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Munsch M.A.,Universitatstrasse 2 | Stamp P.,Universitatstrasse 2 | Christov N.K.,Agrobioinstitute Dragan Tsankov Blvd | Foueillassar X.M.,Arvalis Institute du Vegetal | And 3 more authors.
Crop Science | Year: 2010

Maize (Zea mays L.) Plus-Hybrids are a blend of cytoplasmic malesterile (CMS) hybrids and unrelated male-fertile hybrids ensuring pollination of the whole stand. Combining potential benefits of male sterility (CMS effect) and allopollination (xenia effect), they often outperform the corresponding male-fertile sib-pollinated hybrids in terms of yield. The combining abilities of five CMS hybrids and eight pollinators were investigated in a factorial split-plot design in 12 environments in four countries and two years. The plant material from different breeders represented the three types of malesterile cytoplasm. Plus-Hybrids increased grain yield, on average, by 10% or more and by up to 20% in specific environments. Three highly responsive CMS hybrids and four generally good pollinators were identified. The Plus-Hybrid effect affected both yield components, CMS leading mainly to a higher number of kernels (KN) and the xenia effect mainly to an increase in the thousand kernel weight (TKW). Despite some differences in the response of the three types of CMS, the effect of the cytoplasm was not significant. While the CMS effect depended strongly on environment, the xenia was consistent in all environments but its extent varied. As well as increasing yield, we can expect that Plus-Hybrids can make a large contribution to the coexistence of transgenic and conventional maize by biocontainment, that is, eliminating or reducing the release of transgenic pollen in Bacillus thuringiensis (Bt) maize or herbicide-tolerant (HT) maize. © Crop Science Society of America.


Njontie C.,Julius Kuhn Institute | Foueillassar X.,ARVALIS Institute du Vegetal | Christov N.K.,Agrobioinstitute Dragan Tsankov Blvd. | Husken A.,Julius Kuhn Institute
Euphytica | Year: 2011

Recently, the introduction of GM maize in agricultural production in the EU and elsewhere has raised the issue of adventitious presence of GM seeds in conventional seed lots. Adventitious presence may occur in all arable farming, and at any step in the production of seeds or grain, or in processing of harvested product in the food/feed chain. As of today, there are no official thresholds governing the adventitious presence of GM seeds in conventional seed lots in Europe. However, it is assumed that GM admixture in seed lots could have a considerable influence on the level of adventitious presence in the non-GM harvested product. The experiments highlighted in this paper aim at the consequences of adventitious presence of GM maize seeds in conventional seed lots. It is shown for varieties belonging to the same maturity group that the final GM rate (% seeds) in the harvest product is nearly same as the initial seed admixture (% seeds). This corresponds to Hardy-Weinberg expectations. The variation depends mainly on the flowering coincidence, the site and climatic conditions. In cases where the admixed seeds are of different maturity group, the level of cross-pollination in the harvest product is reduced. Furthermore a comparison between the visual GM seed detection and real-time PCR detection was done. It is evident that the result of the real-time PCR detection method has a more variable uncertainty associated with its results than the visual seed testing method. The accuracy of prediction from % GM seed to % GM DNA depends on the reference material used for calibration curves. © 2011 Springer Science+Business Media B.V.


Ganeva G.,Bulgarian Academy of Science | Korzun V.,KWS LOCHOW GMBH | Landjeva S.,Bulgarian Academy of Science | Popova Z.,Institute For Plant Genetic Resources Kmalkov | Christov N.K.,Agrobioinstitute Dragan Tsankov Blvd.
Genetic Resources and Crop Evolution | Year: 2010

The genetic diversity in a Triticum durum Desf. collection, consisting of 102 Bulgarian landraces, nine Bulgarian and 25 introduced cultivars was studied using 14 highly polymorphic microsatellite markers. A total of 100 alleles were identified, with an average of 7. 14 alleles per marker. The gene diversity values (He) of the markers for the total samples ranged from 0.23 (WMS357 and WMS631) to 0.77 (WMS46), with an average of 0.52. Within the landraces that were collected from 18 sites in Southern Bulgaria showed 2-11 alleles per locus with an average of 6.07. The microsatellite analysis suggests that the genetic diversity among landraces is lower compared to the diversity levels for durum wheat in countries close to the main centers of wheat domestication. Breeding activities have caused significant reduction of the allelic polymorphism, elimination of rare alleles, and increase in the number of common alleles and the frequency of dominating alleles. © Springer Science+Business Media B.V. 2009.


Marchev A.,Bulgarian Academy of Science | Georgiev V.,Bulgarian Academy of Science | Ivanov I.,Bulgarian Academy of Science | Badjakov I.,Agrobioinstitute Dragan Tsankov Blvd | Pavlov A.,Bulgarian Academy of Science
Biotechnology Letters | Year: 2011

Hairy root cultures of Salvia tomentosa were initiated by transformation with Agrobacterium rhizogenes. To prevent necrosis in the explants and to protect young hairy roots, Amberlite XAD-4 resin, in combination with a temporary immersion cultivation system, was applied. HPLC analyzes showed that the resin adsorbed more than 93% of the released phenolic acids and 100% of the released flavonoids. The decreased content of the released phenolics significantly reduced their destructive effects on the plant tissues, prevented, and speeded up the appearance of hairy roots. © 2011 Springer Science+Business Media B.V.


