Single-copy RAPD marker loci undetectable in octoploid strawberry

Random amplified polymorphic DNA (RAPD) was used to examine two selfed populations and two cross populations of octoploid strawberry obtained from two parents, cultivars Sachinoka and Cesena. The polymorphic bands of one parent appeared not only on the individuals of its selfed population, but also on the individuals of another parent's selfed population. In the selfed population of 'Cesena', the percentage of individuals presenting the polymorphic band of 'Sachinoka' was 10.3% to 41.4%, while in selfed population of 'Sachinoka', the percentage of individuals presenting the polymorphic band of Cesena was 13.8%. The result of experiments on an artificial mixture of DNA from two parents showed that polymorphism was never detected if DNA from 'Sachinoka' constituted a proportion of 0.3 or less. There was no change in the effect on polymorphic bands within the range of template DNA concentration in PCR reaction solution from 1 ng mul(-1) to 10 ng mul(-1). We concluded that single-copy RAPD marker loci are undetectable in octoploid strawberry because RAPD analysis is insensitive.