Browsing by Author "Rohde, W."

Now showing 1 - 8 of 8
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    Cuticular wax composition in Cocos nucifera L.: physicochemical analysis of wax components and mapping of their QTLs onto the coconut molecular linkage map
    (2009) Riedel, M.; Riederer, M.; Becker, D.; Herran, A.; Kullaya, A.; Pena-Rodriguez, L.; Arana-Lopez, G.; Billotte, N.; Rohde, W.; Sniady, V.; Ritter, E.
    Cuticular waxes were extracted from the leaves of a coconut mapping population generated by the controlled cross of an East African Tall and a Rennell Island Tall genotype for the construction of molecular linkage maps. The wax composition was analyzed by capillary gas chromatography/mass spectrometry, and for eight of the wax compounds, their absolute and relative amounts were determined. As reported previously for a different coconut ecotype (Malayan Yellow Dwarf), lupeol methyl ether, isoskimmiwallin, and skimmiwallin were identified as the major components of coconut cuticular wax. The additional compounds were characterized as 3-β-methoxy lupane (lupane methyl ether), lupeol and the acetic acid esters of lupeol, skimmiwallinol, and isoskimmiwallinol, respectively. Minor, nonidentified compounds amounted to some 5% of total wax content and included triterpenoids, sterols, primary alcohols, and fatty acids. The variation detected for parents and progeny with respect to the wax components allowed quantitative trait locus (QTL) analyses for their biosynthetic pathways. A total of 46 QTLs could be mapped onto the coconut linkage map which was extended by amplified fragment length polymorphism and single sequence repeat markers into a high density map with more than 1,000 mapped DNA markers. Several colocated QTLs for different traits were detected reflecting the observed correlations among characters.
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    Detection and Molecular Characterization of Phytoplasma associated with Lethal Yellowing Disease of Coconut Palms in Cuba
    (2002) Llauger, R.; Becker, D.; Cueto, J.; Peralta, E.; Gonzalez, V.; Rodriguez, M.; Rohde, W.
    Lethal Yellowing (LY) disease of coconut palm (Cocos nucifera L.) in Cuba has been reported since the end of the 19th century. In order to ascertain the presence of phytoplasmas associated with this disease, leaf samples were taken from plants showing typical disease symptoms and assayed for the LY agent by the polymerase chain reaction (PCR) using LY-specific primers. Selected PCR amplification products were cloned, sequenced and compared to that of a Mexican LY isolate from the Yucata´n region. The results obtained confirm the presence of LY phytoplasma in Cuba. Cuban and Mexican isolates show an overall high degree of sequence similarity with occasional point mutations and small deletions or insertions. Based on these identified genetic differences, LY isolates from the Havana and the Yucata´n region cluster together and apart from isolates originating at Maisı´ in eastern Cuba.
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    Linkage mapping and QTL analysis in coconut (Cocos nucifera L.)
    (2000) Herran, A.; Estioko, L.; Becker, D.; Rodriguez, M.J.B.; Rohde, W.; Ritter, E.
    Different DNA marker types were used to construct linkage maps in coconut (Cocos nucifera L.; 2n = 32) for the two parents of the cross Malayan Yellow Dwarf (MYD) × Laguna Tall (LAGT). A total of 382 markers was sufficient to generate 16 linkage groups for each parent. The total genome length corresponded to 2226 cM for the LAGT map and 1266 cM for the MYD map with 4–32 markers per linkage group. Common markers allowed the association of 9 linkage groups for the two parents MYD and LAGT. QTL analysis for the trait early germination identified six loci. These QTLs correlate with early flowering and yield, representing characters which are important in coconut breeding. The co-segregation of markers with these QTLs provides the first opportunity for marker-assisted selection in coconut breeding programmes.
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    Localisation of coconut foliar decay virus in coconut palm
    (2007-02-08) Randles, J.W.; Hanold, D.; Rohde, W.; Morin, P.; Miller, D.C.
    Coconut foliar decay virus (CFDV) occurs at a very low concentration in coconut palm. A 1203 nucleotide segment of the scquenced encapsulated circular single-stranded 1291 nucleotide CFDV-DNA has been amplified and transcribed for use as a p cDNA probe for the virus. A rapid method for the extraction of DNA from coconut palm has been devised for a dot-blot hybridisation assay using this probe. An alternative non-radioactive probe has also been developed for future use in CFDV diagnosis. CFDV-DNA was shown to be distributed unevenly in a range of infected palms, necessitating the use of multiple sampling to reliably detect infection in diagnostic tests. Viral DNA was detected in symptomatic and asymptomatic palms of both high and low susceptibility, in disease-free tolerant cultivars. and in palms in remission from disease. Within the same palm, detectability of viral DNA varied little within leaflets, but varied more within and between fronds, CFDV-DNA was detected 6-8 months after insect-mediated inoculation, and symptoms generally appeared after another 1-4 months. In sun hybridisation of rachis tissue showed localisation of DNA within the phloem. bin its distribution in the phloem was uneven. CFDV-DNA was detected in tissue adjacent to and within necrotic zones which develop into the petiolar lesions associated with the disease-specific collapse of fronds. Virus was detected in the body of the insect vector, and, where its distribution could be resolved, in the abdomen rather than the head.
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    Microsatellite-based high density linkage map in oil palm (Elaeis guineensis Jacq.)
    (Springer-Verlag, 2007) Billotte, N.; Marseillac, N.; Risterucci, A.M.; Adon, B.; Brottier, P.; Baurens, F.C.; Singh, R.; Herran, A.; Asmady, H.; Billot, C.; Amblard, P.; Durand Gasselin, T.; Courtois, B.; Asmono, D.; Cheah, S.C.; Rohde, W.; Ritter, E.; Charrier, A.
    A microsatellite-based high-density linkage map for oil palm (Elaeis guinensis Jacq.) was constructed from a cross between two heterozygous parents, a tenera palm from the La Me population (LM2T) and a dura palm from the Deli population (DA10D). A set of 390 simple sequence repeat (SSR) markers was developed in oil palm from microsatellite-enriched libraries and evaluated for polymorphism along with 21 coconut SSRs. A dense and genome-wide microsatellite framework as well as saturating amplified fragments length polymorphisms (AFLPs) allowed the construction of a linkage map consisting of 255 microsatellites, 688 AFLPs and the locus of the Sh gene, which controls the presence or absence of a shell in the oil palm fruit. An AFLP marker EAgg/M-CAA132 was mapped at 4.7 cM from the Sh locus. The 944 genetic markers were distributed on 16 linkage groups (LGs) and covered 1,743 cM. Our linkage map is the first in oil palm to have 16 independent linkage groups corresponding to the plants 16 homologous chromosome pairs. It is also the only high-density linkage map with as many microsatellite markers in an Arecaceae species and represents an important step towards quantitative trait loci analysis and physical mapping in the E. guineensis species.