The witchesÕ broom disease caused by the fungus Crinipellis perniciosa is the main limiting factor for cocoa production in South America and the Caribbean. In Brazil, this disease affects almost all cocoa-growing regions, causing serious economic, social and ecological damage. The aim of this study was to map genomic regions associated with resistance to C. perniciosa using an F 2 population derived from a cross between ÔScavina-6Õ (resistant) and ÔICS-1Õ (susceptible). The phenotypic index was determined as the average number of vegetative witchesÕ brooms per canopy area of each plant, the witchesÕ brooms were counted and eliminated during six field evaluations between May 1998 and August 1999. A total of 124 random amplified polymorphic DNA (RAPD) and 69 amplified fragment length polymorphism (AFLP) markers were mapped along 25 linkage groups covering 1713 cM of cocoa genome. After employing single factor and composite interval mapping analyses, a major quantitative trait loci (QTL) flanked by the marker AV14.940 was identified in the linkage group 11, explaining almost 35% of the resistance to witchesÕ broom. The present result suggests that this QTL acts as a major dominant component of resistance to this pathogen, with great potential for use in marker-assisted selection procedures in cocoa breeding programmes.

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The thrips, Frankliniella schultzei, and green peach aphid, Myzus persicae, cause direct damage to plants of economic importance and transmit phytoviruses, causing large economic losses. Chemical constituents of essential oils present a wide range of biological activities. The aim of this work was to evaluate insecticidal activity of essential oil from citronella grass, Cymbopogon winterianus, on F. schultzei and M. persicae. This essential oil was obtained by steam distillation and components were identified by GC/FID and GC/MS. A Potter spray tower was used to spray insects with the essential oil. The major constituents are geraniol (28.62%), citronellal (23.62%) and citronellol (17.10%). Essential oil of C. winterianus at 1% (w v -1 ) causes mortality in F. schultzei and M. persicae at 34.3% and 96.9%, respectively. The LC 50 value for M. persicae was 0.36% and LC 90 0.66%. Thus, citronella grass essential oil at 1% (w v -1 ) is more toxic to M. persicae than F. schultzei. This essential oil shows promise for developing pesticides to manage M. persicae. Index terms:Cymbopogon winterianus, thrips, green peach aphid, volatile components, natural insecticide. RESUMOO tripes, Frankliniella schultzei, e o pulgão-verde, Myzus persicae, além de causarem danos diretos a plantas de importância econômica, também são importantes transmissores de fitoviroses, acarretando grandes perdas econômicas. Os constituintes químicos dos óleos essenciais têm sido cada vez mais estudados, pois apresentam uma ampla gama de atividades biológicas. Neste trabalho, objetivou-se avaliar a atividade inseticida do óleo essencial de capim-citronela, Cymbopogon winterianus, sobre F. schultzei e M. persicae. O óleo essencial foi obtido por hidrodestilação e a identificação dos seus componentes foi realizada por CG/DIC e CG/EM. Uma torre de Potter foi utilizada para pulverizar os insetos com óleo essencial. Os componentes majoritários encontrados são geraniol (28,62%), citronelal (23,62%) e citronelol (17,10% ) é mais tóxico para M. persicae do que para F. schultzei. Este óleo essencial mostra-se promissor para o desenvolvimento de inseticidas para o manejo de M. persicae. Termos para indexação:Cymbopogon winterianus, tripes, pulgão-verde, componentes voláteis, inseticida natural.

Molecular markers (RAPD, AFLP and microsatellites) were used to generate a linkage map and to identify QTLs associated to witches' broom (Crinipellis perniciosa) resistance in cacao (Theobroma cacao), using 82 individuals of an F 2 population derived from the clones ICS-1 (susceptible) and Scavina-6 (resistant). Fifteen evaluations of the number of brooms have been carried out in six years (1997)(1998)(1999)(2000)(2001)(2002). In order to increase the precision and accuracy in the measures of resistance, each F 2 plant was cloned in three replications in a randomized block design with singletree plots and evaluated over 2 years. Three hundred and forty-two markers were obtained, being 33 microsatellites, 77 AFLPs and 232 RAPDs. The distribution of the number of brooms in the F 2 population was skewed to resistance, suggesting the involvement of major genes controlling resistance and the repeatability estimated for resistance was 44%. A strong putative QTL was detected as being related to witches' broom resistance. Associated to this QTL, the microsatellite mTcCIR35 explained 35.5% of the phenotypic variation in resistance. This marker is being used for marker-assisted selection in Scavina-6 progenies, including those selected in private plantations, as an auxiliary tool to the phenotypic selection.

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Fatores ambientais contribuem para a produção de sementes de soja com características diferentes do padrão da variedade e a análise visual para determinação de pureza varietal não é suficiente. Marcadores moleculares de DNA podem auxiliar na identificação da pureza genética de sementes, durante o processo de certificação de sementes, uma vez que não sofrem influências ambientais. O objetivo deste trabalho foi avaliar um método de análise da pureza genética de sementes de soja, utilizando marcadores microssatélites. Amostras de DNA de sementes de soja, consideradas atípicas pelo método visual, foram analisadas com microssatélites e comparadas ao padrão da variedade. As amostras de DNA foram analisadas em bulk, o que permitiu diminuir os custos, com a mesma precisão da análise individual. De onze lotes de sementes avaliados como impuros na análise visual, e portanto, eliminados do processo de certificação, apenas quatro apresentaram número de sementes de outras cultivares acima do limite tolerado.

The synthesis of a series of 1,2,3-triazoles using glycerol as starting material is described. The key step in the preparation of these triazolic derivatives is the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC), also known as click reaction, between 4-(azidomethyl)-2,2-dimethyl-1,3-dioxolane (3) and different terminal alkynes. The eight prepared derivatives were evaluated with regard to their fungicide, phytotoxic and cytotoxic activities. The fungicidal activity was assessed in vitro against Colletotrichum gloeosporioides, the causative agent of papaya anthracnose. It was found that the compounds 1-(1-((2,2-dimethyl-1,3-dioxolan-4-yl)methyl)-1H-1,2,3-triazol-4-yl)-cyclo-hexanol (4g) and 2-(1-((2,2-dimethyl-1,3-dioxolan-4-yl)methyl)-1H-1,2,3-triazol-4-yl)propan-2-ol (4h) demonstrated high efficiency in controlling C. gloeosporioides when compared to the commercial fungicide tebuconazole. The triazoles did not present any phytotoxic effect when evaluated against Lactuca sativa. However, five derivatives were mitodepressive, inducing cell death detected by the presence of condensed nuclei and acted as aneugenic agents in the cell cycle of L. sativa. It is believed that glycerol derivatives bearing 1,2,3-triazole functionalities may represent a promising scaffold to be explored for the development of new agents to control C. gloeosporioides.