The use of the incompatibility S genotype in almond breeding for self‑compatibility is an useful tool as 100% of self‑compatible seedlings can be obtained by cross design, using the self‑compatible parent as male and having the female parent one allele in common. Thus choosing the crossing side is essential to raise all self‑compatible seedlings. In this work the results of two crosses between cultivars having one S₁ allele in common and being one of the parents self‑compatible are reported. Results of self‑compatibility in seedlings derived from these crosses, 'Masbovera' (S₁S₉) x 'Genco' (S₁S_f) and 'Falsa Barese' (S₁S_f) x 'Desmayo Largueta' (S₁S₅), are compared. Thirty‑one and 54 seedlings from each cross respectively were bagged in the field at flowering time to determine fruit set after selfing. All the seedlings were also analysed in the laboratory for stylar ribonucleases and zymograms were observed. Field results showed that almost 100% of the seedlings derived from 'Masbovera' x 'Genco' are self‑compatible as predicted and only about 50% of the seedlings derived from the cross 'Falsa Barese' x 'Desmayo Largueta' are self‑compatible. Stylar protein were extracted and separated electrophoretically using non‑equilibrium pH gradient electrofocusing (NEPHGE), and the polyacrylamide gels stained for ribonuclease activity revealing that all seedlings from 'Masbovera' x 'Genco' carry the S_f allele and only about the 50% of the seedlings from 'Falsa Barese' x 'Desmayo Largueta' are carrying the S_f allele. Both progenies gave self‑compatible seedlings although cross design could improve by doubling their yield choosing suitable parental combinations.