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 S2 and S7, which have an amplification product of exactly the same size. S13, 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.