Discriminating ability of molecular markers and morphological characterization in the establishment of genetic relationships in cultivated genotypes of almond and related wild species

Abstract

A total 23 morphological traits, 19 AFLP-primer combinations, 80 RAPD primers and 32 SSR primer pair were used to compare the informativeness and efficiency of random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers in establishing genetic relationships among 29 almond cultivars and three related wild species. SSRs presented a high level of polymorphism and greater information content, as assessed by the expected hetrozygosity, compared to AFLPs and RAPDs. The lowest values of expected hetrozygosity were obtained for AFLPs; however AFLPs showed the highest efficiency, owing to their capacity to reveal large numbers of bands per reaction, which led to high values for various types of indices of diversity. All the three techniques discriminated almond genotypes very effectively, except that SSRs failed to discriminate between 'Monagha' and 'Sefied' almond genotypes. The correlation coefficients of similarity were statistically significant for all the three marker systems, but were lower for the SSR data than for RAPDs and AFLPs. For all the markers, high similarity in dendrogram topologies was obtained, although some differences were observed. All the dendrograms, including that obtained by the combined use of all the marker data, reflect relationships for most of cultivars according to their geographic diffusion. AMOVA detected more variation among cultivated and related wild species of almond within each geographic group. Bootstrap analysis revealed that the number of markers used was sufficient for reliable estimation of genetic similarity and for meaningful comparisons of marker types.

Morphological and molecular variability in some Iranian almond genotypes and related Prunus species and their potentials for rootstock breeding

“…RAPD approach has been used to study the genetic diversity of almond germplasm in several studies (Casas et al, 1999;Mir Ali and Nabulsi, 2003;Shiran et al, 2007) and also has been shown to be a reliable marker with a series of advantages such as performing quick, number of arbitrary primers (Baránek et al, 2006;Shiran et al, 2007;Sorkheh et al, 2009a). Our results also showed that RAPD marker could properly detected the similarity in the studied plant materials.…”

“…Random amplified polymorphic DNA (RAPD) technique has been used to study the genetic diversity of Prunus, including almonds, in several studies (Gogorcena et al, 1993;Casas et al, 1999;Mir Ali and Nabulsi, 2003;Gouta et al, 2008;Shiran et al, 2007) and is considered as a quick, inexpensive and less laborious approach for studying genetic diversity. Previous studies showed that results of RAPD analysis are reliable and comparable to markers like SSR (Baránek et al, 2006;Shiran et al, 2007;Bouhadida et al, 2009;Gouta et al, 2010) and AFLP (Sorkheh et al, 2009a).…”

“…In the studies of genetic diversity, the combination of the necessary and also less laborious morphological evaluation with molecular markers leads to more reliable conclusions in the assessment of genetic diversity. (Sorkheh et al, 2007;Khadivi-khub et al, 2008;Hend et al, 2009;Sorkheh et al, 2009a).…”

“…Previous authors have determined genetic relationships and diversity in almond using different kinds of markers such as isoenzyme (Vezvaei, 2003), SSRs (Shiran et al, 2007;Zeinalabedini et al, 2008), AFLPs (Sorkheh et al, 2007(Sorkheh et al, , 2009a and morphological traits (Sorkheh, 2009b). This is possibly the first study conducted on the Iranian almond germplasm w i t h r e g a r d t o rootstock breeding point of view using both morphological and molecular techniques.…”

“…A few studies have conducted on the assessment of genetic diversity and relationships among Iranian cultivated and wild almond genotypes with regard to molecular and morphological analyses (Zeinalabedini et al, 2008;Sorkheh et al, 2007;2009a). In other words, ongoing researches on Iranian Almond germplasm are increasing our knowledge about the morphological/molecular duality in these valuable and closely related plant materials.…”