Genetic diversity and core collection of Malus × domestica in northwestern Spain, Portugal and the Canary Islands by SSRs

• Published in: Scientia horticulturae 2018-10, Vol.240, p.49-56
• Main Authors: Pereira-Lorenzo, Santiago, Ramos-Cabrer, Ana María, Ferreira, Vanessa, Díaz-Hernández, María Belén, Carnide, Valdemar, Pinto-Carnide, Olinda, Rodrigues, Raúl, Velázquez-Barrera, María Encarnación, Rios-Mesa, Domingo, Ascasíbar-Errasti, Javier, Castro, Isaura
• Format: Article
• Language: English
• Subjects: Apple; Germplasm banks; Local cultivars; Molecular markers; Structure; Variability
• ISSN: 0304-4238; 1879-1018
• DOI: 10.1016/j.scienta.2018.05.053

•634 apple accessions from western Spain and Portugal were studied using 13 SSRs.•Two reconstructed panmictic populations were identified, the first included only local varieties.•29 new synonyms were found between Galicia and the Canary Islands (2000 km apart).•Main varietal groups: Pero, Camoesa, Repinaldo, Reineta, Tres en Cunca, Rayada, Torres Agrelo.•A core collection was defined keeping 17% of the accessions. The domesticated apple (Malus × domestica Borkh.) is one of the most relevant cultivated fruit crops worldwide, in particular in temperate zones, and the fourth most economically important. In order to avoid loss of genetic diversity, germplasm banks have been established to conserve proper genetic diversity, among them we have evaluated five that covers western Iberian Peninsula (the one from Galicia and three from northern to southern Portugal) and Canary Islands.A total of 634 accessions composed of old and local autochthonous apple germplasm, as well as commercial and reference varieties, plus 16 accessions that were collected as wild apples, were studied. Of the total, 484 local accessions were obtained from Spain and 67 from Portugal. The objective of the present study was to analyse the genetic diversity and genetic structure, and define core collection (a small group of cultivars that preserve the allele diversity of the set), by using 13 microsatellite markers (SSRs). Of the total of 634 accessions studied, corresponding to 370 unique genotypes, were grouped into two reconstructed panmictic populations or RPPs; the first RPP included 506 accessions (304 unique genotypes), which belonged to local and autochthonous varieties; and the second RPP clustered the remaining 128 (66 distinct genotypes), which were commercial and reference varieties. In total, 29 new synonyms (74 accessions) were identified between Galicia and the Canary Islands, which indicated the close historical relationship between these two regions located 2000 km apart. A core collection to preserve the whole allelic diversity of the west of the Iberian Peninsula (Galicia and Portugal) and the Canary Islands was defined keeping 10% of the genotypes (63) with respect to total accessions of the complete study, 14% of them (54) from Galicia with wild accessions or 15% (55) from Galicia without wild accessions, 40% (30) from the Canary Islands and 36% (24) from Portugal. The results obtained will allow update of the germplasm banks with correct identification of cultivars, dif