Definición del núcleo optimizado de la colección de conservación del manzano español

5 Pags.- 1 Tabl.Este trabajo tiene como objetivo determinar la estrategia más adecuada para la selección del conjunto mínimo de accesiones (núcleo optimizado) que represente eficientemente la variación genética del manzano conservado en las colecciones españolas. Este núcleo optimizado mediante criterios genéticos constituirá la base de la colección nuclear de conservación, que podrá ser complementado con accesiones seleccionadas por otros criterios (morfo-fisiológicos, agronómicos, valor histórico, etc.). Se ha evaluado la eficiencia de estrategias de selección por búsqueda local estocástica avanzada (ASLS) que diferían tanto por el tamaño final del núcleo como por la combinación (y peso relativo) de las medidas de distancia genética y riqueza alélica a optimizar. Las estrategias empleadas han proporcionado núcleos optimizados con grandes diferencias en la diversidad conservada, así como en el nivel de representación de la estructura genética general. Teniendo en cuenta el uso principal de la colección nuclear, la estrategia que ofrece un mejor equilibrio entre representatividad y adecuación al uso es la que combina la optimización de la distancia media entre cada accesión de la colección y la entrada en el núcleo más cercana con el índice de Shannon y la recuperación de alelos.Este trabajo ha sido financiado por los proyectos INIA RF2011-00017-C05-00 y RTA2015-00052-C02-00Peer reviewe

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.htmThe description of phenotypic traits in apple cultivars is generally performed using internationally agreed descriptors such as UPOV guidelines, which defines for each trait several states of expression. However, it is not always possible to classify a cultivar unambiguously using those guidelines, because in practice the states are not clearly enough defined or the example cultivars are not always available in the collections. This work presents the results of a harmonization project performed by the teams responsible of the main apple germplasm collections in Spain. The objective was to develop a standardized method for the 57 traits included in the TG/14/9 UPOV guidelines for apple characterization, defining their states of expression in a clear and unambiguous way for Spanish germplasm. Phenotypic data collected for more than 1,600 accessions from Spanish collections were used and the method to define each state depended on the type of expression. For quantitative traits the number of states and their limits were defined according to the variability that exists within and between accessions. For qualitative traits, high-resolution images clearly depicting each state were selected. A standardized characterization protocol for the 57 traits of apple germplasm has been provided, enabling to comparing properly the phenotypes of Spanish genetic resources.This Project has been funded by the Spanish Ministry of Science and Innovation/National Institute for Agricultural and Food Research and Technology (RF2011- 00017-C05-00).Peer reviewe

Development of a standardized methodology for phenotypical characterizations in apple

1 pag.This work presents the results of a harmonization project performed by the teams responsible of the main apple germplasm collections in Spain. The objective was to develop a standardized method for the 57 traits included in the TG/14/9 UPOV guidelines for apple characterization, defining their states of expression in a clear and unambiguous way for Spanish germplasm.Peer reviewe

Analysis of the genetic diversity and structure of the Spanish apple genetic resources suggests the existence of an Iberian genepool

87 Pags.- 3 Tabls.- 5 Figs.- 1 Suppl. Fig.- 5 Suppl. Tabls. The definitive version is available at: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1744-7348The nature and structure of genetic diversity in the Spanish apple germplasm preserved at the national level was widely unknown, since studies performed to date on this topic have been exclusively carried out at the regional scale. Here, 1453 accessions from Spanish collections of Malus × domestica were evaluated with a common set of 13 SSR (Simple Sequence Repeats) markers in order to estimate genetic diversity, to identify the underlying genetic structure and to unravel the relationships among them and among a wide set of international cultivars for reference. In total, 737 unique genotypes were identified, 581 diploids and 156 triploids. Using a model-based Bayesian clustering procedure, two reconstructed populations were obtained for diploid genotypes; one retaining only Spanish cultivars (42% of genotypes), and a second containing all foreign cultivars the latter exhibiting evidence supporting the existence of a secondary sub-structure. Similarly, analysis performed on the 156 triploid genotypes also revealed two reconstructed populations; one exclusively associated with local Spanish genotypes (44%). The Jaccard coefficient allowed clustering by UPGMA (Unweighted Pair Group Method) diploid and triploid genotypes, and remarkable differences in allelic composition among the different partitioning levels were found. AMOVA analyses showed moderate but significant differentiation among the main groups (0.08 ≤ FST ≤ 0.12). Our results highlight an important fraction of the Spanish apple germplasm that constitutes a differentiated genepool with respect to the international and commercial apple cultivars. Moreover, the extent of the Spanish genetic diversity was spatially distributed along the northern Iberian Peninsula, suggesting an extensive migration of genotypes along the country. This study is the first valuable action for genetic conservation of apple at the national scale, and constitutes a decisive step towards the definition of a Spanish core collection that will be useful for further studies in dissecting the genetic control of important horticultural traits through genome-wide association analysis in apple.This work was supported by INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria), under the Project: 'Harmonization of the methodology of characterization, assessment of genetic diversity and definition of the core collection of the apple germplasm conserved in Spanish genebanks (ref. RF2011-00017-C05)'.Peer reviewe