Researchers, scientists, technicians and professionals working in the pomegranate field met up in Elche (Spain) for the IV International Symposium on Pomegranates and Minor Mediterranean Fruits on 18th-22nd September 2017. The event was organised by the International Society for Horticultural Science (ISHS), the Elche Agricultural Experiment Station and the Valencian Institute of Agrarian Research (CAMACCDR) in collaboration with the city of Elche and Elche's DOP Mollar.
The Symposium confirmed that the popularity of the pomegranate is growing on an international level. Global production is increasing by over three million tons, 90% of which comes from Iran, India and China. Some regions in the Mediterranean basin, central and southern Italy, Greece, Croatia, Australia, Chile, Peru and South Africa are also interested in their production. Spain is the main European producer and exporter with 4,000 hectares and 60,000 tons. Demand is increasing also because the fruit is now used to make juice and because parts of the fruit and plant are becoming known for their beneficial properties, as well as the fact that new varieties (such as Wonderful, Acco, Parfianka,..) now coexist with traditional ones ("Mollar de Elche").
Click here for an overview of pomegranate varieties.
Over the past few years, in addition to the increase in cultivated areas and the fact that new countries have become producers, research has also expanded, as shown by the number of representatives who took part in the Symposium from over twenty countries including India, China, US, Israel, Italy, Greece, Croatia, Portugal, Albania, Russia, Algeria, Morocco, Pakistan, Turkey, Iran, Australia, South Africa, Peru, Cyprus and Spain. While research used to focus only on the effects of pomegranate compounds on health, increased consumption has led to new research projects on genetic improvement, cultivation techniques related to different environmental conditions, sustainable agricultural production, parasite and disease control, quality and storage improvement and the development of new products.
The plenary session focused on genetic improvement. Dr. Doron Holland (Newe Yaar Research Center ARO, Israel) examined research in relation to biotechnologies and talked about a few aspects of the programme for the attainment of new varieties. Molecular markers are used to assess genetic diversity as well as for the development of markers associated with fruit characteristics useful for genetic improvement applications.
Professor Zhaohe Yuan (Nanjing Forestry University, China) presented the main pomological, agronomical and organoleptic aspects of varieties cultivated in China (over 289 types). He then illustrated the results of agronomic tests, assessments of new local varieties and listed the varieties currently being introduced in India (the key for new hybrids is tolerance to Xanthomonas axonopodis pv punicae), Australia (in four states with different climates ), Italy (Ferdinando Cossio: comparison study on 47 international varieties), Croatia, Algeria, Turkey and other Mediterranean regions.
The session on physiology, biology and development focused on the physical and chemical changes (pH, SST, acidity, colour, phenolic compounds, anthocyanins, etc.) occurring during the various ripening stages and that can help determine the perfect harvesting moment. New ways to improve tree productivity and fruit quality were also experimented through field foliage treatments with compounds acting as growth regulators and oxalic acid, methyl jasmonate or melatonin.
The session on irrigation and fertilisation opened by Dr. Diego S. Intrigliolo focused on the effects of nutritional supplements (singularly or through interactions) on productivity, physical and chemical parameters, organoleptic qualities, shelf-life and functional compounds. In addition, some research studies were presented on how to modulate irrigation restrictions (the blossoming period was identified as the best to favour setting), the use of fertilisers in irrigation, using sets for leaf analysis according to fertilisation, variety, time frame and number of samples needed, as well as the relation between nutritional levels of different parts of plants. The event ended with the presentation of studies aimed at reducing fruit cracking - correct irrigation (especially during the last period of fruit development) and a suitable proportion between N/K, K (Ca + Mg) nutrients within cortex minerals are essential. Boron Zinc applications are also needed for some varieties and conditions.
The pre and post-harvesting fungal disease situation was addressed by Dr. Luís Palou (IVIA, Spain). Other reports focused on Alternaria alternata, which can affect 10-15% of fruits depending on varietal sensitivity and occurs mainly on red varieties. Tests showed that, while some fungicides have a good effect on the pathogen while in the lab, field application needs to be studied more to improve localisation in flowers. The use of chlorogenic acid as a post-harvest treatment was introduced as a new tool to improve shelf-life.
Dr. Selma (CEBAS /CSIC, Murcia) talked about the beneficial properties of pomegranates. Ellagitannins, punicalagin and punicalin are the most important polyphenols showing high anti-oxidant activities. Studies showed that the effects of pomegranate compounds are connected to the type of micro-organisms in the human intestine. Although the symposium focused mainly on pomegranates, other minor fruits were discussed such as jujubes (Ziziphus jujube Mill.), pistachios (Pistacea vera L.), quince (Cydonia oblonga Mill.), myrtle (Myrtus communis L.) capers (Capparis spinosa L.) and prickly pears (Opuntia ficus-indica Mill.).
Participants also visited a company that grows the "Mollar" and "Valenciana" varieties with 20-30 year old trees as well as the Cambayas cooperative, the leading Spanish pomegranate exporter. After a short break at the Hondo Natural Park, the group visited a young pomegranate orchard cultivated with various supporting systems. The tour ended with a visit to the juice factory and the Vitalgrana museum in Catral.
The symposium was followed by a technical seminar which 300 researchers, technicians and growers took part in. The first speech focused on pomegranate cultivation in California (Dr. Erik Wilkins, US) and the second was on "Identification and strategies for control of Alternaria" (Dr. David Ezra, Israel). Then, Ashen Özgüven (Turkey) explained "fruit-cracking causes and solutions."
Last but not least, symposium organiser Dr. Julián Bartual (EEA Elche) illustrated a few aspects to consider when determining the perfect harvesting time. The seminar was followed by a round table with Ángel del Pino (ANECOOP), Ángel Carbonell (UMH), Francisco Oliva (DOP Mollar de Elche), Dan Rymon (Israel) and Robert Salazar (Peru).
In the poster presentation room, participants could taste juices and dishes prepared with pomegranates. Finally, I.S.H.S. members voted Australia as the location for the next international symposium in 2021.
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By Julian Bartual (Agricultural Experiment Station, Elche, Spain) and Ferdinando Cossio (Fruit consultant, Rome).