Gatersleben Genebank Research Articles

Changes of soluble sugars and ATP content during DMSO droplet freezing and PVS3 droplet vitrification of potato shoot tips

The potato's great genetic diversity needs to be maintained for future agricultural applications and can be preserved at ultra-low temperatures. To decipher detailed physiological processes, the aim of the study was to analyze the regrowth in 28 gene bank accessions and to reveal metabolite changes in a subset of four accessions that showed pronounced differences after shoot tip cryopreservation using DMSO droplet freezing and PVS3 droplet vitrification. Regrowth varied in all 28 genotypes ranging from 5% (‘Kagiri’) to 100% (‘Karakter’) and was higher after PVS3 droplet vitrification (71 ± 19%) than after cryopreservation using DMSO (54 ± 17%). Sucrose, glucose, and fructose were analyzed and showed significant increases after pre-culture in combination with PVS3 or DMSO and liquid nitrogen treatment and were reduced during regeneration. In contrast, adenosine triphosphate (ATP) reached its minimum concentration after cryoprotection and liquid nitrogen treatment and recovered most quickly after PVS3 droplet vitrification. A shortening of the explant pre-culture period reduced dramatically the regrowth after PVS3 vitrification. However, correlations between the shoot tip regrowth and sugar concentration were absent and significant at a low extent with ATP (r = 0.4, P < 0.01). Interestingly, several sub-cultivations of the donor plants from the previous stock affected negatively the regrowth. In conclusion, the cryopreservation protocol, genotypes, pre-culture period and number of sub-cultures affect the regrowth ability of explants, which was best estimated by the ATP concentration after low-temperature treatment. Due to the superior performance of PVS3, the routine potato cryopreservation at the Gatersleben gene bank was changed to PVS3 droplet vitrification.

The Balkan collections 1941-1942 of Hans Stubbe in the Gatersleben Gene Bank

The German Federal Gene Bank at the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) in Gatersleben comprises ca. 148 000 accessions of crop plants and their wild relatives. Among these, material from Albania and Greece is represented with ca. 1100 and more than 2700 accessions, respectively. IPK’s collection of Albanian germplasm is the world’s largest collection, while IPK’s Greek germplasm collection is the third largest holding of Greek crops and their wild relatives. The largest part of this material (ca. 200 and 1600 accessions from Albania and Greece, respectively) originates from two collecting expeditions carried out by Hans Stubbe, the founder of the Institute for Cultivated Plant Research, and other German collectors during the Second World War, in 1941 (ca. 700 accessions) and 1942 (ca. 1100 accessions). Stubbe’s expeditions are described with respect to the regions visited, species collected, plus a comparison between the original collections and their present state in the IPK Gene Bank is provided. A formal scientific report about the results of these expeditions had never been published before. The material from these expeditions can be freely requested from the IPK Gene Bank, after signing a Material Transfer Agreement.

Analysis of wheat disease resistance data originating from screenings of Gatersleben genebank accessions during 1933 and 1992

Series of 10,348 accessions belonging to 21 species (hexaploid, tetraploid, diploid) of the genus Triticum and 489 accessions belonging to 20 species of the genus Aegilops were scored for disease resistance during a period of 60 years. Tests were performed at the seedling stage for powdery mildew (Erysiphe graminis DC. f. sp. tritici March.), leaf rust (Puccinia recondita Rob. ex Desm. f. sp. tritici Erikss.), stripe rust (Puccinia striiformis West. f. sp. tritici Erikss.) and eyespot (Pseudocercosporella herpotrichoides (Fron.) Deight.) but also at the adult plant stage considering powdery mildew, leaf rust, stripe rust, eyespot and glume blotch (Septoria nodorum Berk.). About 150,000 disease scores recorded on index cards using different scoring scales were transferred to the computer, converted into a 1–9 scale and used to summarise the results. Within the genus Triticum 20% of the material analysed was classified as heterogeneous. For the accessions without detectable segregation a large variability for resistance/susceptibility was detected. At the adult plant stage resistant accessions without visible infections were identified for all diseases. The percentages of resistant accessions at that growth stage were always higher than the ones found in the material tested at the seedling stage. The probability for finding resistant material was shown to be highest in the diploid species ( > 50%) but decreased with increasing ploidy level to about 10% in the hexaploids. For Aegilops it was shown that most of the accessions were homogeneous and highly resistant against powdery mildew (seedling and adult plant stage), leaf rust (adult plant stage) and eyespot (seedling and adult plant stage/natural infection). The data obtained for the individual accessions are available via Internet (http://www.ipk-gatersleben.de).

Analysis of Wheat Disease Resistance Data Originating from Screenings of Gatersleben Genebank Accessions during 1933 and 1992

Analysis of Wheat Disease Resistance Data Originating from Screenings of Gatersleben Genebank Accessions during 1933 and 1992

Gliadin Electrophoretic Analysis of the Genetic Integrity of Wheat (Triticum aestivum L.) Accessions After Frequent Seed Reproductions

A standard electrophoretic method for wheat cultivar identification was used on single seeds to analyse the genetic integrity of 11 wheat (Triticum aestivum L.) accessions after up to 24 seed reproductions in the Gatersleben genebank. It was clearly demonstrated that the gliadin pattern of single seeds can be used to analyse the genotype composition of wheat accessions. Stability of electrophoretic banding patterns was detected in eight accessions. Very week genetic drift was observed in three accessions. Our investigations confirm experiences of the successful utilisation of protein markers for cultivar verification and genetic integrity testing and demonstrate the high standard of wheat accessions maintenance in the Gatersleben genebank.

