EVALUATION OF NEW BLUEBERRY CULTIVARS IN PEDOCLIMATIC CONDITIONS FROM RIFG PITESTI-MARACINENI

Abstract

Vaccinum corymbosum is one of the species highly valued for the taste and dietary value of its berries. The new blueberry cultivars obtained in the breeding activity have high productivity, resistance to diseases and pests, and large and easily removable fruits. The success of the extension of blueberry crops depends on the adaptability of the cultivars to soil conditions and regional climate changes. A study was carried out at the Research Institute for Fruit Growing Pitesti-Maracineni, in the period 2019-2022, and was focused on the vegetative growth and fruiting processes, berries quality, and evaluated the disease and pest behavior of 13 new blueberry cultivars, currently in their 4th year ('Top Shelf', 'Blue Ribbon', 'Calypso' and 'Valor'), respectively 6 years from planting ('Duke', 'Bluejay', 'Draper', 'Liberty', 'Elliott' and 'Aurora'). The ripening period of the new cultivars covered a period between the second decade of June (12.06.2020, 'Duke') and the end of August (27.08.2021, 'Aurora', 'Last Call' and 'Elliott'). Depending on the age of fruit ripening, the cultivars were divided into very early ('Duke'), early ('Huron'), early-middle ('Blue Ribbon', 'Draper', 'Bluejay'), middle ('Top Shelf', 'Valor', 'Calypso'), late ('Cargo' and 'Liberty') and very late ('Last Call', 'Elliott' and 'Aurora'). At the end of the four years of study, the analysis of the data recorded for the vegetative growth and fruiting processes indicated that, for the younger plants (4th year after planting), for an average bush volume of 0.41m3 (0.14- 0.84 m3) berry yield fluctuated around 7.27 t/ha (1.66-16.59 t/ha). The cultivars with superior vigor were 'Valor', 'Last Call', and 'Cargo' (0.49-0.53 m3), the most productive being 'Cargo', with approximately 13.6 t /ha. For blueberry in the 6th year after planting, where the average volume of the bush was 0.53 m3 (0.19-0.82 m3), the fruit production was 6.89 t/ha (1.87 -14.4 t/ha). The cultivars with superior vigor were 'Bluejay', 'Aurora' and 'Liberty' (0.59-0.62 m3), and in terms of productivity, 'Duke' (9.13 t/ha) and 'Liberty' stood out (9.92 t/ha). For plants of the same age (3 and 4 years after planting), the average berry weight fluctuated around 2.25 g (0.7-5.72 g), the firmness recorded an average of 43.95 (15.9-77.50 units), while juice pH and total soluble substance content showed average values of 3.44 (2.24-5.72) and 13.32˚Brix (7.9-23.40). The highest berry weight was determined for 'Top Shelf' cultivar (2.9 g). The cultivars 'Aurora' and 'Last Call' stood out for their superior content of total soluble solids (17.14 and 16.01˚Brix), and the cultivars 'Blue Ribbon' and 'Top Shelf' for their high fruit pH (4.18 and 3.69). Last but not least, the high firmness of the fruits highlighted the Aurora and 'Blue Ribbon' cultivars (57.90 and 52.28 HPE-II-FFF Bareiss units). Regarding the phytosanitary status of the studied shrubs, increased sensitivity to diseases of the 'Huron' cultivar was highlighted (ISV 2.9%), especially to the attack of Phytophthora spp. (1.6%attack degree), which influenced significantly plant survival. At the end of the study period, we can recommend the cultivars 'Duke', Liberty', and 'Cargo' for cultivation in similar pedoclimatic conditions, the first standing out for its earliness and productivity, and the last two for their high fruit production.