Genetic identity and relationships of Iranian apple (Malus × domestica Borkh.) cultivars and landraces, wild Malus species and representative old apple cultivars based on simple sequence repeat (SSR) marker analysis

Abstract

In order to shed light on the role of Iran in apple evolution and domestication, we chose to investigate the relationships of a collection of 159 accessions of wild and domesticated apples including Iranian indigenous apple cultivars and landraces, selected wild species, and old apple scion and rootstock cultivars from different parts of the world. The majority of the wild species belonged to M. sieversii, which is widely believed to be the main maternal wild ancestor of domestic apples, from Kazakhstan and M. orientalis, which is one of the probable minor ancestors of domestic apples, from Turkey and Russia located on the east and west of Iran, respectively. The accessions were assigned into six arbitrary populations for the purpose of generating information on genetic parameters. Nine simple sequence repeat (SSR) loci selected from previous studies in apple were screened over DNA extracted from all the accessions. Results showed that all SSR loci displayed a very high degree of polymorphism with 11-25 alleles per locus. In total, there were 153 alleles across all loci with an average of 17 alleles per locus. The SSR allelic data were then used for estimation of population genetic parameters, including genetic variation statistics, F-statistics, gene flow,genetic identity, genetic distance and then cluster analysis using POPGENE 1.32 software. The F-statistics and gene flow in particular, showed that there was more intra-population than between population variation. The genetic identity and genetic distance estimates, and the dendrogram generated from the un-weighted pair group arithmetic average (UPGMA) method of cluster analysis showed that the Iranian cultivars and landraces were more closely related to M. sieversii from Central Asia (east of Iran) and M. orientalis native to Turkey and Russia than to other accessions of Malus species. Also, the old apple cultivars from different parts of the world have a closer genetic relationship to M. sieversii, M. orientalis and the Iranian apples, than to other wild species. Based on these results, we suggest that the Iranian apples may occupy an intermediate position between the

The genome of the domesticated apple (Malus × domestica Borkh.)

“…The already known 42,43 genetic similarity of M. sieversii to M. orientalis and to M. × asiatica (a Chinese cultivated apple form) is also confirmed by our data.…”

Phenotypic and molecular characterization of apple (Malus × domestica Borkh) genetic resources in Greece

“…Furthermore, the Shannon's information index (I) maximum (1.620) was recorded for ch01f02, while the lowest value (1.299) was recorded for locus 28f4, with an average of 1.335. Our results revealed a decreased number of alleles per locus than those reported previously for apple (Gharghani et al, 2009;Liang et al, 2015;Urrestarazu et al, 2012), which could be attributed to the smaller number of cultivars tested in our study. Moreover, the diversity level of heterozygosity in our collection (0.627) is slightly lower compared with heterozygosity (0.73) described for apples from the regions of Asturias, the Basque Country, and Galicia in northern and northwestern Spain (Pereira-Lorenzo et al, 2003) and 0.75 in Portuguese apple germplasm collections (Ferreira et al, 2016).…”

Microsatellite genotyping of apple (Malus × domestica Borkh.) genetic resources in the Netherlands: application in collection management and variety identification

“…M. Roemer, are thought to form the ancestors of cultivated apple, although the genetic background of apple is still not fully understood (Janick et al 1996;Gharghani et al 2009). Cultivated apple is generally believed to have its centre of diversity and domestication in Central Asia, from which it has spread in various directions (Gharghani et al 2009). Apple cultivation in Southern Europe dates back to prehistoric times.…”

“…In apple, microsatellites are usually found to be highly polymorphic and, thus, have proven to be a powerful marker system for diversity studies (Hokanson et al 2001;Coart et al 2003;Gharghani et al 2009) and for variety discrimination (Guilford et al 1997;Hokanson et al 1998;Goulão and Oliveira 2001). Microsatellites have also been used to monitor variation in genes for important traits, such as resistance to apple scab (Vinatzer et al 2004).…”