Taxonomic status and geographic provenance of germplasm accessions in the Solanum nigrum L. complex: AFLP data

Amplified Fragment Length Polymorphisms (AFLPs) were employed within the taxonomically difficult Solanum nigrum L. complex in order to characterize the genetic diversity present in a collection of the Gatersleben Genebank, to classify taxonomically unknown material, and to correlate the clustering of the examined accessions with their geographic origin. The results from AFLP analyses using two primer combinations on 44 entries from five species led to the detection of four major clusters, simultaneously uncovering significant differences in the levels of genetic diversity within or between species. S. americanumexhibited the highest infraspecific variation despite close geographic origins, simultaneously being placed in a clearly separated cluster in comparison to the other examined species of the complex. In addition, these other species showed even less interspecific variation than was found at the infraspecific level in S. americanum. In terms of taxonomy, the application of AFLPs helped in the classification of 13 black nightshade accessions formerly only listed as Solanum sp. This also was confirmed by morphological determination. Furthermore, one accession formerly classified as S. physalifolium var. nitidibaccatum i) clustered with AFLPs and ii) was identified morphologically as S. villosum. Contradictory classifications remain for two further entries from the same species, found within the S. nigrum cluster after AFLP analyses, while belonging to S. physalifolium var. nitidibaccatum according to herbarium specimen. Finally, as indicated by the information on provenance in geographically separated subclusters in S. americanum and partially in S. villosum, clues on the currently unknown origin of accessions from the genebank seem feasible by AFLP data.

Eyespot resistance in wheat ×Aegilops kotschyi backcross lines

AbstractIn wheat, eyespot caused by PseudoCercosporella herpotrichoides, is one of the main foot‐rot diseases. Yield losses up to 40% occur in some years. Plant protection by fungicide application is possible, but a better way is through resistance breeding. Two resistance sources are currently used: Aegilops ventricosa and the old French variety ‘Cappelle Desprez’. A new source of resistance has been found in the accession AE120 of Ae. kotschyi from the Gatersleben gene bank with the genome constitution UUSvSv. This accession has been crossed and backcrossed twice to susceptible wheat varieties, and in each generation, plants with a relatively high level of resistance have been selected. From this material, lines have been developed and tested in F6 to F8. Finally, several lines could be classified as moderately resistant, such as the French variety ‘Cappelle Desprez’ after resistance determination during milk ripeness (DC75). No line reached the high resistance level achieved with Pch‐1 from Ae. ventricosa. The yield of these lines under infection conditions was higher compared with ‘Cappelle Desprez’. The line 6018‐96‐3 showed a high yield of 64.3 dt/ha compared with 59.6 dt/ha, on the average, in combination with the best expression of eyespot resistance in the adult growth stage over 3 years.

Molecular characterization of the genetic integrity of wheat (Triticum aestivum L.) germplasm after long-term maintenance

The genetic identity of eight wheat (Triticum aestivum L.) accessions maintained in the Gatersleben genebank and regenerated up to 24 times was studied by using wheat microsatellite markers (WMS). It was demonstrated that WMS can be used to analyze bulks of seeds stored more than 50 years in a seed reference collection at room temperature. No contamination due to foreign pollen or incorrect handling during the multiplication cycles was discovered. For one accession (TRI 4599) genetic drift was observed, whereas for TRI 249 a heterogenous situation for two markers was maintained over the years. We were able to show that microsatellites can be used as a simple and reliable marker system for the verification of the integrity and genetic stability of genebank accessions.

Chemotypes of Fennel (Foeniculum vulgare Mill.)

The essential seed oils of the fennel collection (42 accessions) of the Gatersleben gene bank, which were obtained by hexane extraction, have been examined by GC. In the compositions of the oils four chemotypes could be distinguished, which are differentiated by the presence or absence of the main compounds (E)-anethole and methyl chavicol, respectively.

An interim report on a long term storage experiment on rye (Secale cereale L.) under a range of temperatures and atmospheres

A long term seed storage experiment with rye was started in 1978 in the Gatersleben genebank. Seeds of 3.7 and 5.5% moisture content were kept at −15, 0 and 10 °C in hermetically sealed glasses filled with air, CO2, N2, and also evacuated. The initial germination was 72% and germination was tested after 1, 5, 15 and 17 years of storage. After 17 years at −15 °C the smallest losses in germination and smallest interactions with the gas atmosphere were observed. At 0 and 10 °C there were greater, but variable losses in germination and inconsistent interactions with the gas atmosphere. Generally, air promoted and N2 reduced germination loss.

Variation of cultivated flax (Linum usitatissimum L. subsp.usitatissimum) and its wild progenitor pale flax (subsp.angustifolium (Huds.) Thell.)

The domestication of cultivated flax (Linum usitatissimum L. subsp.usitatissimum) is briefly discussed. Using data documented as a matter of routine in genebank work, 63 accessions of cultivated flax from the flax germplasm collection of the Gatersleben Genebank are compared with 73 accessions of its wild progenitor pale flax (subsp.angustifolium (Huds.) Thell.), which have been observed in systematic field trials. Range of variation, genetically based variation, heritability and correlation of several characters are considered, especially with respect to the influence of domestication. Cultivated flax shows higher variation in the characters of generative plant parts, while pale flax varies more in the vegetative parts of the plant. The character correlations are similar in both subspecies. Of the 29 characters studied in pale flax the parameters describing tillering, height of plant, weight of seeds, width of petals and width of leaves are especially suitable for distinguishing between different accessions. In spite of the high heritabilities of most of the characters, the influence of the environment is significant in most cases.

Preliminary results of a screening for GA3 response in wheats of the Gatersleben gene bank

A total of 700 wheat accessions of the Gatersleben gene bank were screened for gibberellic acid insensitivity genes (Gai) by a modified method. It was found, that 77 hexaploid and 5 tetraploid wheats were GA3-insensitive. The probable origin of theGai-genes is discussed.