Review and Update of Self-Incompatibility Alleles in Almond

Recent studies in local almond cultivars have allowed the identification of more S-alleles in almond (Prunus amygdalus Batsch). One hundred and sixty-two cultivars from different geographic origins have been reviewed in the present study and 31 self-incompatible S-alleles were compiled. The evaluation of fruit set and pollen tube growth in pistils in 24 cultivars has allowed the confirmation of two CIGs already identified (XVI and XVII) and the identification of five new ones (XXI-XXV). Thus, 27 cross-incompatible groups have been established. The study of local cultivars from different geographic origins may possibly increase the number of S alleles and CIGs in almond. The determination of the S genotype in almond cultivars and of cross-incompatibility groups is useful for grower cultivar choice when planting and for breeder design when planning crosses.