Improved discrimination of self-incompatibility S-RNase alleles in cherry and high throughput genotyping by automated sizing of first intron polymerase chain reaction products

A novel polymerase chain reaction (PCR) approach to determine and confirm the self-incompatibility (S) genotype of cherries is reported. The method involves PCR amplification with a new pair of consensus primers that immediately flank the first intron of cherry S-RNases, one of which is fluorescently labelled. Fluorescent amplification products range from 234 to c. 460 bp and can be sized accurately on an automated sequencer. Thirteen S alleles reported in sweet cherry can be distinguished, except for S-2 and S-7, which have an amplification product of exactly the same size. S-13, which is also amplified, gives a microsatellite-like trace which shows minor intra-allelic length variation. This method gives fast and accurate results and should be especially useful for medium/high-throughput genotyping of wild and cultivated cherries.