Olive Variety Identification Moves From Pits to DNA
Olive variety identification no longer needs an expert squinting at olive pits: the University of Córdoba and its spin-off IDolive now identify olive trees from their DNA, checked against a reference collection of about 500 varieties. The service is aimed at nurseries and growers who need to know exactly what they are planting. Here is how it works, what it costs, and why a wrong label on a young tree is such an expensive mistake.
What was reported
Olive Oil Times reported this week that the University of Córdoba, long a center for olive variety research, has moved its identification work on to molecular markers. Until now, identifying an unknown olive usually meant comparing its pit with a large collection of pits, a slow job that depended on one resident expert. That collection is still kept and still growing, but samples are now identified with microsatellites, short stretches of repeated DNA that vary a great deal between varieties, read using PCR, the same amplification method used in medical labs.
The profile from an unknown sample is compared with the database of the university’s pomology group in the Department of Agronomy, which holds about 500 varieties from 22 countries. The commercial side is handled by IDolive, a spin-off founded in February 2011. When it launched, its co-founder Estrella Rodríguez told Spain’s science news agency SINC that the whole process runs online: the customer fills in a form, posts a leaf sample, and gets results on the web within 20 days. Olive Oil Times put the price at about $140 a sample.
| The service at a glance | Detail |
|---|---|
| Who runs it | University of Córdoba and its spin-off IDolive |
| Method | DNA microsatellites read by PCR, compared with a reference database |
| Reference collection | About 500 varieties from 22 countries |
| Sample | A leaf, sent by post after an online form |
| Turnaround and cost | About 20 days; about $140 a sample |
| Also offered | DNA screening of young plants for fungi, bacteria and viruses |
Why it matters
A wrongly labeled olive tree is a slow disaster. The mistake only shows up years later, when the tree starts to crop and the fruit, the oil or the ripening date is not what the grower planned for. By then the grove is planted and the money spent. Checking the variety before propagation is cheap insurance, which is why the company’s main customers, according to SINC, are nurseries, farmers and research centers. The same DNA method is used to check plants for pathogens, which Spanish rules require before nursery stock can be certified.
The service also answers an old question. As the California consultant Alexandra Kicenik Devarenne told Olive Oil Times, growers keep finding century-old trees that make great oil and nobody can say what variety they are. A DNA profile can settle it, and says something about where the trees came from.
What comes next
- Table olives. IDolive has been working with Interaceituna, the Spanish table olive body, on identifying varieties in cured olives, where labeling errors are common. It is harder, because curing damages the DNA.
- Other crops. The founders have said they may apply the same approach to other plants.
The variety on a garden center olive tree is only as reliable as the nursery that propagated it, and mix-ups in propagation are more common than anyone selling trees likes to admit. If you are planting more than a couple of trees for oil, buy certified stock from a specialist nursery and ask how the mother plants were verified. It costs a little more than a cheap tree and saves years.
For the varieties themselves, see Olive Varieties of Spain: A Field Guide and Olive Varieties of Italy: A Field Guide. Old trees and the questions they raise turn up in From the Archive: Crete Counts Its Ancient Olive Trees (2009).
Sources
- Olive Oil Times: Olive Identification Gets Fast and Easy
- SINC: Crean un servicio pionero para identificar variedades de olivo (in Spanish)