|Authors: ||J. Urrestarazu, M.J. Laquidáin, C. Miranda, L.G. Santesteban , J.B. Royo|
|Keywords: ||microsatellite, SSR, genetic diversity, apple cultivars, Malus × domestica|
Since the 1960s, a few major cultivars (from ‘Golden’, ‘Gala’, ‘Red Delicious’ or ‘Fuji’ groups or derived from them) have drastically replaced the pool of ancient traditional and well-adapted cultivars on which apple production was based earlier in Spain.
As a consequence, many traditional or local cultivars have been considered to be “obsolete”, leading to a dramatic loss of genetic diversity.
The objective of this study is to assess and compare the variability and diversity contained within three apple collections curated in northeastern Spain, namely in the Germplasm Banks at Universidad Pública de Navarra (UPNA, Pamplona), Estación Experimental de Aula Dei (EEAD, Zaragoza) and Universidad de Lleida (UdL, Lleida), previously finger-printed with a common set of 9 SSRs.
Diversity assessment was performed using: number of alleles (total and effective) per locus, allele frequencies, heterozygosities and Nei (DI) and Shannon-Weaver (H’c) diversity indexes.
Genetic relationships among the genotypes were calculated using cluster and molecular variance analyses.
The three collections preserve high genetic diversity (DI>0.8, H’c>1.8 and a mean of ≈10 alleles/locus). Multivariate cluster analysis showed the presence of an important core group where most accessions (≈80%) were included, and also other smaller groups, mainly made up of accessions from a single collection.
AMOVA analysis showed highly significant, although small (FST=0.017), variance differences among the three collections.
Download Adobe Acrobat Reader (free software to read PDF files)