When the Svalbard Global Seed Vault opens this week, for the first time in 2021, the seeds of something really sweet will be among those deposited.
A package of 500 Fragaria vesca (woodland or wild strawberry) seeds will be deposited by the Institute for Breeding Research on Fruit Crops, part of the Julius Kühn-Institute (JKI) in Germany.
It’s a fitting way to welcome FAO’s International Year of Fruits and Vegetables.
The Institute for Breeding Research on Fruit Crops is the coordination center for the German Fruit Genebank (DGO). It oversees the genebank’s apple, cherry, strawberry, pear, plum, Rubus (bramble fruits) and wild fruit networks.
“Our focus is on maintaining collections of fruits native to Central Europe and species that are important for fruit production in Germany,” says Monika Höfer, the DGO Coordinator and Manager of the institute’s genebank collections, which hold about 4,500 samples of trees or strawberry plants from domesticated fruit and their wild relatives altogether.
Other institutes making deposits in the Seed Vault this month are the Southern African Development Community’s Plant Genetic Resources Centre in Zambia, the Institute of Rural Economy in Mali, AfricaRice in Côte d’Ivoire and the International Crops Research Institute for the Semi-Arid Tropics in India.
On the eve of the Seed Vault opening, Höfer and Henryk Flachowsky, Acting Head of Institute for Breeding Research on Fruit Crops, spoke with the Crop Trust about the work of collecting and conserving fruit genetic diversity from Germany and beyond.
Why are you depositing wild strawberry seeds in the Svalbard Global Seed Vault?
Höfer: We want to use a range of methods to ensure we properly conserve the genes of these valuable fruits. We already have a large collection of more than 300 samples of wild strawberry growing in pots, and we also use cryopreservation [freezing plant tissue in liquid nitrogen] to back up our collection of wild species that are not conserved in the DGO. The Seed Vault gives us an additional backup.
Last year, we deposited seeds of the wild pear species Pyrus pyraster and the wild apple Malus sylvestris. Both samples came from the Eastern Ore Mountains, which span Germany and the Czech Republic.
Step by step, we will continue to add our genebank’s collection in the Seed Vault. So far, we have only a few samples stored there, whereas other genebanks store thousands. The boxes in the Seed Vault are huge but Åsmund Asdal [the NordGen Seed Vault Coordinator] will put this year’s deposit into the same box as last year to ensure that there is plenty of space for future deposits. This is a new routine that aims at a more effective use of the storage capacity of the Seed Vault.
Building our collection is a time-intensive process. It takes a lot of time to produce seeds from enough plants, and then to dry and freeze them and pack them for shipment.
Flachowsky: Yes, that’s important for conserving genetic diversity—if we only have seeds from a few plants, we can’t be sure they represent the full genetic diversity of a species. So, we do genetic analyses to assess how much diversity is in the collection. Once we’re sure a collection is representative, then it’s time to send seeds from that collection to Svalbard—and in doing so, preserve the diversity of the species as a whole.
Is it more difficult to conserve fruits than other plants?
Höfer: Definitely. Most of our fruit species are cross-pollinated and heterozygous. This means that each plant needs pollen from another plant to produce seeds, and the resulting seeds could have a copy of either parent’s gene for a particular trait. So, it’s impossible to conserve the exact same genetic profile of fruit varieties across generations.
For example, each strawberry fruit has 150 to 200 seeds, and each seed has a combination of genes that is different from those of all the other seeds on that strawberry, and the other strawberries on the same plant. So, to preserve the genetic profile of the mother plant only, you have to take a sample of its tissue and store that.
But, if we want to preserve the genetic diversity of a wild species, such as Fragaria vesca, we can still use the seeds because we are interested in storing all of the genetic variation in the species, not just specific varieties.
Where do the plants in your collections come from?
Flachowsky: We carry out collecting expeditions across Germany and other countries to collect samples of wild fruit species.
As a breeding institute, our main interest is in collecting samples that have genes for very specific, useful traits, such as resistances to pests and diseases, tolerances to environmental stresses like drought or heat, or high nutritional content.
However, from a conservation point of view, it’s important to ensure all the genetic variation is preserved. This ensures that if there is a catastrophe, the stored seeds could even be used to restore a region’s natural flora.
By collecting from different regions, we can be sure that the seed is well adapted to different climatic conditions and that it most likely represents greater genetic diversity than if we only collected seeds from one place or region.
Where have you traveled for these plant collecting trips?
Höfer: We went to the Baltic Sea in Germany to collect European wild pear and then had to confirm it was the native species and not a hybrid, before sending the seeds to the Svalbard Global Seed Vault.
Flachowsky: For species in the apple genus, such as Malus sylvestris, which is native to Europe, we collaborated with NGOs in Germany to collect seeds from across the country.
We also went on expeditions to Russia, Georgia and Azerbaijan to collect Malus orientalis, and we collaborated with people who went to Kazakhstan to collect Malus sieversii. Those species are genetically very closely related to our cultivated apple, its closest wild relatives.
In the past, we conducted expeditions to China, which has a huge diversity of apple species. We grew those seeds into seedlings in our collection, and they are now available for crossing with other apple species.
We have also collected wild and cultivated cherry in Turkey, Iran and Azerbaijan.
This is the International Year of Fruit and Vegetables. What is your institute doing to celebrate?
Höfer: We will hold several events over the year.
In June, we have an event on cherry breeding and diversity, and one on berries. This is for fruit growers and nursery owners as well as home gardeners and really anyone else who is interested.
Another event is the Long Night of Science, which is held in early July and is where we present our research projects to the broader community.
And each autumn, we have Apple Day, with a big exhibition of apple varieties. Visitors can taste different varieties and learn about apple diversity, conservation, breeding and so on.
Throughout the year, we also hold dedicated exhibitions for special interest groups. They can visit the JKI as well as the orchard and the genebank. Your readers are most welcome!