Locating genes for key traits in plants
Knowledge of the location of genes for important crop traits, such as yield, disease resistance, or crop timing, is crucial for breeding novel varieties that can be grown more efficiently and sustainably. Studies to locate genes rely on genetic maps of the chromosomes, where positions are identified by genetic markers such as Single Nucleotide Polymorphisms (SNPs). Markers close to genes for preferable traits can then be used to select favourable offspring during breeding, often years before the trait can be measured directly for the offspring.
Range of populations and traits
Some genetic populations are developed from inbred parents and have a simple structure. Others, especially those with a longer generation time such as fruit or trees, start from more diverse parents. Many plants have chromosomes in pairs, as mammals do, but some have chromosomes in sets of four, six, or more. These include key crops such as potato, wheat, and strawberry. Traits of interest may be simple measures such as yield, or processes such as fruit ripening stages.
BioSS has a long history of collaboration with geneticists to analyse genetic populations of plants. In particular, we have been involved in estimating high-density SNP maps for blackcurrant and raspberry, including developing computer software to do this more rapidly. We have devised statistical models for analysing traits related to processes such as fruit ripening, and for situations where the traits come from a field experiment followed by a laboratory process, such as measurements of amino acid levels.
For potato and similar crops with chromosomes in sets of four, we have created a software program, TetraploidSNPMap, which combines our theory of assembling genetic maps and locating genes with a user-friendly Windows interface.
Genetic markers that BioSS found close to genes for resistance to root rot in raspberry and gall mite in blackcurrant are now used in commercial fruit breeding. We have also located genes affecting raspberry ripening and resistance to the potato virus PVY.
BioSS is currently developing a network approach to look at measures of the chemical constituents of fruit and to study the genetics underpinning these.