The location and pattern of genetic recombination has important consequences for plant breeding and thus for how humans produce food effectively to supply a growing global population. Methods are being developed to increase recombination in breeding for domesticated crops, as there is concern that there is insufficient, particularly within peri-centromeric regions. Some care is however required: increased recombination in breeders’ germplasm can be disadvantageous if it breaks up favourable linkages previously built up over many generations of selection.
There are various methods by which rates and patterns of recombination can be altered, for example by heat treatment (Phillips et al., 2015). Additional cycles of crossing before selection are also effective. With the advent of ‘speed breeding’, these cycles can be accomplished cheaply and quickly for amenable crops. Targeting recombination to specific genomic intervals is also being studied (Ru and Bernardo, 2019), though the methods involved are currently further from practical application.
A consideration of how best to incorporate such technologies into practical breeding programmes involves computer simulations of approaches. This project will undertake these simulations and re-analyse existing datasets of wheat and barley, two crops of high importance to the UK and globally. The starting point will be to consider the consequences (time, cost, genetic gain) of additional cycles of crossing among inbred parents.
An alternative to targeted recombination is targeted non-recombination: if sufficient recombination is introduced into a population and if favourable linkage blocks are identifiable, non-recombinant blocks can be selected. This may be easier than targeted recombination and as a practical method it could be implemented now.
A major component of required research is to study the application of genetic markers, both to locate recombination and to identify favourable and disadvantageous linkage blocks. An important component of this PhD therefore will be to integrate genomic selection methods in breeding (Hickey et al., 2017). Approaches will be developed to identify favourable and disadvantageous haplotype blocks and integrate these into the selection process.
This PhD project will also model the incorporation into breeding programmes of the more advanced methods currently under development by JHI and others to increase the frequency of location-specific recombination. The consequences of introducing recombination into genomic regions where none has previously occurred cannot be studied empirically. However, knowledge of gene density, patterns of recombination and the location of genomic regions showing heterosis can be used to create realistic models of genetic architecture for this purpose.
The student will receive training in quantitative and statistical genetics at SRUC, together with a sound knowledge of plant breeding programmes and their design. Exposure to practical aspects of plant breeding: crossing, running field trials and genotyping, will be primarily through JHI. There will be opportunities to generate additional data on altered patterns of recombination in barley during the course of the PhD and the student will be given full opportunities to participate in these experiments. The student’s training will develop a crucial skill set for advancing UK and global food production.
Applicants should download the required forms from http://www.eastscotbiodtp.ac.uk/how-apply-0
and send the following documents to [email protected]
a. EASTBIO Application Form
b. EASTBIO DTP Equality Form
d. Academic transcripts (a minimum of an upper second class or first class honours degree or equivalent is required for PhD study
e. Two references should be provided by the deadline using the EASTBIO reference form (http://www.eastscotbiodtp.ac.uk/how-apply-0
). Please advise your referees to return the reference form to [email protected]
f. If you are nominated by the supervisor(s) of the EASTBIO PhD project you wish to apply for, they will provide a Supervisor Support Statement.