Genetic Diversity in Spanish and Foreign Almond Germplasm Assessed by Molecular Characterization with Simple Sequence Repeats

Abstract

<jats:p>Genetic diversity of the Spanish national almond (<jats:italic>Prunus amygdalus</jats:italic> Batsch) collection was characterized with 19 simple sequence repeat (SSR) markers selected because of their polymorphism in almond and other <jats:italic>Prunus</jats:italic> L. species. A total of 93 almond genotypes, including 63 Spanish cultivars from different growing regions, as well as some international cultivars and breeding releases were analyzed. All primers produced a successful amplification, giving a total of 323 fragments in the genotypes studied, with an average of 17 alleles per SSR, ranging from 4 (EPDCU5100) to 33 (BPPCT038). Allele size ranged from 88 bp at locus PMS40 to 260 bp at locus CPPCT022. The heterozygosity observed (0.72) was much higher not only than in other <jats:italic>Prunus</jats:italic> species, but also than in other almond pools already studied. The dendrogram generated using the variability observed classified most of the genotypes according to their geographical origin, confirming the particular evolution of different almond ecotypes. The SSR markers have consequently shown their usefulness for cultivar identification in almond, for establishing the genetic closeness among its cultivars, and for establishing genealogical relationships.</jats:p>

Identification of quantitative trait loci associated with self-compatibility in a Prunus species

“…Until recently, the movement of almond genotypes from one region to the other was limited. This fact, together with the traditional growing management in most almondgrowing regions, the consideration as a marginal fruit tree and the SI present in most cultivars, has produced a very polymorphic species (Fernández i Martí et al 2009b;Socias i Company and Felipe 1992). However, the advances in almond breeding, including as parent genotypes from different origins (Socias i Company et al 2010b) and also with a repeated utilization of related parents in the breeding programmes (Socias i Company 2002), may produce the interaction of genes so far isolated and the apparition of inbreeding depression (Alonso and Socias i Company 2007).…”

“…The female parent 'Vivot' is a SI Spanish local cultivar with the genotype S 23 S f , and the male parent 'Blanquerna' is a SC release from this programme with the genotype S 8 S f , obtained from a 'Genco' × 'AS-1' pollination (Fernández i Martí et al 2009b;. The trees are maintained as living plants in a nursery row using standard management practices.…”

“…A possible strategy for studying the genetics of the SI reaction was considered to be the analysis of the cosegregation between SI phenotypes and the SSR markers of a map constructed in an almond progeny showing an unexpected segregation for SI. SSRs are codominant, abundant (Gupta et al 1996), easily transferable to a large number of Prunus species (Mnejja et al 2010;Wünsch 2009) and extremely polymorphic, particularly in almond, which is one of the most polymorphic cultivated species within the Prunus genus (Byrne 1990;Fernández i Martí et al 2009b;Mnejja et al 2010;Socias i Company and Felipe 1992).…”

Molecular analyses of evolution and population structure in a worldwide almond [Prunus dulcis (Mill.) D.A. Webb syn. P. amygdalus Batsch] pool assessed by microsatellite markers

“…For fingerprinting and genetic diversity analysis, initially 33 sets of SSR primers were screened (Fernández i Martí et al 2009). Of these, 17 sets of fluorescently labelled SSR primers (PET, NED, VIC and 6-FAM) were subsequently used as they showed polymorphism at a single locus.…”

“…Simple sequence repeats (SSR) or microsatellite markers have been favored over other markers to establish unique genetic identities and to assess genetic diversity in almond (Fernández i Martí et al 2009). These markers are DNA segments containing short sequence repeats and are the preferred technique within crop species due to their abundance, codominance, high polymorphism and ease of use with the PCR conditions (Kuleung et al 2004).…”