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Genetic diversity in two Italian almond collections
Rigoldi, Maria Pia; Rapposelli, Emma; De Giorgio, Donato; Resta, Paolo & Porceddu, Andrea
Abstract
Background: Sweet-seeded domesticated almonds were brought to the Mediterranean Basin from central Asia
about 4000 years ago. In Italy, most of the almonds produced are cultivated in the southern part of the
country. Local populations of the tree in Sardinia are largely seed-derived and mostly self-incompatible, so
have developed extensive genetic diversity. The need to protect biodiversity has prompted a revived interest
in local genetic materials in almond. Two Italian collections have been established, one in Sardinia and the
other in Apulia. These collections were the focus of the present evaluation of genetic diversity.
Results: Eleven SSRs (microsatellites) were used for fingerprinting. The Sardinian germplasm was highly
polymorphic, revealing a mean of 14.5 alleles per locus and a mean heterozygosity of 0.71. Using a
model-based clustering approach, two genetic clusters were distinguished: one included all the commercial
varieties and most of the Sardinian accessions, and the other most of the Apulian accessions. A similar
structure was produced using a distance-based cluster analysis. The Sardinian accessions could still be
distinguished from the commercial germplasm with few exceptions.
Conclusion: The extensive genetic variability present in the Sardinian and Apulian almond germplasm indicates
that these materials represent an important source of genes for the improvement of the crop.
Keywords
Biodiversity; Genetic structure; Prunus amygdalus; SSR
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