Firmino Nunes de Lima

Global blueberry production has been increasing annually. The cultivation area in Brazil has expanded with the introduction of new low-chill cultivars, particularly those from the Southern Highbush group. Assessing the nutritional status of plants from different cultivars is essential for successful cultivation. In this context, the objective of this study was to evaluate the nutritional status of Southern Highbush blueberry cultivars (Biloxi and Emerald) under tropical climate conditions of Brasília, Distrito Federal, Brazil. The experiment was conducted in 2023 and 2024 at the Fruit Production Sector of the Biology Experimental Station (EEB) of the University of Brasília (UnB). The region's climate is classified as Aw, tropical savanna, with dry winters and rainy summers, according to the Koppen-Geiger classification. The experiment was conducted in a randomized block design, with 10 replications and 10 plants per experimental unit, totaling 200 plants. The treatments evaluated consisted of two cultivars: Emerald and Biloxi. Leaves were analyzed for nutrient contents: macronutrients included nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S), expressed in grams per kilogram (g kg-1); and micronutrient contents included boron (B), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn), expressed in milligrams per kilogram (mg kg-1). The cultivars had a significant (p < 0.01) effect on leaf macronutrient (N, P, K, Ca, Mg, and S) and micronutrient (Fe, Mn, Cu, Zn, and B) contents in both years evaluated. The cultivar Emerald exhibited higher accumulation of N, P, Zn, and Cu, whereas the cultivar Biloxi showed greater accumulation of K, Ca, Mg, S, Fe, Mn, and B in leaf tissues.

Consumer interest in natural antioxidants has risen because their intake is linked to the prevention of chronic diseases. Blueberries (Vaccinium spp.)—rich in flavonoids, vitamin C and other bioactive compounds—are therefore being cultivated beyond temperate regions. In tropical areas, however, the lack of chilling hours may alter fruit physiology, and little is known about how pruning practices modulate quality under these conditions. The objective of this study was to quantify the effects of pruning types and seasons on the antioxidant activity, physical and chemical characteristics (TSS, TTA, TSS/TTA), and ash, moisture, and fiber contents in blueberries of the cultivar Biloxi grown under tropical climate conditions (without chilling hours), in Brasilia, DF, Brazil. The trial followed a randomized-block design with three replications. Plants received either severe pruning removing lateral branches (SPRLB) or severe pruning maintaining lateral branches (SPMLB) in winter, spring, summer or autumn; fruit harvested over the subsequent four weeks was analysed for DPPH radical-scavenging capacity, total soluble solids (TSS), titratable acidity (TTA), TSS/TTA ratio, ash, moisture and fibre contents. Pruning season exerted the strongest effect. Autumn pruning—regardless of type—produced the highest antioxidant activity and elevated TSS. SPRLB increased TTA, whereas SPMLB enhanced the TSS/TTA ratio during warmer seasons. These findings demonstrate that pruning season plays a key role in enhancing blueberry fruit quality under tropical conditions.

Global blueberry production more than quadrupled between 2010 and 2022. One of the factors contributing to this production growth was the development of new cultivars with little or no chilling requirements, capable of thriving in tropical regions. Therefore, the objective of this study was to assess the growth and fruit yield of blueberry plants (Biloxi cultivar) subjected to different pruning types and timings in the Distrito Federal (DF), Central-West region of Brazil. The experiment was conducted in an open field, using a randomized complete block design with 3 replications and 10 plants per plot, totaling 480 plants. The plants were grown in pots using a fertigation system and were subjected to two types of pruning (severe pruning and regular pruning) in the different seasons of the year. The plants were evaluated for vegetative growth, fruit yield, number of fruits per plant, mean fruit weight, and fruit transverse and longitudinal diameters. The results showed that Biloxi blueberry can be grown under the climate conditions of the central region of Brazil, during the four seasons of the year, despite the tropical climate conditions and no occurrence of temperatures lower than 7.2 °C. Higher fruit yields were found when pruning was performed in winter or spring. Severe pruning resulted in higher fruit yields compared to regular pruning in winter. Summer and autumn pruning treatments reduced fruit yield; however, it is an alternative to extend the production window of this crop in Brazil.

Blueberry production is increasing in Brazil, and growers are turning to bio-inputs or biostimulants to be used on their growth. This has been due to the growing concern about sustainability in the food production chain and the necessity to increase the yield. The current experiment aimed at evaluating the effects of Samurai King, EM-1 and Brutal Plus (Minhofértil) biostimulants on the cultivation of Southern Highbush blueberries (V. corymbosum L.), cultivar 'Biloxi'. The parameters evaluated were plant height (cm), diameter of the main stem (mm), number of shoots, chlorophyll content, total number of leaves, leaf length and width. The total mass, number of fruits, average mass per fruit, the transversal and longitudinal diameters, and the total sugars (°Brix) were also measured. In 2020, the treatment of Samurai King + EM-1 showed the highest efficiency for the studied parameters related to fruits and yield but with no significant difference as compared to the other treatments. Regarding the plant growth, treatments 1 (Brutal Plus) and 5 (Brutal Plus + EM-1) were the most efficient. In 2021, treatment 7 (Brutal Plus + Samurai King + EM-1) had the highest yields, except for average mass per fruit and total sugars. In the two years of evaluation, although treatments obtained lower averages than the control, the effect observed was generally positive, revealing the efficiency of products containing microorganisms for the growth of blueberry plants. In conclusion, these bioproducts could remarkably affect plant biomass, production and fruit quality, resulting in better yields.

In Brazil, the nutritional requirements of the blueberry are not sufficiently known, thus requiring further research on the management of mineral fertilization. In this perspective, this work aimed to evaluate physiological attributes of Southern Highbush blueberry plants cv. Biloxi as a function of nitrogen fertigation in Brasília-DF. The experiment was conducted from August 2018 to July 2019, in the Fruit Sector of the Experimental Biology Station of the University of Brasilia (UnB), Federal District. This experiment adopted a randomized block design, with four treatments: 10; 20; 30, and 40 g of N plant-1, 8 replications, and 5 plants per experimental plot. The following variables were measured: net photosynthesis rate (A), transpiration (E), stomatal conductance (gs), internal CO2 concentration (Ci), instantaneous water-use efficiency (WUE), carboxylation efficiency (CE), SPAD index (SPAD) and leaf nitrogen (N). There was an effect of the different nitrogen doses applied on the physiological attributes. The plants of the blueberry cultivar Biloxi increased their photosynthetic rates at doses up to 30 g of N plant-1. Nitrogen rates did not influence stomatal conductance nor did they provide improvements in the carboxylation efficiency of the blueberry plants. Under the conditions of the present work, the highest N leaf contents were obtained with the application of 30 g N plant-1, and values above this concentration did not correspond to higher net photosynthesis rates, transpiration, and CO2 concentration in the leaf mesophyll.