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Dresden, Germany

Olbricht K.,Hansabred GmbH and Co. KG | Ulrich D.,Julius Kuhn Institute | Weiss K.,Julius Kuhn Institute | Grafe C.,Julius Kuhn Institute
Journal of Agricultural and Food Chemistry | Year: 2011

Volatile metabolites are a basis for sensory and resistance traits of Fragaria × ananassa. Stability of expression is important for the selection of cultivars. For the first time, the stability of volatiles in a strawberry population after cross-combination of two distinct cultivars ('Mieze Schindler' × 'Elsanta') has been investigated. In this work, environmentally caused variations in the synthesis of 18 volatiles were studied over two years using a model population of 158 clones. The stability varied throughout the F1 seedling population between the two years, defining stable and unstable genotypes with respect to volatile synthesis. Most of the stable genotypes exhibited low values in relative volatile concentration. Merely 6 stable volatiles were detected in the parental cultivars, whereas about 40% of the F1 progeny had up to 11 stable volatiles. Consequently, a higher stability in volatile synthesis can be achieved by breeding. © 2011 American Chemical Society.

Ulrich D.,Julius Kuhn Institute | Ulbricht K.,Hansabred GmbH and Co. KG
Journal of Applied Botany and Food Quality | Year: 2013

Fragaria vesca is the most distributed wild species in the genus Fragaria. Due to this biogeography, a high diversity is to expect. During two harvest seasons, sixteen accessions from different locations from the most eastern habitat at Lake Baikal in Siberia, from Middle and Southern Europe and Northern Europe with Scandinavia and Iceland were investigated as well as two of the three described North American subspecies and three F. vesca cultivars. Five very distinct European F. xananassa cultivars were chosen to serve as a comparison. Beside brix value and acid contents, the aroma patterns including 67 volatile compounds were quantified by stir bar sorptive extraction followed by gas chromatography with mass spectrometric detection. The diversity of important volatiles of Fragaria vesca and F. xananassa is discussed regarding biogeography, domestication, breeding and the so-called funnel effect.

Hofer M.,Julius Kuhn Institute | Drewes-Alwarez R.,FH Dresden | Scheewe P.,FH Dresden | Olbricht K.,Hansabred GmbH and Co. KG
Journal of Berry Research | Year: 2012

Strawberry cultivars in current commercial use have a very narrow genetic base and reduced morphological and genetic diversity that puts them at risk from disease and climate change. Germplasm collections hold examples of the agricultural biodiversity of small berries where they are conserved, characterized and made available to breeders to improve productivity. Phenological evaluations of existing strawberry cultivars provide information for use by breeders in developing cultivars with improved qualities and more diverse genetic background. Leaves, flowers and fruits are the most important morphological descriptors for identification of strawberry cultivars. A comprehensive catalogue of descriptors drawn up by UPOV and IPGRI served as the basis for evaluation of 108 cultivars in a field trial. Each plot consisted of 21 one-year-old plants per genotype and plants were evaluated once with a range of descriptors; 10 of plant and leaf morphology, 7 of the flower and 25 of the fruit. On the basis of this comprehensive evaluation and data analysis, eighteen primary descriptors (plant, leaf, flower and fruit characteristics) independent of cultivation effects were selected for a large screening. Further descriptors for yield, inner fruit quality and disease resistance should be used as secondary descriptors as they are more environmentally influenced. These descriptors were proposed as appropriate primary and secondary descriptors for the European GENBERRY project of the cultivated strawberry (Fragaria x ananassa Duch.). © 2012-IOS Press and the authors. All rights reserved.

Pinker I.,Humboldt University of Berlin | Olbricht K.,Humboldt University of Berlin | Olbricht K.,Hansabred GmbH and Co. KG | Pohlheim F.,Brodberg 38
Acta Horticulturae | Year: 2012

Tunnel effects in 250 years of strawberry breeding history resulted in high performance cultivars with reduction in quality traits connected with flavour and resistances. Genetic resources for important traits are found in wild species such as Fragaria vesca. Mutation breeding of F. vesca up to an octoploid chromosome set is necessary for cross-breeding on a balanced ploidy level with Fragaria ×ananassa Duch. Here, we report on the treatment of axillary seedling buds with amiprofosmethyl (APM) which resulted in sectorial, mericlinal and periclinal ploidy chimeras. Chimeral segregation was performed via callus culture as well as using the generative way (selfing). Callus development and shoot regeneration on selected leaf segments depended on the composition of the medium and varied among the repetitions. The regeneration of adventitious shoots started after six to eight weeks on the induction medium and lasted four to six months. Evaluation of ploidy level was done by e.g., phenotype evaluation, comparison of leaf morphology, stomata measurement, flow cytometry and chromosome counting. From the mutagen treatment to the first fruits of the homohistic regenerates, a period of 18 months was sufficient via callus culture. For generative segregation a time span of 30 months was needed. More tetraploid plants were gained from callus culture than from generative segregation. The auto-tetraploid mutants do not differ in fertility and were used in test crosses with F. ×ananassa resulting in hexaploid hybrids. A second mutagen treatment is being executed to obtain auto-octoploids via polyploidisation of the tetraploid F. vesca.

Olbricht K.,Hansabred GmbH and Co. KG | Ludwig A.,Hansabred GmbH and Co. KG | Ulrich D.,Julius Kuhn Institute | Spangenberg R.,TU Dresden | And 2 more authors.
Acta Horticulturae | Year: 2014

For the first time, the genus of Fragaria was investigated by electron microscopy with regard to epicuticular wax structures and trichome formation on adaxial and abaxial leaf surfaces. In addition, cross-sections and volatile patterns of leaves of several genotypes were analyzed. Distinct differences of epicuticular wax structures among the species were observed on the adaxial but not on the abaxial leaf side. Obviously, epicuticular wax structures are not essential for susceptibility reactions to fungal diseases. Epidermal wall thickness as a reason for resistance to leaf diseases can only be supported for individual examples. Resistance to spider mite (Tetranychus urticae Koch) can be traced back to trichome formation on the abaxial side of the leaf. Additionally, the volatile analysis revealed the release of VOCs as a response to the spider mite attack.

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