Genetic markers are genes that produce a recognisable trait which, once identified, can allow the selection of certain attributes.
This leads to more rapid production of new varieties than conventional breeding, which works by crossing two parents that have the desired characteristics.
Conventional breeding can sometimes be a lottery as the recombination of genes during sexual reproduction can lead to many of the offspring being inferior.
SCRI's lead scientist for blackcurrant research Rex Brennan has been using genetic marking to breed new blackcurrant varieties resistant to gall mite, the vector of blackcurrant reversion virus.
He is also using genetic markers to boost the vitamin C content of blackcurrant juices, as the DNA marker for vitamin C has recently been identified. Blackcurrent juices like Ribena are a major source of antioxidants but commercial varieties vary enormously in their vitamin C content, with the lowest containing about 100g/100ml and the highest more than 400g/100ml.
In raspberries there are similar opportunities to link the quality of fruits to identifiable DNA markers to breed premium fruit.
Researcher Susan McCallum showed visitors examples of the diversity of berry colour in raspberries, with the aim of breeding for a red colour in the middle of the scale. This will become much easier as she identifies the genes involved.
McCallum predicted that DNA markers could cut the time to produce a new variety in half - which for raspberries might be a reduction from eight years to four - from first cross to finished variety.
Marker-assisted breeding could be used to improve flavour by identifying the genes for bitter and sour.