Genetic diversity in apricot revealed by AFLP markers: species and cultivar comparisons

Abstract

The genetic diversity of apricot ( Prunus armeniaca; 2n = 16) was studied using AFLP markers. Forty seven apricot cultivars were selected from the following geographic regions: Europe, North America, North Africa, Turkey, Iran and China. Five EcoRI- MseI AFLP primer combinations revealed 416 legible bands, of which 379 were polymorphic markers. A similarity matrix was prepared using the simple matching coefficient of similarity. A UPGMA dendrogram demonstrated a gradient of decreasing genetic diversity of varieties from the former USSR to Southern Europe. This is coherent with the historical dissemination of apricot from its center of origin in Asia. The American cultivars were intermediate demonstrating a different genetic base than the European and/or Mediterranean cultivars. Euclidean distances from the first ten Factorial Component Analysis coordinate axes were used to generate a tree using the Ward algorithm. The results of these analyses were evaluated based on the known geographic origins and agronomic characteristics of the cultivars studied. Four cultivar groups were identified: Diversification, Geographically Adaptable, Continental Europe and Mediterranean Basin. To evaluate the relationship of the common apricot with some closely related species, one or two accessions of the following related species or sub-species from within the section Armeniaca were included in the analysis: Prunus armeniaca var. ansu, Prunus mume, Prunus brigantiaca, Prunus dasycarpa, and Prunus holosericea. A Neighbour Joining dendrogram was made using the similarity matrix. The P. holosericea accession fell well within the cultivar group, thus supporting its classification as a variant of P. armeniaca. The P. armeniaca var. ansu accession was sister to the common apricot cluster with a bootstrap value of 96%. P. mume was farther removed. P. brigantiaca was the most-distant from the common apricots. P. dasycarpa was intermediate between P. brigantiaca and P. mume, in accord with its plum-apricot hybrid origin. The results have a direct application for the selection of new breeding progenitors.

Genetic linkage maps of two apricot cultivars (Prunus armeniaca L.) compared with the almond Texas × peach Earlygold reference map for Prunus

“…The difference in heterozygosity observed with both techniques is in agreement with the known geographical origin of the cultivars. As reported by Hagen et al (2002), Stark Early Orange belongs to the Diversification group that includes cultivars from former USSR and Central Asia. These are characterized by a large variability for most agronomical traits, heavy chill requirements and late flowering.…”

“…Apricot diversity has been studied using isozymes (Byrne and Littleton 1989), restriction fragment length polymorphisms (RFLPs) and amplified fragment length polymorphisms (AFLPs) (Hagen et al 2002). Two genetic linkage maps of apricot have been published (Hurtado et al 2002;Vilanova et al 2003).…”

Phenotypic diversity and relationships of fruit quality traits in apricot (Prunus armeniaca L.) germplasm

“…An important genetic diversity has been observed in the apricot species regarding some quality parameters studied, fundamentally due to the different genetic origins of the cultivated apricot cultivars (Byrne and Littleton 1989;Mehlenbacher et al 1991;Audergon et al 1991;Ledbetter et al 1996;Badenes et al 1998;Hagen et al 2002;Hormaza 2002;Asma and Ozturk 2005). On the other hand, several reports on peach have shown an important effect of the year on some pomological traits, due to the different climatic conditions (temperature, solar radiation, rainfall, etc.)…”

Application of the TRAP technique to lettuce (Lactuca sativa L.) genotyping

“…DNA-based molecular markers have become the tool of choice for crop genetic diversity assessment (Pujar et al, 1999;Hagen et al, 2002). Genetic variability is very important to a given crop because it is directly related to genetic vulnerability and the potential for genetic improvement.…”