Multidimensional analysis of S-alleles from cross-incompatible groups of California almond cultivars

Abstract

The California almond industry is the largest supplier of almonds [Prunus dulcis (Miller) D.A. Webb] in the United States and throughout the world. Self-incompatibility is a major issue in almond production as it greatly affects nut set. In this study, we determined full-length sequences for alleles S a - Si, determined the genotypes of 44 California cultivars, and assigned the cultivars to cross-incompatibility groups (CIGs). Newly identified S-alleles led to an increase in the number of CIGs. A pairwise distance tree was constructed using the aligned amino acid sequences showing their similarity. Four pairs of alleles (Sc and Se S g and Sh, Sd and Si, and S b and Sf) showed high sequence similarity. Because of its simplicity, reproducibility, and ease of analysis, PCR is the preferred method for genotyping S-alleles.