Genetic pool structure of local apple cultivars from Portugal assessed by microsatellites

Abstract

A set of 87 apple accessions, located in three Portuguese apple germplasm collections, plus eight reference cultivars, were analyzed using 16 SSRs with the aim of assessing their genetic diversity and structure and evaluating relationships among them. Among the accessions studied, 64 unique genotypes were identified, 51 diploids and 13 putative triploids, revealing 19 groups of synonyms and 4 of homonyms. The genetic analyses performed by Bayesian modelbased clustering (Structure) revealed a clear differentiation of two major groups (RPP1 and RPP2), one of them (RPP1) corresponding to old local Portuguese accessions, some of them putatively derived from ancient hybridization with Reineta, and the second one (RPP2) including all reference accessions and local Portuguese accessions considered to be of more recent origin. These results were confirmed by factorial correspondence analysis (FCA) and molecular variance analysis (AMOVA) and are in accordance with the Jaccard coefficients. Results indicate that the Portuguese apple germplasm includes an important and distinct gene pool of cultivars with respect to reference international cultivars, being a relevant source of genetic diversity for present and future breeding programs, originated at least 200 years ago, when some of these cultivars were firstly named. Moreover, this study will be useful to improve the apple germplasm management and in the definition of a preservation strategy concerning the Portuguese apple landraces.

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

“…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). In contrast, the diversity observed here was lower than that observed in local cultivars of northeastern Spain (0.82) (Urrestarazu et al, 2012) and 0.80 (Pina et al, 2014), Italy (0.80) (Liang et al, 2015) and Portuguese Azores Islands, (0.81) (Foroni et al, 2012).…”

“…Primer pair ch01f02 showed the highest number of alleles (8 alleles), whereas primer pair28f4 had the lowest (3 alleles). The number of alleles per locus ranged from 3 to 8, suggesting moderate molecular genetic diversity between the apple cultivars studied (Ferreira et al, 2016).…”

Molecular markers useful to discriminate Coffea arabica cultivars with high genetic similarity

“…As an auxiliary alternative, the use of molecular descriptors has been widely discussed in the Working Group on Biochemical and Molecular Techniques (BMT) and DNA Profiling of the International Union for The Protection of New Varieties of Plants (UPOV 2010) in particular, and it is recommended for the identification, registration, and protection of new cultivars (Wang and Chuang 2013;Chen et al 2016). Molecular markers aid breeders in DUS testing of cultivars with a narrow genetic base (Ferreira et al 2016), and in the case of Coffea arabica, this strategy is especially useful (Ferrão et al 2015).…”

Apple (Malus spp.) Breeding: Present and Future

“…Heterozygosity in local cultivars was 0.75 in mainland Portugal (Ferreira et al 2016), about the same level of the American germplasm bank for Malus x domestica, 0.73 (Gross et al 2014), and slightly higher than the level of diversity found in Aragon-Spain, 0.68 (Pina et al 2014) but slightly lower than in north-eastern and north-western Spain, 0.80 and 0.83 respectively (Pereira-Lorenzo et al 2007;Urrestarazu et al 2012) and in Italy, 0.81 (Liang et al 2015), Portuguese Azores Islands, 0.82, (Foroni et al 2012), in in French germplasm (0.83) (Lassois et al 2016) and broad European apple germplasm (0.81) (Urrestarazu et al 2016).…”

“…Considering domesticated apples Malus x domestica, allelic diversity in genetic resources from mainland Portugal were reported as 11.5 alleles per locus (Ferreira et al 2016), similar to that reported in northwestern Spain (Galicia and Asturias) by Pereira-Lorenzo et al (2007) (11.4), to local germplasm from Aragon, northeastern Spain (12.4) (Pina et al 2014) in Iranian landraces (10.7) (Gharghani et al 2009), and for Sarajevo and eastern Bosnia accessions (13.5) (Gasi et al 2013), but lightly lower than those reported for the Portuguese Azores Islands apple germplasm (15.2 alleles/locus) (Foroni et al 2012), northeastern Spain (Aragon, Navarre, Basque Country, La Rioja and Catalonia regions) local material by Urrestarazu et al 2012) (16.7, for the local accessions of Italian apple germplasm maintained at Bologna (16.9) (Liang et al 2015), by Van Treuren et al (2010 in the Netherlands (18.5) and that found for whole Spain (18.6) (Pereira-Lorenzo et al 2017), for whole Europe (23.2) (Urrestarazu et al 2016) and in the American germplasm bank for Malus x domestica with 19.1 alleles per locus (Gross et al 2014).…”