Agro-morphological diversity of local and international accessions of the Spanish Pear Germplasm Bank in Zaragoza

A set of 34 landraces and local accessions and 39 international reference cultivars from the Spanish Pear Germplasm Bank in Zaragoza (Spain) was agro-morphologically characterized based on 50 Bioversity International and UPOV descriptors (24 quantitative and 26 qualitative) in order to evaluate the agro-morphological variability of the Spanish germplasm, identify the most relevant differences with the international reference cultivars and group the accessions according to their agro-morphological distances. The correlation analysis between the 24 quantitative descriptors revealed few significant correlations, four positive ('leaf blade length'-'leaf blade width', 'season of ripening'-' fruit size', 'russet around eye basin'-'russet on cheeks' and 'russet on cheeks'-'russet around stalk') and one negative ('leaf blade width'-'ratio length/with'). The traits showing the highest phenotypic variability were 'fruit size', 'fruit firmness', 'fruit acidity', 'leaf distance from the stipules to the petiole base' and 'length of leaf pointed tip'. As a whole, the Spanish accessions were more precocious in flowering and ripening time than the international reference group, showed a bigger flower petal size, a smaller fruit size, a more rounded fruit shape, less incidence of skin russet and more 'spreading' fruit attitude of sepals. The dendrogram obtained from the agromorphological distances do not group the accessions according to their geographical origin; nevertheless, a small group of seven Spanish cultivars ('Don Guindo', 'L-3.2.10', 'Duquesa Barreda', 'Limon de Verano', 'Malacara', 'Tocinera' and 'Magallon') showed a higher distance to the rest of accessions included in the study.