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Highbush blueberries (Vaccinium spp.) are cultivated crop plants worldwide and they are still gaining importance. However, a common uniform description of the phenological development was missing so far. In this work, a specific code is presented, based on the decimal BBCH scale. The BBCH scale comprises the macrostages 0–9, with macrostage 4 being omitted here, because it has no relevance for blueberry crops grown in the field. Each macrostage is subdivided in several microstages, each describing a notable developmental stage. The BBCH code takes special reference to the fruit development, fruit ripening, and several fruit pickings, which are typical for blueberries. For each macrostage the main development as well as cultivation characteristics are explained in more detail. The new BBCH code is compared with other descriptions of phenotypical development of highbush blueberries and transformations are suggested. The BBCH code is developed for cultivated highbush blueberries and is therefore applicable to northern, southern, and rabbiteye blueberries as well. [ABSTRACT FROM AUTHOR]

Elicitors of plant defence responses can trigger defence mechanisms that are able to protect plant tissues from biotic or abiotic stresses. Since one defence response involves the activation of secondary metabolites' biosynthesis, the purpose of this study was to evaluate the effect of chitosan and melatonin pre-harvest treatments on the quality and the nutritional parameters of the fruits of blueberry (Vaccinium corymbosum L.). Across the two years of experiment, three different cultivars (cv.s. 'Cosmopolitan', 'Hortblue Poppins' and 'Legacy') were treated with 1% chitosan or 100 µM melatonin every two weeks during the ripening season and ripe fruits were progressively harvested and analysed. The treatment with both elicitors had only slight effects on dry matter, soluble solids content, titratable acidity and pH, with a cultivar-dependent response. On the other hand, elicitors significantly affected the levels of phenylpropanoid and antioxidant compounds in all cvs. in both years, with a higher accumulation of total anthocyanins and phenolics and the enhancement of the antioxidant capacity, with positive effects on the nutraceutical quality of fruits. The anthocyanin profile in terms of both absolute concentrations and the relative proportion of single anthocyanins was affected by both harvest year and cv., highlighting the role of the genetic background in the plant response to environmental conditions (with particular reference to summer heat stress) and to elicitor treatments. [ABSTRACT FROM AUTHOR]

Elicitors of plant defence responses can trigger defence mechanisms that are able to protect plant tissues from biotic or abiotic stresses. Since one defence response involves the activation of secondary metabolites’ biosynthesis, the purpose of this study was to evaluate the effect of chitosan and melatonin pre-harvest treatments on the quality and the nutritional parameters of the fruits of blueberry (Vaccinium corymbosum L.). Across the two years of experiment, three different cultivars (cv.s. ‘Cosmopolitan’, ‘Hortblue Poppins’ and ‘Legacy’) were treated with 1% chitosan or 100 µM melatonin every two weeks during the ripening season and ripe fruits were progressively harvested and analysed. The treatment with both elicitors had only slight effects on dry matter, soluble solids content, titratable acidity and pH, with a cultivar-dependent response. On the other hand, elicitors significantly affected the levels of phenylpropanoid and antioxidant compounds in all cvs. in both years, with a higher accumulation of total anthocyanins and phenolics and the enhancement of the antioxidant capacity, with positive effects on the nutraceutical quality of fruits. The anthocyanin profile in terms of both absolute concentrations and the relative proportion of single anthocyanins was affected by both harvest year and cv., highlighting the role of the genetic background in the plant response to environmental conditions (with particular reference to summer heat stress) and to elicitor treatments.

Blueberry is a crop grown worldwide due to the excellent quality and high polyphenol content of its fruit and tolerance to cold conditions. We investigated the influence of three production systems, namely an open field, heated greenhouse, and non‐heated (plastic) greenhouse, on the phenolic characteristics (total phenolic, flavonoid, and anthocyanin content) and antioxidant capacities of "Spartan" (northern highbush), "Sharpblue" (southern highbush), and "O'Neal" (southern highbush) blueberry cultivars. The non‐heated production system showed the highest phenolic characteristics and antioxidant capacity in "Spartan" and "O'Neal," while the open field production system showed the highest phenolic characteristics and antioxidant capacity in "Sharpblue." Derivatives of delphinidin and malvidin were two of the most abundant anthocyanins. The heated greenhouse production system resulted in larger amounts of delphinidin derivatives compared with the other production systems, while the blueberry grown in the non‐heated greenhouse produced larger amount of malvidin derivatives. The anthocyanin profiles varied according to production system and blueberry cultivars. The principal component analysis loading plot of blueberries for individual anthocyanins explained over 95% of the total variance. In summary, the results of this study suggest that a strategic approach to blueberry production could elevate the phenolic content and antioxidant capacity of cultivated blueberry. Practical Application: The highbush blueberry, a rich source of bioactive polyphenols, is a popular fruit. The microclimate of the production system of highbush blueberries affects the concentrations of antioxidative phenolic compounds such as anthocyanins. Therefore, discovering and applying the appropriate method of production for each blueberry cultivar could facilitate production of high‐quality blueberries rich in phenolic antioxidants. [ABSTRACT FROM AUTHOR]

The volatile compositions of eight blueberry cultivars ('Premier', 'Gardenblue', 'Legacy', 'Brigitta', 'Misty', 'O'Neal', 'Bluerain' and 'Northland') grown in the middle region of China were investigated. Volatiles were extracted by headspace solid‐phase microextraction (HS‐SPME) and analysed by gas chromatography—quadrupole time of flight—mass spectrometry (SPME‐GC‐QTOF‐MS). A total of 28 volatiles were identified and quantified, including 5 esters, 11 terpenoids, 3 aldehydes, 6 alcohols and 3 volatile phenols. Different blueberry cultivars had distinct varietal volatile profiles. Rabbiteye cultivars, 'Premier' and 'Gardenblue', were characterized by a large amount of esters, especially for ethyl acetate. 'Misty' had the highest terpenoid content. Principal component analysis (PCA) and partial least squares regression (PLS) were selected to correlate the chemical data with sensory perceptions. PCA showed that esters were dominant in rabbiteye blueberries, especially for ethyl acetate. No distinct pattern of volatile profile was found for the highbush and half‐highbush blueberry cultivars. PLS showed that the grassy descriptor was positively correlated with linalool and hexanal. The minty descriptor was positively correlated with eucalyptol. [ABSTRACT FROM AUTHOR]

Variability in soluble solids (SS), titratable acidity (TA), SS/TA, pH, total phenolic content (TPC), ferric reducing ability of plasma (FRAP), total monomeric anthocyanin content (TMAC) and levels of vitamin C were evaluated in a broad array of northern and southern highbush ( Vaccinium corymbosum ) and rabbiteye ( Vaccinium virgatum ) cultivars of blueberry, grown in different locations and years. When cultivars were grouped by decade of release, there were few significant overall trends observed over years in fruit quality and phytochemical content; however, individual cultivars varied significantly for all the traits analysed. Considerable overlap in most quality and phytochemical characteristics were found among cultivars of the three blueberry types, suggesting that genetic barriers do not exist among the various types of blueberries with regard to breeding cultivars with comparable sugar, acid and phytochemical properties. There were significant negative correlations observed between fruit weight and SS, TPC, FRAP and TMAC, suggesting that as breeders have been selecting for larger fruit, they have inadvertantly selected for tarter fruit with lower antioxidant capacity. However, SS was correlated positively with FRAP and TMAC, indicating that cultivars can be developed that have high antioxidant capacity and anthocyanin content, combined with high sugar content. [ABSTRACT FROM AUTHOR]