Berkov S.,University of Barcelona | Berkov S.,Agrobioinstitute Dragan Tsankov Blvd. | Georgieva L.,Agrobioinstitute Dragan Tsankov Blvd. | Kondakova V.,Agrobioinstitute Dragan Tsankov Blvd. | And 4 more authors.
Biochemical Systematics and Ecology | Year: 2013

Leucojum aestivum, an industrial source of the acetylcholinesterase inhibitor galanthamine, shows a great chemodiversity in its alkaloid synthesis. Samples from various geographically distinct populations from Bulgaria and the Balearic Islands were studied by GC-MS. The alkaloid pattern of the plants of L. aestivum (subsp. pulchellum) from the Balearic Islands were dominated by crinine type compounds. Populations of homolycorine chemotype were distributed along the Danube river in the north part of Bulgaria, which is separated from the south part by the Balkan mountains. Populations with high accumulation of lycorine were found in East Bulgaria near the sea coast, while the south populations were dominated by galanthamine type synthesis. The average of the galanthamine content was found to vary from 0.003 to 0.08% (referred to dry weight) in the north, and up to 0.42% in the southern Bulgarian populations. Some individuals showed up to 0.65% galanthamine. The galanthamine content of the plants from the Balearic island was 0.1% of DW. The galanthamine percentage in the total alkaloid mixture ranged from 0.2 to 95% of the total alkaloids. Our study demonstrated that the geographic isolation of the populations of L. aestivum has led to divergation in the alkaloid biosynthesis and consequently to the occurrence of different chemotypes. This chemodiversity in both alkaloid patterns and galanthamine content provides an opportunity for further selection work toward a galanthamine-rich crop, on the one hand, and makes the species an excellent biological system for molecular studies leading to further improvement of the galanthamine production, which is a valuable alkaloid used in medicine for the treatment of Alzheimer's disease. © 2012 Elsevier Ltd.


Georgieva T.,Agrobioinstitute Dragan Tsankov Blvd | Georgieva T.,Michigan Technological University | Christov N.K.,Agrobioinstitute Dragan Tsankov Blvd | Djilianov D.,Agrobioinstitute Dragan Tsankov Blvd
Acta Physiologiae Plantarum | Year: 2012

The Balkan endemic plant species Haberlea rhodopensis belongs to the group of resurrection plants. The members of this small group of angiosperms tolerate extreme dehydration of their vegetative tissues, which are able to recover very rapidly upon rehydration. In this respect, resurrection plants are a unique model intensively studied to reveal the secrets of desiccation tolerance. To date, the knowledge on the molecular biology of H. rhodopensis is very limited. Here, we report on the application of a cDNA-AFLP analysis to examine gene expression in leaves of Haberlea during dehydration. Twenty transcripts among 33 sequenced cDNA fragments appear to be involved in energy metabolism, transport, cell-wall biogenesis, signal transduction, or are probably transcription regulators according to their putative function. Expression patterns of two up-regulated (HrhDR8, HrhDR35) and two down-regulated (HrhDR6, HrhDR25) transcripts were verified by sqRT-PCR analysis at different stages of water stress. The results demonstrated that two up-regulated transcripts HrhDR8 and HrhDR35 encoding putative succinate-dehydrogenase and xyloglucan endotransglucosylase/hydrolase (XTH), respectively, were induced during early stage of dehydration, persist in desiccated state, and subsequent rehydration of Haberlea. Their possible involvement in drought tolerance is discussed. © 2011 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.


Rusanov K.,Agrobioinstitute Dragan Tsankov Blvd | Kovacheva N.,Essential Medical | Rusanova M.,Agrobioinstitute Dragan Tsankov Blvd | Atanassov I.,Agrobioinstitute Dragan Tsankov Blvd
European Food Research and Technology | Year: 2012

Methyl eugenol (ME) is a naturally occurring carcinogenic compound found in a number of essential oils including rose oil distilled from Rosa damascena Mill flowers. In the current study, we evaluate the effect of flower harvesting practices on the ME content in the produced rose oil. The obtained results show nearly twice reduction in ME content in the rose oil distilled from petals of full-blown flowers. At the same time, GC/MS analysis of rose oils distilled from stages 3 and 4 rose flower buds (flower buds prior opening of petals) showed more than 5 times ME reduction and preservation of the relative content of the major rose oil compounds. Moreover, the comparative study of rose flower yield and rose oil content of rose buds and full-blown flowers showed that harvesting of rose flower buds results in above three times increase in the formed flower buds from the studied rose plants and more than twice increase in the rose flower and rose oil yields for the same rose plantation areas. The overall results from this study allow us to propose a change in the traditional full-blown rose flower harvesting to harvesting of rose flower buds at stages 3 and 4 during the entire flowering period. © 2012 Springer-Verlag.


