María Belén Díaz-Hernández

Morphology and microsatellites in Spanish apple collections

Summary The population of apple, Malus pumila Mill., indigenous to northwest Spain shows a wide range of ripening periods and fruit quality and is an unexploited resource for breeding programmes. The main purpose of this study was to fingerprint these accessions and to construct a molecular database including the cultivars commonly grown in Spain. A total of 77 indigenous and 26 international accessions were analysed using ten microsatellite [simple sequence repeat (SSR)] markers. Some of the main morphological and agronomic characteristics, such as fruit weight, colour, shape, sweetness in ºBrix, flavour type according to content of malic and tannic acids, and harvest time were recorded. The 77 Spanish cultivars showed a unique fingerprint. We propose to preserve these 77 genetically different cultivars in our Germplasm Bank, and recommend that 31 of them should be considered for a core collection to maintain all the diversity recorded. Some 29% of the cultivars showed three alleles at several loci and were confirmed, cytometrically, as triploids. These tended to produce larger fruit (15% by weight) than diploids. The use of ten polymorphic microsatellite markers provided a useful technique for fingerprinting apple cultivars in the Spanish germplasm resource and for indicating triploids. The fingerprints indicated that the famous triploid Dutch cultivar ‘Belle de Boskoop’ may be derived from an unreduced gamete of ‘Reinette de Caux’.

Database of European chestnut cultivars and definition of a core collection using simple sequence repeats

We have evaluated 271 accessions corresponding to 118 European cultivars, 96 from Spain, 16 from Italy, four from France and two from Portugal with the following objectives: (1) to provide a European database based on reference simple sequence repeats (SSRs) and (2) to define a core collection. A set of 24 highly polymorphic SSRs were used for the genetic analysis. Two main clusters were identified using a model-based Bayesian procedure, which correspond to Spanish and Italian cultivar clusters, with the latter showing a higher genetic diversity. An additional genetic substructure was observed among five different groups of cultivars. A core collection with a minimum of 37 cultivars was selected. We provided a database including 132 European accessions with unique genotypes evaluated with 24 SSRs as a reference for distinction, registering and traceability. Finally, we found that a core collection based on 14% of the total accessions conserves all allelic diversity.

Development of a standardized methodology for phenotypical characterizations in apple

4 Pags.- 2 Tabls. Articles derived from XIV EUCARPIA Symposium on Fruit Breeding and Genetics (Bologna,Italy. June 14-18 2015) . The definitive version is available at: http://www.actahort.org/index.htm