Correlation of ribonuclease zymograms and incompatibility genotypes in almond

Proteins were extracted from styles of 29 self-incompatible cultivars of almond and separated using non-equilibrium pH gradient electro-focusing, and the gels were stained for ribonuclease activity. Mutually incompatible cultivars had similar banding patterns and, for the 24 cultivars already genotyped in France or California, the bands correlated well with the reported alleles. The band corresponding to S₁ of the French labelling system was indistinguishable from that corresponding to S_b of the Californian labelling system, and a controlled cross confirmed that these alleles are identical. The band corresponding to the Californian S_a was distinct from the bands corresponding to French alleles and, to harmonise the allele labels, it was redesignated S₅. The genotypes of five uncharacterised self-incompatible cultivars were inferred from zymograms as follows: ‘Desmayo Largueta’ and ‘Glorieta’, S₁S₅, ‘Masbovera’, S₁S₉, ‘Tarragones’, S₂S₉, and ‘Tokyo’, S₆S₇. The alleles designated S₆ and S₉ have not previously been reported. Nine self-compatible cultivars or selections were analysed, and each showed a band corresponding to an incompatibility allele as well as a common band; however, the correspondence of this common band to S_f, the allele for self-compatibility, is unproven. This revised version was published online in July 2006 with corrections to the Cover Date.