Re-examination of (in)compatibility genotypes of two John Innes self-compatible sweet cherry selections

The (in)compatibility genotypes of two selfcompatible sweet cherry selectio ns, JI 2420 and JI 2434, originating from the John Innes Institute were re- examined. The selections and seedlings derived from them were analysed for stylar ribonucleases, which are known to correlate with S alleles, and the outcome of test crosses was recorded. JI 2420, which had been reported prev iously as S3S4' where ' indicates loss of pollen activity, was deduced to h ave the genotype S4S4'. For JI 2434, which had been reported previously as S3S40, S3S30 or S3S3' where (0) indicates loss of pollen and stylar activit y, two different clones were identified. One, at East Malling, was deduced to be S-3'S-4; the other, at Ahrensburg, appeared to be S3S3' or S3S30.