Identification of Self- incompatibility Alleles in Some Almond Genotypes by Degenerate S-RNase Primers

Abstract

The almond, <em>Prunus dulcis</em> Miller which belongs to Rosaceae family, is one of the most important commercial and oldest cultivated tree nut crops. Almonds are classified as a ‘nut' in which the edible seed is the commercial product. Therefore, pollination and fertilization are necessary in almond. The characteristic of cultivated almond to express gametophytic self- incompatibility discourages self-fertilization and favors cross pollination. Genetic control of pollen-pistil self-incompatibility is through a single gene (S) which exists in a series of alleles S₁ to S_x. Compatibility of pollen-pistil in almond is an important consideration in planning crosses in breeding program and in choosing pollinizers for orchard planting. Identification of self-(in) compatibility in almond carried out by molecular and controlled pollination methods. In this study, identification of S-alleles in 37 Iranian almond cultivars and genotypes was carried out by PCR method with using degenerate primers of EM-PC3consRDEMPC2cons FD, PaconsI-Fand EM-PC1consRD. In this way the size of S -alleles were estimated based on bands which amplified with second intron. The results confirmed self-incompatibility in cultivars and most genotypes. However, the S_f-like allele (in size) was observed in A₉ and A₃₆ genotypes. If these results are confirmed by sequencing the S_f allele, it will be first time to identify self-compatible genotype in Iranian almond genotypes.