Seed Longevity and Survival of Seed Borne Diseases after 30 Year’s Conservation in Permafrost. REPORT FROM THE 100 YEAR STORAGE EXPERIMENT
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OriginalversjonNordGen Publication Series: 2019:04 https://www.nordgen.org/en/publications/seed-longevity-and-survival-of-seed-borne-diseases-after-30-years-conservation-in-permafrost/
The Nordic Gene bank established the 100 year seed storage experiment in Coal mine no. 3 outside Longyearbyen in 1986. Security duplicate samples of the Nordic seed collection had been deposited in permafrost in the coal mine since 1984. The experiment was established with the aim to monitor the longevity of seeds in this Nordic back-up seed collection and to gain general knowledge about the longevity of seed stored under permafrost conditions, as well as studying the survival of seed borne plant pathogens. The experimental set up included in total 41 seed lots of 17 agricultural and horticultural crop species commonly grown in the Nordic countries. The seed germination experiment included two or three varieties of each crop. The experimental part dedicated to studies of pathogen survival included seeds from 11 crops naturally contaminated by pathogens. The test program comprises germination and pathogen survival tests every 2.5 years during the first 20 years and then every 5 years for the last 80 years. In total 25 identical sets of test seeds placed in sealed glass tubes were packed in wooden boxes, one box for each planned test year. The tests have been carried out according to schedule and this report sums up the results from the first 30 years of the experiment. All tests have been carried out in accordance with the same ISTA-protocols. The results show that 9 of the 17 species after 30 years had retained more than 90 percent of their initial germination percentage. Beet (Beta vulgaris),Onions (Allium cepa), Cucumber (Cucumis sativus) and Kentucky bluegrass (Poa pratensis) had retained between 97 and 99 percent. At the lower end of the scale, rye (Secale cereale) had lost 51 percent of the initial germination percentage. Among the other cereals, barley (Hordeum vulgare)showed the highest viability as it had kept 89 percent viability, whilst wheat (Triticum aestivum) had kept 79 percent of the initial germination percentage. Mean germination of all test samples showed a drop from 87.2% at year0 to 76.9% at year 30. The pathogen tests showed that all pathogens had survived over the 30 years, more or less at the same contamination levels as were detected at the start of the project. To expand the knowledge about seed longevity under long-term seed storage it is recommended to establish a new more comprehensive experiment with seed materials from a wider selection of crops, and to include more replicates and seeds produced over more years, allowing more indepth statistical studies of the longevity development. A new experiment should be placed in the Svalbard Global Seed Vault, in order to provide results relevant for optimal gene bank conservation methods at -18°C and giving direct data on the longevity of seeds stored in the Seed Vault.