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To better understand the effect of growing location on the phytochemical compounds and sensory properties of blueberry (Vaccinium spp.), here we investigated rabbiteye blueberry 'Brightwell' (Vaccinium ashei cv. 'Brightwell') grown in 10 locations of China. Significant differences in terms of total soluble solids, titratable acidity, flavonoids, phenols, as well as proanthocyanidins and anthocyanins, were found in the fruits (berries) of blueberry plants among the different sampled locations. Furthermore, their sensory properties, which evaluated by the electronic tongue method, also significantly differed among the 10 locations. The content of flavonoids, phenols, proanthocyanidins, and anthocyanins all had significant correlations with sensory properties, except that of aftertaste-astringency. A key finding to emerge was that blueberry plants grown at high altitude locations harbored a high content of total soluble solids, flavonoids, phenols, proanthocyanidins, and anthocyanins along with high scores for the sweetness. These results suggested cultivating blueberry at high altitude can produce fruit that not only possess pronounced beneficial health effects but also good taste. [ABSTRACT FROM AUTHOR]

Calcareous soils are not suitable for blueberry cultivation. Our aim was to improve the performance of blueberry plants in calcareous soils by using pits filled with growth media in combination with high levels of RNH4+ (proportion of N-NH4+ among the total applied N). Rabbiteye blueberry (Vaccinium virgatum Ait. cv. Ochlockonee) plants were grown in pits filled with a tuff/peat mixture (TP), a sandy soil (S) or a calcareous (CC), in full factorial combination with three levels of RNH4+: 33%, 66% or 100%. The two higher RNH4+ treatments decreased the pH of the low-CaCO3 (S) and no-CaCO3 (TP) media to ≤6.0 over 250 days of fertilization, but did not affect the pH of the CC soil over 650 days. Plant performance was superior in the TP and S media, as compared to the CC soil. The type of growth medium was the dominant factor accounting for the improved plant performance. The plants were sensitive to Mn deficiency in leaves during the spring period. The current results suggest that growing blueberry in pits filled with good aeration and low pH buffering capacity medium in combination with a high level of RNH4+ is a positive approach for its cultivation in calcareous soils. [ABSTRACT FROM AUTHOR]

• Increased RNH 4 + reduced the pH of the leachate and growth medium to below 5.5. • Reduced pH was associated with elevated Fe, Mn and Zn levels in the leachate. • Reduced pH increased chlorophyll concentrations, water uptake and foliage volumes. • Leaf Mn concentrations increased significantly following the drop in pH. The increased demand for blueberries and limited availability of low-pH soils have led to the increased use of soilless culture systems. The objective of this study was to evaluate the effect of a wide range of RNH 4 + [RNH 4 + = 100*N-NH 4 +/(N-NH 4 ++N-NO 3 −)] values on the acidification of the growth medium and the nutrient status and performance of blueberry plants. RNH 4 + treatments of 25% (AN25, control), 50% (AN50) and 100% (AN100) and a 25% N-NH 4 + plus concentrated sulfuric acid (AN25-acid) treatment were applied by fertigation to southern highbush blueberry plants (Vaccinium corymbosum , cv. Sunshine Blue) grown in a soilless substrate (50% tuff, 25% peat, 25% coconut coir). The original solution for the AN25-acid treatment was adjusted to a constant pH of 4.5. The pH and mineral concentrations in the leachate, pH of the growth medium and mineral and chlorophyll concentrations in the leaves were monitored periodically. Plant water uptake was monitored periodically and foliage volumes were calculated at the end of the growing season. Application of high levels of RNH 4 + decreased the pH of the leachate and medium to below 5.5 and increased the concentrations of Fe, Mn and Zn in the leachate, as compared to the control treatment. Those treatments also increased the chlorophyll concentrations, total plant water uptake, foliage volumes and leaf Mn concentrations relative to the control treatment. The effects of the high-RNH 4 + treatment on acidification and plant performance were not significantly different from the effects of the commonly used AN25-acid treatment. It seems, therefore, that the increased RNH 4 reduced the pH of the growth medium to the required level for blueberry production, providing a safer and more environmentally friendly alternative to the use of sulfuric acid. [ABSTRACT FROM AUTHOR]