Exploratory SSR-Based Assessment of Genetic Diversity and Differentiation Among Four Wild Almond Populations in Kazakhstan

Abstract

Wild almond relatives are valuable reservoirs of allelic variation for crop improvement and conservation, yet Kazakhstan’s wild-almond genetic resources remain poorly characterised. We conducted an exploratory SSR assessment of 80 putative individuals from four taxon-locality groups (20 per group), each representing one sampled population: Prunus ledebouriana, P. tenella, P. petunnikowii, and P. spinosissima. Of 22 nuclear simple sequence repeat loci screened for cross-taxon transferability, 15 generated reproducible profiles and were retained; their even genome-wide distribution was not verified. Across the full dataset, the mean number of alleles was 3.55, the effective number of alleles was 2.62, expected heterozygosity (He) was 0.544, and 95.0% of loci were polymorphic. Missing genotypes ranged from 0.0% to 34.7% among groups, and six loci had at least 20% missing data. AMOVA attributed 76.5% of variation to within-group differences and 23.5% to among-group differences (PhiPT = 0.235, p = 0.001). PCoA, unbiased Nei distances, UPGMA, and descriptive Bayesian clustering separated the four sampled groups. A nine-locus sensitivity analysis that excluded the six high-missing loci retained P. spinosissima as the group with the highest mean He (0.699), whereas P. petunnikowii increased from 0.471 to 0.609. Thus, the low full-panel estimate for P. petunnikowii was not robust to missing data. Because taxon identity was fully confounded with locality and the marker panel was limited, the results are interpreted as a regional marker-transferability and methodological baseline rather than as species-wide or genome-wide inference.