Multivariate assessment of cultivars' biodiversity among the Polish strawberry core collection

The diversity of parental genotypes has a major impact on the progress of plant breeding. This study assessed phenotypic biodiversity of 91 strawberry genotypes in the core collection of the Research Institute of Horticulture in Skierniewice, Poland, using multivariate statistical methods. The assessment was carried out from 2008 through 2010 for 13 traits describing plant growth vigour, flowering and fruit ripening times, fruit yield, fruit appearance and quality (position of the calyx in relation to the surface of the fruit, fruit size and firmness, skin and flesh colour, fruit glossiness, intensity of the fruit's aroma and sweetness), as well as the genotypes' capacity for repeat-fruiting during the summer-autumn period. A principal component analysis using a hierarchical cluster analysis reduced the number of dimensions of more than a dozen traits describing the diversity of the assessed cultivars and identified six homogeneous groups, each consisting of cultivars with similar traits; this will simplify mate selection in the hybridization program and may reduce the size of the core collection.