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Hannover, Germany

The suitability of induced mutagenesis and polyploidization of Hydrangea macrophylla to be incorporated in breeding programs was investigated. For mutagenesis nodal explants in vitro of variety 'Blaumeise' were irradiated with X-rays (5, 10, 20 and 30 Gy). The lethal dose of 50% was between 20 and 30 Gy. Irradiated plants were transferred to the greenhouse. New phenotypic traits like dwarfism, deformed leaves or black stems were observed. Polyploidization was carried out on nodal explants in vitro, too. Plant material was from the diploid varieties 'Adria' and 'Libelle' as well as from the triploid varieties 'Blaumeise' and 'Nachtigall'. For mitosis inhibition colchicine and trifluralin were used. After treatment with colchicine only four ploidy chimeric plants were found. The effectiveness of trifluralin was much better. Already after treatment with 0.001% trifluralin polyploidized plants were received. Hexaploid plants showed a strong dwarfism and deformed leaves. By contrast, tetraploid plants were attractive like the diploid origins. The flow cytometry enabled rapid ploidy estimation and after the fluorescence in situ hybridization with gene sequences of 5S and 18/25S rDNA the karyotypes were characterized. Each ribosomal DNA sequence used was localized one time on the haploid genome on different chromosomes. The relevance of mutagenesis and polyploidization for creation of pre-breeding material will be discussed. Especially the utilization of tetraploid hydrangeas seems to be a useful tool for the development of new hydrangea varieties.

Rukavina I.,Hrvatski centar za poljoprivredu | Maric S.,Sveuciliste Josipa Jurja Strossmayera u Osijeku | Guberac V.,Sveuciliste Josipa Jurja Strossmayera u Osijeku | Cupic T.,Poljoprivredni Institute Osijek | Tepper C.,Bundessortenamt
Poljoprivreda | Year: 2012

Glutenins loci were used for variability estimation in 50 varieties of hexaploid winter wheat originated from Croatian breeding centres. Polyacrylamide gel electrophoresis (PAGE) in presence of sodium dodecyl sulphate (SDS) was used for determination of high molecular weight glutenins (HMW-GS). Number of allels per loci ranged from 3 at Glu-A1 to 5 at Glu-B1 and Glu-D1, the average number of allels was 4.33. The highest genetic diversity was found at loci Glu-B1 (He=0.687). The most frequent subunit at loci Glu-A1 was 2* (56%). At loci Glu-B1 the most common combination of subunits was 7+8 with 40%, and at loci Glu-D1 5+10 with 68%. The study also defines high quality varieties with largest number of Glu-scores. The results attained from this study allow further development of specific breeding programs for winter wheat quality improvement and improvers creation.

Laidig F.,Bundessortenamt | Piepho H.-P.,University of Hohenheim | Drobek T.,Bundessortenamt | Meyer U.,Bundessortenamt
Theoretical and Applied Genetics | Year: 2014

Key message: Yield progress in major German crops is generated mostly due to genetic improvement over the last 30 years. Comparison of trial-station with on-farm yield reveals considerable gaps that are widening over time.Abstract: Yield progress of newly released varieties for 12 crops from official German trials over the period 1983 until 2012 was analysed to assess their value for cultivation and use (VCU). We paid special attention to dissect progress into a genetic and a non-genetic (agronomic) trend in order to quantify the contribution made by new varieties and by agronomic factors. In this study, we apply mixed models including regression components for genetic and agronomic trends. Ageing effects, depending on the difference of the actual testing year and the first year of testing of a particular variety, were estimated from the difference of fungicide and non-fungicide-treated trial pairs. Significant yield losses were found in all cereal crops due to assumed ageing effects. We compared national on-farm with official VCU trial yields with particular focus on whether gaps are widening over time. Results indicated a significant widening over time. In order to facilitate comparisons of results across crops, we calculated percent rates based on 1983 yield levels obtained from regression estimates. Most of the yield progress was generated by genetic improvement, and was linear showing no levelling-off. Ageing and selection effects need to be taken into account, because they may lead to overestimation of genetic trends. This study showed that contribution of agronomic factors is of minor importance in overall yield progress. © 2014, The Author(s).

Reid A.,SASA | Hof L.,Naktuinbouw | Felix G.,SASA | Rucker B.,Bundessortenamt | And 6 more authors.
Euphytica | Year: 2011

The European Union Common Catalogue (EUCC) for potato contains over 1000 varieties. Each year member states add varieties to the list after they have undergone Distinctness, Uniformity and Stability (DUS) testing according to international guidelines. A rapid and robust method for variety identification to aid the management and maintenance of existing variety collections and for the screening of new candidate varieties would therefore be a highly useful tool for DUS testing stations. A database containing key morphological characteristics and microsatellite data was constructed for varieties on the 2006 list of the EUCC for potato. Rules for scoring SSR markers in different laboratories were established to allow a harmonized scoring of markers. Almost all varieties (99.5%) were shown to have unique molecular profiles and in pair wise comparisons 99.99% of all variety pairs could be distinguished. This clearly shows the versatility of the markers and database for identifying potato samples. © 2011 Crown Copyright.

Miedaner T.,University of Hohenheim | Mirdita V.,University of Hohenheim | Rodemann B.,Julius Kuehn Institute Federal Research Center for Cultivated Plants | Drobeck T.,Bundessortenamt | Rentel D.,Bundessortenamt
Plant Breeding | Year: 2010

Ergot caused by Claviceps purpurea (Fr.) Tul. is a serious threat to rye (Secale cereale L.) cultivation. It produces sclerotia containing a mixture of alkaloids toxic to animals and humans. For improving ergot resistance in rye a reliable field testing with a minimal disturbance by pollen transfer between plots is indispensable. We evaluated 85 rye cultivars of four types of cultivar (population, synthetic, and hybrid cultivars, hybrids blended with 10% population rye) under inoculation in 3 years (2005, 2006 and 2007) and analysed ergot incidence (% of affected heads) and ergot severity (% of sclerotia in grain by weight) at nine and ten environments (location × year combinations), respectively. Cultivar types were separated by border plots and each entry was additionally surrounded by four border plots of similar size (3-8 m2) in a chess-board design. Disease level ranged from 10-27% affected heads and 0.7-2.6% sclerotia in grain in individual environments. Both, cultivar type and cultivars showed significant (P = 0.01) variation for both traits, interactions with environment were also significant (P = 0.01). Population cultivars had less than half the disease level than the other types of cultivar for both traits. Synthetic, hybrid, and blended hybrid cultivars did on average not differ significantly from each other. Blending had an ergot-reducing effect only for the more susceptible entries. The best two hybrid cultivars showed an ergot reaction similar to some population cultivars. However, the best population cultivar still had only half the amount of sclerotia in grain than the best hybrid cultivar (0.37% vs. 0.89%). Ergot incidence and ergot severity were highly (P = 0.01) correlated. We conclude that a good genotypic differentiation among rye cultivars is achievable by field inoculation of Claviceps purpurea across years with this design and testing within national listing trials is feasible. © 2009 Blackwell Verlag GmbH.

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