Recently, there has been a trend towards healthy food. Consumers are looking for products that have health-promoting properties in addition to their taste. Actinidia fruit, apart from being tasty, contains valuable macro and micronutrients, vitamins, polyphenols and pectins. Tested cultivar Sientiabrskaja belong to Actinidia arguta and cultivars Geneva, Issai and Ken’s Red to A. kolomitka. They well tolerate conditions of moderate climate with negative temperatures in winter. To improve fruit quality, an additional summer pruning of the plants was performed at the time of ripening. After the second additional cutting of Actinidia shoots, an increase in the content of N, P and K in fruit was observed. The additional pruning also had a beneficial effect on the change in fruit color. The fruits were darker, especially in the cultivars Geneva and Ken’s Red. This is related to the ripening of fruit and an increase in anthocyanin content. Additional summer pruning caused changes in the polyphenol content-the amount of phenolic acid and flavan-3 ols decreased, while the level of anthocyanins increased. The antioxidant capacity also increased as well as fruit size, dry matter, pectin and Soluble Solid Content (SSC) content. The acidity of the fruit also decreased which positively affects the taste of the fruit. The highest content of polyphenols and L-ascorbic acid was found in ‘Sientiabrskaja’ fruit; but the highest antioxidant activity (determined Free Radical Diphenylpicrylhydrazyl-DPPH•, ABTS•+ and Ferric Antioxidant Power-FRAP) was found in fruit with red skin coloring and anthocyanins-‘Issai’ and ‘Ken’s Red’.

AbstractA significant increase in highbush blueberry plantings has been observed annually. However, there is a problem with the handling of fruit that does not meet the requirements for dessert berries. One of the methods to use the fruit is drying. The research was conducted in the Department of Horticulture at the West Pomeranian University of Technology in Szczecin. The fruit was harvested at a plantation specialising in the production of highbush blueberry from irrigated and non-irrigated plots. This study aimed to assess how cutting or pricking highbush blueberry fruit affects the duration of the sublimation drying process – freeze-drying. The biological value of fresh, freeze-dried, and rehydrated fruit was assessed. The amount of fruit left on bushes depended on the weather prevailing in the growing season, especially during the harvest period. The mass of fruit left on the bushes was approx. 1 to 2 t/ha. Although these fruits were small, they had a very high biological value. After freeze-drying and rehydration, the blueberry fruit retained their colour, high content of polyphenols and showed high antidiabetic activity and antioxidant capacity. The large fruit reached the moisture content of approx. 12%, which ensures safe storage and the appropriate texture, after 46 hours of drying, and the smaller fruit - after 32 hours. Fruit cutting or pricking reduced the drying time by half. Reducing this time decreased drying costs and increased biological value.

Highbush blueberry (Vaccinium corymbosum L.) is increasingly farmed for its nutritional and health benefits, but high yield and fruit quality require proper planting material. Modified Murashige and Skoog (MW), Anderson’s Rhododendron (AN), and Woody Plant Medium (WPM) were compared for in vitro organogenesis and rooting of three highbush blueberries ‘Elizabeth’, ‘Meader’, and ‘Liberty’. All media contained 0.1 mg L-1 zeatin applied with a combination of IBA, IAA, and GA3. The results showed that MW medium is more suitable for in vitro multiplication of ‘Elizabeth’ and ‘Meader’, and WPM medium for ‘Liberty’. However, medium supplemented with a low concentration of IBA (≤ 0.4 mg L-1) and 0.1 mg L-1 zeatin increased the shoot regeneration rate of highbush blueberries multiplied in vitro. The rooting capability was studied by using WPM and AN medium with IBA and IAA with zeatin. The highest rooting rate (85%) and acclimatization (70%) were achieved in ‘Liberty’, and the lowest was in ‘Elizabeth’ (33.3% and 50%, respectively) and ‘Meader’ (33.3% and 43.8%, respectively). Rooted plantlets developed good quality roots and were transplanted into peat:perlite (4:1) substrates and acclimatized in a greenhouse under controlled conditions. We developed a complete micropropagation protocol for cvs. ‘Meader’, ‘Elizabeth’ and ‘Liberty’ blueberry. This protocol can be used for the production of certified vegetative material or different biotechnological purposes.

It is important to use light that has a positive effect on plants. For plant growers, achieving the lowest possible cost of shrub production is crucial. We investigated the influence of light (white and violet LEDs as well as fluorescent white and red light) on the rooting and growth of blueberry cuttings (V. corymbosum L.) 'Aurora' and 'Huron'. Blueberry cuttings (4 cm tall) were planted into boxes with peat, which were placed in a phytotron at 22 °C and illuminated for 16 hours a day. The plants died under the red fluorescent light source and, therefore, we discontinued its use. The other three light sources had a positive effect on plant growth and development. The light source had little effect on the content of macroelements in the leaves. Plants grown under white fluorescent and white LED light did not significantly differ in the height (22.0-25.8 cm), proline (4.67-7.23 μmol g-1), and polyphenol content (4987-5212 mg 100 g-1). In both cultivars, the violet LED light reduced plant growth and increased the content of polyphenols (6,448 mg 100 g-1) and proline (8.11-9.06 μmol g-1) in the leaves, which may indicate abiotic stress.  During the rooting of highbush blueberry cuttings, it is advisable to use white LED light. It has a positive economic impact on crop production due to low electricity consumption and it benefits the environment by eliminating mercury. The plant quality is similar to that of fluorescent white light.

The consumption of highbush blueberries has been growing rapidly in recent years due to their taste and health-promoting qualities. Various solutions have been sought to obtain the highest quality fruit after harvest. In the era of eco-friendly products, it is important that the methods used are natural and ecological. For this purpose, chitosan (CH) was sprayed five times on highbush blueberry bushes before harvesting. Different molecular weights of CH (5, 12, 21, 50, 125, and 500 kDa) were used in this study. The physical and biochemical characteristics of the fruit were investigated. The antioxidant activity, microbial contaminants, and mycotoxins in fruit were also analysed. Application of CH affected the quality of highbush blueberries after harvest. The molecular weight of CH had a significant effect on the studied traits. The application of high-molecular-weight CH improved physical characteristics such as the average weight of 100 blueberries, firmness, and puncture. Furthermore, the blueberries had a more intense blue colour; were characterised by a higher content of l-ascorbic acid and polyphenols, especially anthocyanins; and did not contain mycotoxins. Spraying with CH can be recommended in the organic cultivation of highbush blueberries to obtain robust fruit with health-promoting qualities.