02 May 2023

The Blueberry School opens the programme of International Blueberry Days


The International Blueberry Days program opened today in Ancona with the Blueberry School. The Marche Polytechnic University hosted a technical day reserved for researchers, agronomists and scholars, with a focus on key technical and scientific advances on various aspects of the blueberry supply chain.

After a welcome from Davide Neri, director of the Department of Agricultural Sciences, the proceedings were opened by Bruno Mezzetti, who introduced a dense program of international speakers intended for an equally global audience.

Blueberry School speakers.

The first report was presented by Susan McCallum of the James Hutton Institute, who outlined the main challenges that blueberry is facing revolve around climate change, the increased incidence of imported product, labor shortages, and marketing windows that are being reshaped and in some cases narrowed. A study conducted in major European supermarkets was also presented that showed that the consumer satisfaction index is highly variable across stores (even for the same variety and over the same period) and generally low, with only 44 percent of consumers giving a positive assessment.


Maurizio Rocchetti of Costa Group presented the results of an in-depth study to optimize pollination of blueberry in the group's Australian productions.


Ebru Kafkas presented the strong development trend that has seen the cultivation of blueberry in Turkey in recent years, which is now widespread both in soil (the Bursa area has soils with an acidity of 4.55.5) and above ground (in the provinces of Antalya and Rize). The geographical distribution of blueberry production changes every year, with new and expanding areas taking the place of other areas in the ranking. A total of about 4,000 hectares are in production in the different regions of Turkey.


Pedro Bras de Oliveira described the production of blueberry in Portugal and some studies regarding the extension of the production season. The results of different types of cover (polyethylene, white net, silver net) and frigoconservation of plants over the length of the season were presented. All these methods must balance the gains in season lengthening with the losses in productivity. Each method must be tested individually for each variety, as results can vary greatly for different cultivars.


Stefano Predieri (CNR - IBE) elaborated on the sensory and hedonic properties of blueberry and the methodologies to analyze and describe them. Hedonic satisfaction is studied by consumer science and deals with consumer acceptability and quality aspects described with more or less positive liking. Panels, on the other hand, deal with sensory properties through experts, detailed descriptions, sensory profiles and the description of key attributes. Finally, intrinsic properties are analyzed by laboratory analysis using various instruments that measure different parameters (color, brix, acidity). This is a complex topic that aims to analytically determine the perception of the product in order to give the entire supply chain the necessary information to meet the needs of the consumer.


This research is also essential for identifying different target consumers: for example, women in general and certain segments of middle-aged men who want to improve their health status through physical activity and healthier eating are more sensitive to health issues.

Cheng Liu (Liaoning Institute of Pomology) presented a broad and in-depth overview of the blueberry crop in China, which has more than 60,000 hectares. Thanks in part to greenhouse production, China's production season spans 12 months in currently 28 provinces out of 34 total, which is almost the entire country. Citing data from IBO, Liu showed the production trend, which has reached 69000 hectares and 477,000 tons. Greenhouse area is 2010 hectares with production of 15185 tons (2021). High tunnel production covers 705 hectares with a total production of 7510 tons.


As of 2018, Southern Highbush varieties are also being introduced for greenhouse production, whereas previously production was focused on Northern Highbush varieties. These new types are enabling better results for producers who, with earlier product, are able to access more profitable market periods.

Liu then showed the different models of greenhouses used in China, with cables, oval-roofed, U-shaped, with brick walls, earth, fabric, and stone. A very modern type of large greenhouse (150m x 5m with a height of 6m) was also presented. 

Ten-year-old varieties were mainly of the Northern Highbush type (Bluebrop, Duke, Berkeley) while now they are planting mainly Misty, O'Neal, Jewle, Emerald, Legacy, that is, varieties of the Northern Highbush type.

The research team led by Cheng Liu includes fifteen people and specializes in the production of blueberry in greenhouses: results include a research program regarding blueberries SHB in greenhouses, the development of greenhouses in the northern parts of the country, and a new method of pruning at the end of harvest for the SHB type both in greenhouses and in the open field.

Portuguese agronomist and consultant Jorge Duarte explored pruning as a function of increasing productivity and adapting to next-generation cultivars. Pruning has several purposes: to control plant vigor, to optimize productivity by controlling older wood where yield drops, to improve the efficiency of harvesting operations, and to better manage the risk of disease and insect damage. Duarte explained in detail what needs to be removed during pruning and what plants look like before and after pruning. Examples of different pruning techniques were also given, also adapted to different varieties that have different structures and needs. Plant sanitation, a very important aspect to reduce contamination risks during pruning, was also addressed.


After Jim Olmstead, global breeding director blueberry at Driscoll's it was the turn of Lara Giongo. The researcher from Fondazione E. Mach focused her talk on texture and postharvest. FEM's blueberry breeding program is based on a germplasm collection, several production sites, propagation laboratories, pomological, texture and storage analyses, a volatile compound profiling platform and a sequencing and genotyping platform.

The breeding program considers 20000 different seedlings per year on which a long selection process is activated. Traits are analyzed according to the quality measurable by the five senses: sight, touch, hearing, smell. Quality is analyzed by phenotype and genotype analysis. FEM is part of VacCAP, an international network of collaboration in applied research.

How to measure quality objectively and instrumentally? In 2022, FEM published a study for texture analysis using several techniques: a flat probe, a pointed probe, and a final dual compression probe. FEM identified 34 parameters for texture profiling. 


FEM in recent years has also worked on the "sound" produced by blueberries, measuring its intensity on a scale on which other crisp foods are normally rated. Each variety has developed a different sound profile and intensity.

A third component of quality is aromatic compounds. Again, each cultivar has its own specifications and behavior at various stages of ripening and postharvest. Ethylene production was found to be highly genotype-dependent and present in only a few genotypes.

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