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

Abstract

A total of 158 almond accessions representative of the diversity of almond across the five continents were included for analysis using 17 microsatellite polymorphic markers. Genetic relationships among genotypes were estimated using cluster analysis, allowing their differentiation in two main groups, one with the domesticated almond cultivars and selections and the other with all wild Prunus species close to almond. The unweighted pair group method average tree drawn from this analysis classified the genotypes according to their geographical origin, confirming the particular evolution of different almond ecotypes. Structure analysis showed a strong subpopulation structure and linkage disequilibrium decaying with increasing genetic linkage distance. Analysis of molecular variance confirmed that most of the genetic variability was within populations. Therefore the connection structure between the different populations and the possible bottlenecks in the expansion of almond cultivars could be established.

Genetic variability is preserved among strongly differentiated and geographically diverse almond germplasm: an assessment by simple sequence repeat markers

“…An AMOVA analysis declared that considerable genetic variation occurred within populations (71.30%), and genetic variation among populations was also significant, reaching a value of 28.70% (Table 4). This level of variation among populations is much higher than the value estimated for P. sibirica (Wang et al 2014) or P. mahaleb (Jordano and Godoy 2000), and that shown by Fernández i Martí et al (2015) in almond.…”

“…In general, H e values were higher than H o , and hence, the values of fixation index were positive for 14 primers and was only negative for one EST-SSR primer. The average F value was 0.13, which is lower than 0.23 reported by Fernández i Martí et al (2015). This low level of heterozygosis deficit is in harmony with the self-incompatibility of this species but it may indicate a modest level of inbreeding (discussed later).…”

“…Ukrainian almond breeding was based on a germplasm collection having accessions from France (Yezhov et al 2005) and several wild species (Gradziel 2011). The Nikitskyi clones were selected at the Nikita Botanical Garden of Yalta but they were reported to be introduced from France, which was also supported by clustering with Iranian and Mallorcan cultivars (Fernández i Martí et al 2015).…”

Comparative Study of Tocopherol Contents and Fatty Acids Composition in Twenty Almond Cultivars of Afghanistan

“…Almonds (Prunus dulcis, syn. Prunus amygdalus) originated in Central Asia, and now it is cultivated in the Mediterranean Basin, the Middle East, South-Western Asia, the USA, and Australia [1]. Globally, 1077,000 metric tons (MT; kernel basis) of almonds was produced (In season 2014/2015), in which, the United States of America alone shared 77.43%, followed by Australia (7.8%) and Spain (4.4%) [2].…”

Application of Genomic Technologies to the Breeding of Trees

“…In Prunus genus, introgressions from wild relatives resulted in gain for the commercial varieties, mainly concerning pathogen resistance (Quilot et al, 2004; Esmenjaud and Dirlewanger, 2007; Marandel et al, 2009). Other studies have focused on wild relatives from almond and apricot as a source of diversity (He et al, 2007; Zeinalabedini et al, 2008; Gross et al, 2012; Fernández i Martí et al, 2014). Increase in variability via wild relatives has been explored in other genera with relevant economic impacts such as Citrus (Barkley et al, 2006), and Olea (Belaj et al, 2010; Fernández i Martí et al, 2015a).…”