Assessment of the combining ability of selected forms of highbush blueberry (Vaccinium corymbosum) based on phenotypic evaluation of seedling progeny

Preliminary results on the general and specific combing ability (GCA and SCA) of selected parental forms of highbush blueberry (Vaccinium corymbosum) for the seedling’s growth are presented in this paper. The research material was the population of 2,100 F₁ generation seedlings obtained from the crossing program in 2014. Crosses including 12 parental cultivars (7♀ – ‘Aurora’, ‘Bluecrop’, ‘Brigitta Blue’, ‘Chandler’, ‘Draper’, ‘Duke’, ‘Northland’ and 5♂ – ‘Earliblue’, ‘KazPliszka’, ‘Polaris’, ‘Toro’, ‘Weymouth’) were done in a factorial cross-design (7×5). Seedlings belonging to 35 hybrid families were planted in the field, at the Pomological Orchard in Skierniewice, Central Poland in autumn 2014. The experiment was established in a complete random blocks design, in 4 replications, with 15 seedlings per plot. Studies on the growth of seedlings (measurement of plant height and width) was conducted in 2017-2018. It was shown that blueberry seedlings varied in strength of growth. Based on the results of the phenotypic evaluation of seedlings, the GCA effects for 12 parental cultivars and SCA effects for 35 hybrid families for the plant growth were estimated. It was found that tested parents differed in their combing ability for these morphological traits. Among the 12 highbush blueberry parental genotypes, the 6 cultivars had significant (positive or negative) GCA effects for the height and width of seedlings. Significant (positive or negative) SCA effects were estimated for 16 hybrid families among 35 tested. This means that these parental cultivars used in breeding programmes are donors of genes determining the strong growth (significant and positive) or poor growth (significant and negative values of these effects) of blueberry seedlings.