hybrids must have a height suitable for the target growing region, despite potential increases in height from heterosis.
In this project, we will identify novel genetic loci controlling plant height by focussing on single copy genes. Hexaploid bread wheat (Triticum aestivum) has on average three highly similar copies of every gene (homoeologs) which can be functionally redundant, i.e. if one homoeolog is mutated no phenotypic effect will be observed due to compensation by the other homoeologs. However, ~14% of the genes are single copy and do not have any homoeologs in hexaploid wheat. These single copy genes offer advantages to breeding to avoid genetic redundancy between homoeologs.
We recently cloned the Rht13 dwarfing gene which encodes a single copy gene and causes a comparable height reduction to the Green Revolution dwarfing genes Rht-B1b and Rht-D1b (Borrill et al., 2022, PNAS). We hypothesise that other single copy genes may affect height and that induced variation in these genes could be an important source of height modification for hybrid breeding. In this project we will deepen our understanding of how Rht13 reduces plant height and identify new single copy height genes that can be used in breeding hybrid wheat.
The student will develop a wide range of skills including plant genetics, molecular biology, gene editing and genomics. They will benefit from tailored training opportunities through the DTP programme and from the outstanding scientific environment across the NRP.
References
Borrill P, Mago R, Xu T, Ford B, Williams SJ, Derkx A, Bovill WD, Hyles J, Bhatt D, Xia X, MacMillan C, White R, Buss W, Molnár I, Walkowiak S, Olsen OA, Doležel J, Pozniak CJ, Spielmeyer W. 2022. An autoactive NB-LRR gene causes Rht13 dwarfism in wheat. PNAS: 119: e2209875119. https://doi.org/10.1073/pnas.2209875119
Borrill P, Harrington SA, Uauy C. 2019. Applying the latest advances in genomics and phenomics for trait discovery in polyploid wheat. Plant Journal 97: 56-72. https://doi.org/10.1111/tpj.14150
Borrill P. 2020. Blurring the boundaries between cereal crops and model plants. New Phytologist, 228: 1721. https://doi.org/10.1111/nph.16229.