It had been demonstrated previously at East Malling that the various incompatibility (S) alleles of almond cultivars correlate with the stylar ribonucleases revealed electrophoretically. This work showed that 'Desmayo Largueta', an old Spanish cultivar, and 'Glorieta', a cultivar bred at Mas Bové, neither of which had previously been genotyped, have the same pattern of stylar ribonucleases as the French 'Languedoc' and the American cultivar 'Texas'. To check the hypothesis that these cultivars have the same S genotype, test crosses were made; two at Mas Bové, 'Glorieta' x 'Desmayo Largueta' and 'Texas' x 'Glorieta', and one at Avignon, 'Glorieta' x 'Texas', in addition to 'Texas' x 'Languedoc' which was known to be incompatible. No fruit was set. This incompatibility suggests that 'Desmayo Largueta' and 'Glorieta' indeed have the same S genotype as 'Texas' and 'Languedoc', which was formerly designated SaSb, and is now relabelled S1S5. This work validates the practical use of stylar ribonuclease analysis for predicting incompatibility alleles of almond cultivars.