Pepper (Capsicum annuum L.) is one of the most valuable vegetables in the world. Over the last decades, highly performing cultivars have progressively replaced the diversified and heterogeneous landraces worldwide, causing wide genetic erosion in this crop. The recovery of these ancient landraces, which might preserve alleles of agricultural interest and local adaptations, results of pivotal importance for the development of new varieties and the maintenance of a sustainable agriculture. In the present work, a collection of twenty-six landrace-derived inbred lines and three landraces from NorthWest Spain were evaluated for their agronomic performance and genetic diversity based on a set of twenty-seven morphological descriptors and twenty microsatellite markers. The collection featured phenotypic variability for all the studied traits, which were influenced by the location, except for the yield. The principal component analysis divided the landraces in well-defined groups, with only Arnoia, Punxin and Blanco Rosal showing some degree of overlapping. The greater part of the variance was accounted for traits such as fruit weight, pericarp thickness and fruit shape and colour. The molecular analyses suggested a high level of genetic diversity within the collection and the presence of specific alleles, which were not previously detected in other Spanish pepper landraces. Multivariate and Bayesian clustering showed that landraces were primarily grouped according to their geographical origin and secondarily in agreement with the characteristics of their fruits. Six groups of landraces, with a great genetic differentiation, were clearly identified. Only the landraces Mougan and Arnoia possessed an allele associated to the pungency character.

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Fifteen onion landraces from Galicia (northwest Spain) were characterised with a set of 25 microsatellite markers and the genetic variability harboured by this collection was compared with the surrounding diversity by comparison with a representative panel of European onion landraces. Twenty markers were polymorphic allowing the detection of 121 alleles. Ninety-one of these were identified in the Galician group (average of 4.6 distinct alleles per locus) and 9% of the total number of alleles were recorded as unique alleles specifically contributed by onion landraces from northwest Spain. High values of observed and expected heterozygosities were detected for the majority of loci. Wright's fixation index confirmed an excess of heterozygotes and a low level of inbreeding, suggesting that high levels of heterogeneity have accumulated within landraces. Multivariate and STRUCTURE analyses revealed that Galician onions possessed a specific genomic composition different from that found in European landraces. ARTICLE HISTORY

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Conocer las preconcepciones del alumnado es clave para diseñar estrategias didácticas efectivas. En este estudio se examinaron estas preconcepciones en torno a biodiversidad, relaciones entre seres vivos y seres vivos y medio y la presencia de microorganismos en un ecosistema acuático (una ría), mediante un cuestionario cubierto por alumnado de 1º de ESO de un centro de Galicia. Los resultados muestran que muchas preconcepciones son compartidas con las descritas previamente para ecosistemas terrestres, aunque también hay algunas dificultades específicas. Además, el conocimiento mostrado sobre la biodiversidad de un ecosistema acuático próximo no es muy alto, induce a pensar que sería apropiado incluir en más profundidad este tipo de ecosistemas y aumentar la presencia del entorno cercano a la hora de tratar conceptos ecológicos. Así, el alumnado contará con más elementos conocidos con los que relacionar la información proporcionada en el aula.