The 'markers' revolutionize the obtaining, registration, nurseries and varietal identification of the citrus sector

A webinar organized by the Gocitrus project concludes that this technology is benefiting all links in the citrus plant breeding industry and that it will soon do so with other crops as well.
They present a pilot test of an APP with all the updated varietal and agronomic information to provide the citrus grower with the best variety-rootstock combination
The first mandarin to use markers as a basis for its varietal certification system was Tang Gold (Tango), from Eurosemillas. Gocitrus will facilitate the expansion of this technology: in 2021 it will obtain the differential DNA sequence of more than 25% of mandarins, 10% of oranges

The term PCR that is in common use today and refers to the most reliable diagnostic method to detect Covid-19 is based on the same technology that is turning the world of the exploitation of citrus plant varieties upside down. Indeed, molecular markers can both serve to define the genetic sequence of a certain coronavirus (or any pathogen) and to provide the specific genetic traits of a variety. “Molecular markers are not the future, they are already the present,” said yesterday Francisco Llatser, the former director for decades of AVASA (Agrupación de Viveristas de Agrios, SA, whose member nurseries account for around 80% of Spanish plant production). His contribution “against varietal piracy is having and will have an incalculable economic impact,” he added immediately. This is how forceful Llatser was during a webinar organized by the Gocitrus project, which also served to demonstrate how this technological revolution is benefiting all links in this chain: it is accelerating varietal improvement processes, technology is beginning to be introduced to reduce the times and tests necessary to obtain registration (the 'patent' of a variety), it has perfected the control of nursery production and is being used in an emerging way in varietal certification and identification systems to avoid fraud.

The meeting, followed online by hundreds of people linked to the citrus sector, was supported twice by the Ministry of Agriculture. On one hand, Alfredo Pollán, head of the Innovation and Digitalization Service, introduced the event and on the other, José Antonio Sobrino, director of the Spanish Plant Varieties Office, gave the first presentation. Sobrino went on to detail how the registration process for a new variety is carried out. In the first instance and beyond other bureaucratic procedures, the new plant material must prove that it is different, homogeneous and stable. Until not too long ago these studies were based exclusively on the analysis of morphological and phenotypic differential characteristics. Faced with them – as Sobrino confirmed – marker technology is also emerging, which allows the process to be accelerated by comparing the candidate variety only with those that are genetically most similar, “rationalizing the reference collections” (which in citrus and in general in all the fruit trees are huge). The UPOV (International Union for the Protection of New Varieties of Plants) – of which the EU is a member as well as most developed countries – has, in fact, a working group (the 'IMODDUS') to incorporate these methods , to generate databases (specific sequences) and protocols for registration processes.

From the legal perspective, as clarified by the lawyer specialized in obtaining law and director of AM Legal Group, Maribel Montero, variety markers are tools increasingly used in courts, both in judicial evidence and as a party, in linked processes. to cases of varietal piracy. “Its implementation for the unequivocal identification of citrus varieties already has a fundamental deterrent value because we no longer depend only on expert reports based on the study of morphological characteristics, which are more complex analyzes and prone to interpretation,” he warned. Along with this and in line with what was previously advanced by Sobrino, Montero was in favor of greater integration of these methods in the registration processes. “The genetic identification of plant varieties, in a globalized market, is already beginning to provide security and progress to the different economic agents in the citrus sector, but it could also do so for all botanical species,” he concluded.

Llatser, on behalf of the nursery sector and as the head of the Ministry of Agriculture also highlighted before, highlighted the “great advance” that the incorporation of this technology has also brought to the controls of the production and marketing of plant reproductive material from nurseries. that carry out the autonomies. “They allow, for example, to avoid the illegal multiplication of protected varieties that can be sold under another name,” he clarified. He also wanted to go into how they have influenced the improvement processes and gave examples: “The development of selection markers by the IVIA to detect sensitivity to the Alternaria fungus has made it possible to rule out hundreds of possible parental varieties for hybridization and has accelerated the mandarin improvement process”.

The first success story of how the use of these unique genetic sequences can also be key in the exploitation of a variety has occurred with the Tang Gold citrus fruit (known as Tango). To testify to this, Gocitrus invited José Pellicer, Development Director of Eurosemillas, which exploits this mandarin and whose firm is one of the project partners. Pellicer detailed the role that patented molecular markers play for Tang Gold in what is perhaps one of the most comprehensive varietal certification systems: Leaf samples are taken from licensed farmers' fields; of fruits in the warehouses of the operators who are registered in the system; Fruits are also purchased in the supermarkets where mandarins are sold throughout Europe, and – in exceptional cases – samples can even be taken at Customs. All of them are sent, respecting the chain of custody by an independent company, to a specialized third-party laboratory that performs the marker tests and in this way, following the traceability of the mandarin, possible violations are controlled (for example, selling labeled like other varieties, Tang Gold mandarins without the breeder's permission).

Immediately afterwards, the director of the Valencian Institute of Agrarian Research (IVIA), Rodolfo Canet, whose center also participates in Gocitrus, intervened. Canet agreed that this technology “is the future although it is also part of the present.” The new director wanted, in this regard, to limit the work of his entity "to working as generators of knowledge" but ruled out - as has been speculated at some point - that the IVIA could become a reference entity "to certify, verify or resolve disputes (about varieties) because these tasks must be developed from the generation of an auxiliary sector.”

Test the APP and generate bookmarks

“Today, choosing the right variety and the most suitable rootstock is a very complicated decision,” Carlos Baixauli, director of the Cajamar Foundation Experience Center, who is also another of the project partners, began by explaining. Immediately afterwards and live, Baixauli showed the simple operation of the first APP that will help citrus growers in such a process. The application contains the information on the IVIA varietal sheets and the harvest calendar that groups them according to whether they are ultra-early, early, mid-season, late and ultra-late. It also integrates a history of quotes, the average climatic data of recent years from the nearest station and allows the interested party to determine if their plot is especially prone to frost. It will launch, where appropriate, alerts to the user if - due to the location of its land - there is a nearby presence of hybrid mandarin varieties that could promote cross-pollination and the presence of seeds in the fruit. And, as important or more than the choice of variety, the application will also assist in choosing the rootstock that best adapts to the climatic conditions of the plot, the characteristics of the land (water salinity, limestone, water stress) or will propose updated alternatives with patterns that are resistant or tolerant to certain viruses or fungal diseases.

This is a second objective of Gocitrus. The first, which is already very close to being fulfilled, is to provide molecular markers for up to 25% of the currently existing commercial varieties of mandarins (more than 300) and for 10% of oranges, among which are all the most commercially demanded ones. .