Biochar was tested as a possible soil amendment for blueberry production and compared with pine bark, which is commonly used as a soil amendment in blueberry production in the southeastern United States. Three treatments were established in sandy soil: biochar, pine bark (commercial standard), and control (non-amended soil) in which the variety ‘Farthing’ was planted. Soil characteristics were measured two months and 11 months after the incorporation of the amendments. Plant growth, and physiological traits were measured a year after planting. Biochar increased soil pH compared to pine bark and non-amended soil (control). Organic matter (OM) was higher in pine bark amended soil than in biochar. Biochar increased the Ca/Mg ratio 2 months after its incorporation and maintained P availability compared to the control and pine bark treatments. Eleven months after the incorporation of the amendments, the aluminum content was higher in the soil amended with biochar than in the control, whereas the Fe content was higher in the soil amended with pine bark than in the control. Manganese levels were lower in the pine bark-amended soil than in any other treatment. Plant growth and physiological responses were not affected by the incorporation of biochar as a soil amendment. However, plants established on the pine-bark amended soil had lower Soil Plant Analysis Development (SPAD), stomatal conductance, and maximum fluorescence than blueberry plants established on biochar or non-amended soil.
Blueberry cultivation is rapidly expanding due to a dramatic increase in the consumption of the fruit. Soilless substrates have been viewed as a method to increase the production and geographic availability of this fruit. The identification of optimal and alternative substrates for the growth and development of the plants is needed to further guide a new and growing industry. The purpose of this study was to investigate the suitability of aped pine bark substrates amended with coconut coir or wood fiber substrates produced from Pinus taeda for container production of southern highbush blueberry (Vaccinium sp.). Plant linears of ‘Star’ blueberry were grown in 7.3-L pots filled with substrates consisting of coconut coir, aged pine bark, and hammermilled wood fiber. These were each amended at three rates (0%, 20%, 40%, 60%, 80%, and 100%). The plants were harvested at 0 days, 70 days, 140 days, and 365 days to assess their growth and development, measuring plant dry weight at each interval. Additionally, the substrate's physical properties, including particle size and air space, were measured during these four periods to determine the degradation and its influence on substrate quality over time. The findings of this study suggest that coconut coir usage can be reduced by using wood fiber or aged pine bark due to the positive effect on early vegetative blueberry growth.
Fruit quality parameters are typically reported by growers and researchers as an average. However, for small fruits such as blueberries, berry-to-berry variability in texture and flavor also impacts the consumer eating experience. The objective of this project was to capture how the uniformity of fruit quality parameters varies by 1) cultivar, 2) berry maturity, and 3) exogenous phytohormone applications. From 2022-2023, analyses were conducted on individual blueberries from multiple studies carried out in commercial fields in Michigan. First, we compared the uniformity of berry mass, diameter, firmness, and total soluble solids (TSS) in six northern highbush blueberry cultivars: “Duke,’ ‘Bluecrop,’ ‘Draper,’ ‘Calypso,’ ‘Elliott,’ and ‘Aurora.’ The uniformity was highest/lowest for berry mass in 'Bluecrop'/'Calypso', firmness in 'Bluecrop’ /‘Aurora,’ and TSS in 'Bluecrop'/'Elliott'. Second, we evaluated how changes in berry maturity due to delayed harvest affected the uniformity of berry mass, diameter, firmness, TSS, pH, total acidity (TA), TSS/TA, and aroma volatile concentrations in: ‘Duke,’ ‘Draper,’ and ‘Calypso’. Delayed harvest did not alter the uniformity of berry mass or TSS, but increased the uniformity of TA and TSS/TA in all three cultivars. The implications of delayed harvest on the uniformity of consumer liking scores will also be discussed. Finally, we tested whether exogenous application of multiple phytohormones impacted the uniformity of berry mass, diameter, firmness, and TSS in ‘Bluecrop’ and ‘Elliott’. Abscisic acid improved the uniformity of berry mass in 'Elliott,' but not firmness or TSS. Meanwhile, jasmonates had a limited effect on the uniformity of fruit quality parameters in 'Bluecrop'. The relative importance of the "average" and "uniformity" of fruit quality parameters will be discussed. We conclude that “uniformity” is an important component of fruit quality in blueberry.
Blueberries rank among the top ten agricultural commodities in Georgia, contributing 2.45% to the state's GDP, with 27,000 acres across the state and a farm gate value of $449.4 million. Blueberry plants are exposed to elevated temperatures and intense solar radiation during the growing season. This research aimed to reduce adverse environmental effects by modifying the spectral distribution of sunlight. Our team examined the application of photoselective devices Opti-Gro and ChromaGro in blueberry production in Georgia. The research experiment was conducted at two locations (Alma and Rebecca, GA) using a randomized complete block design with four treatments: T1 (Opti-Gro), T2 (ChromaGro), T3 (a commercial grow tube), and T4 (control-unprotected plant), each replicated five times. Photoselective devices positively impacted plant height, yield, total soluble solids, anthocyanins, and titratable acidity. Plants under T1 and T2 also resulted in higher net photosynthesis and stomatal conductance. In summary, the use of photoselective devices presents a promising approach to improve blueberry production in Georgia.
Agronomic crops have their yield potential assessed once per growing season at harvest time. In contrast, horticultural crops such as blueberries (Vaccinium spp.) require prolonged harvest periods, spanning 6 to 8 weeks of recurrent mechanical- or hand-picking. Collected data throughout the harvest period offer a comprehensive source of information to estimate production curves (cumulative harvest). These capture the yield dynamics of each cultivar under specific environmental conditions and treatments. For blueberry growers in Florida, desirable production curves should exhibit: 1) accumulation at the beginning of the harvest season (earliness), and 2) reduced harvest periods (concentration). This pattern is advantageous as it could significantly enhance productivity and profitability while simultaneously cutting down labor costs linked to harvest operations. Thus, pinpointing cultivars displaying these beneficial traits is paramount. In this study, we considered the Weibull distribution to model the production curves for each genotype-in-environment combination. Phenotypic and genomic information were combined for model calibration to predict the corresponding parameters of the distribution besides yield performance in a multi-trait framework. To our knowledge, there are no methods in the current literature that address the identification of cultivars that both ripen early and/or are suited for concentrated harvesting. In this study, we employ a novel analytical approach designed to fill this gap, aiming to systematically identify cultivars aligning with these ideal production characteristics.