Tsonev S.,Agrobioinstitute Dragan Tsankov Blvd. | Todorovska E.G.,Agrobioinstitute Dragan Tsankov Blvd. | Christov N.K.,Agrobioinstitute Dragan Tsankov Blvd.
Bulgarian Journal of Agricultural Science | Year: 2015

During the last decade the number of the IDP markers and their utilization in laboratory practice are constantly growing. Their combination with SSR markers can facilitate saturation of genetic maps. The main disadvantage of both types of markers is the low degree of automation. Although, SSR and IDP markers share similar properties and way of detection, information on multiplexing both types of markers in a single PCR reaction has not been described. Therefore, the present study aimed at increased throughput of the PCR marker assays on a capillary sequencer by simultaneous amplification and fluorescent labeling of SSRs and redundant set of IDP markers in a single closed tube format. Ninety six co-dominant markers, with allele sizes suitable for multiplexing with SSRs, were selected from a public set of 1229 maize IDP markers. Twenty seven of them were polymorphic between the parental lines of a double-haploid population derived from F1 cross of a mutant maize inbred with its progenitor line. Seventeen of the polymorphic IDPs together with nineteen SSRs were used to develop a versatile fluorescence- based multiplexing assay for combined genotyping on capillary electrophoresis systems. Both IDP and SSR markers were successfully co-amplified and fluorescently labeled in 11 multiplex PCR reactions that included up to 4 primer pairs. The robustness of the method was validated by genotyping and map construction in the DH mapping population. The proposed multiplexing method will provide advantages for enrichment of target regions in fine mapping and map-based cloning projects as well as in marker assisted selection. With the increased availability of genome information and genome sequences of multiple varieties, the method could be successfully applied in other model and crop plant species. © 2015, National Centre for Agrarian Sciences. All rights reserved.


Rusanov K.,Agrobioinstitute Dragan Tsankov Blvd. | Kovacheva N.,Essential Medical | Rusanova M.,Agrobioinstitute Dragan Tsankov Blvd. | Atanassov I.,Agrobioinstitute Dragan Tsankov Blvd.
Food Chemistry | Year: 2011

Industrial cultivation of Rosa damascena and rose oil production is a centuries-old industry based on well-established traditional hand-picking of rose flowers. Here the traditional rose harvesting practices were evaluated through GC/MS analysis of the volatile compounds accumulation in R. damascena flowers at eight different developmental stages, flower buds with arrested development and flowers collected at six daytime points related to flower picking. The accumulation of 80 out of 100 volatile compounds was significantly influenced by the stage of flower development while 62 out of 103 compounds were significantly influenced by the daytime period of flower collection. Principal component analysis showed close clustering of the flower developmental stages and daytime periods preferable for flower harvesting and production of high quality and quantity of rose oil. Taken together the obtained results provide further support to the currently applied traditional rose flower harvesting practices. The possible applications of more precise flower harvesting for fine modulation of rose oil composition and reduction levels of the unwanted compound methyl eugenol are discussed. © 2011 Elsevier Ltd. All rights reserved.


Milusheva S.,Bulgarian Fruit Growing Institute | Bozhkova V.,Bulgarian Fruit Growing Institute | Kamenova I.,Agrobioinstitute Dragan Tsankov Blvd.
Acta Horticulturae | Year: 2015

The aim of this study was to evaluate the reaction of plum cultivar 'Jojo' to Plum pox virus (PPV) infection by combination of biological indexing with PPV-M, -D and -Rec strain isolates and field observations in Bulgarian commercial orchards, planted with 'Jojo', under the agro-biological conditions of three locations of the Plovdiv region. Development of visual symptoms on the field grown trees' leaves and fruits was monitored during three successive vegetative cycles (2010-2012). PPV presence in plant tissues was detected by enzyme-linked immunosorbent assay (ELISA) and immune capture-reverse transcription-polymerase chain reaction (IC-RT-PCR). The biological indexing experiment showed that initially small chlorotic spots developed on the leaves of the inoculated plants that turned brownish (hypersensitive reaction) later on, followed by falling of the necrotic tissues. In the field survey, similar symptoms of hypersensitivity were observed on the leaves of some 'Jojo' trees. Leaf samples from plants that manifested hypersensitive reaction (the inoculated plants and field growing trees) reacted negative with antiserums against PPV in ELISA and no amplification was obtained in IC-RT-PCR with the primer pair P1/P2 used. Several of the trees grown in the field showed some viruslike leaf symptoms, during the third vegetative period. Samples collected from these trees reacted negative for PPV in ELISA and none of the samples tested by IC-RT-PCR produced PPV-specific PCR products. However, the symptomatic trees reacted positive with antiserum against Prunus necroticc ring spot virus (PNRSV). No symptoms on the fruits of the inspected 'Jojo' trees were recorded. The results obtained suggest that 'Jojo' cultivar could be resistant to PPV infection, both in the experimental biological indexing and under the agro-biological conditions of the Plovdiv region of Bulgaria.

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