Genetic variability of cocoa from the amazon basin: implications for genetic conservation

The cocoa and chocolate production chain involves US$60 billion annually and three million farmers around the world, in an area exceeding nine million hectares. The use of wild germplasm will enable to generate new disease- and pest-resistant cultivars and ability to adapt to changing environments. Here we evaluated 145 cocoa accessions, originated from nine Amazonian basins, based on eight fruit traits. Univariate anova showed significant differences (p<0.05) for all traits. For seven traits, the variance component within basins was higher (81.5%, on average). Therefore, it is recommended that the collection of wild accessions prioritize a larger number of plants from a few populations of the most divergent basins. The multivariate analyses revealed a greater divergence between the Ji-Paraná-RO and Solimões/Amazonas-PA basins (27.69) and a greater similarity between Alien clones-PER and Solimões/Amazonas-AM (0.66) in relation to their populations. They also revealed that the accessions differentiation occurred according to the river basin system. These results allowed elucidate the genetic structure and distribution of cacao populations. In addition, strengthen the importance of collecting and conserving germplasm to preserve genetic resources.

Effect of organic fertilization and pruning on cacao yield in Cundinamarca, Colombia / Efecto de la fertilización orgánica y la poda sobre la producción de cacao en Cundinamarca, Colombia

ABSTRACT Cacao has high social importance in Colombia but requires cultivation techniques that improve its productivity, especially in the production of organic cacao. Pruning and organic fertilizers were assessed as treatments to increase the bean yield in an old cacao crop in Cundinamarca. The positive effects of organic fertilizer application and pruning on the pod morphometry and bean yield were established. The application of organic fertilizers with pruning, in general, increased the length and circumference of cacao pods. A negative correlation (R=-0.618) was found among the relative chlorophyll contents in leaves at the end of the harvest period and with the number of pods per tree. A positive correlation (R=0.748) was obtained between the fresh weight of pods and the dry weight of beans. No correlation was established between the relative chlorophyll contents in leaves and the bean dry weight. Pruning plus organic fertilization increased the total dry weight of beans per tree at almost 15 %, which makes pruning with organic fertilizer application the best tool for increasing yield in organic cacao production in old plantations in Cundinamarca.

RESUMEN El cultivo de cacao tiene una alta importancia social en Colombia, pero requiere la implementación de técnicas de cultivo que mejoren su productividad, principalmente, en la producción de cacao orgánico. La poda y los fertilizantes orgánicos fueron evaluados, como los tratamientos para incrementar el rendimiento de cacao, en una plantación antigua en el departamento Cundinamarca. La aplicación de fertilizantes orgánicos y la poda tuvieron efectos positivos sobre la morfometría del fruto y el rendimiento del cacao. La aplicación de fertilizantes orgánicos con poda, en general, aumentó la longitud y el diámetro de frutos de cacao. Se encontró una correlación negativa (R=-0,618) entre el contenido relativo de clorofila en hojas al final del período de cosecha y el número de frutos por árbol. Se obtuvo una correlación positiva (R=0,748) entre el peso fresco de frutos y el peso seco de semillas. No se estableció correlación entre el contenido relativo de clorofila en hojas y el peso seco de semillas. La poda más fertilización orgánica aumentó el peso seco total de semillas por árbol, en casi un 15 %, lo que convierte la poda con aplicación de fertilizante orgánicos en una herramienta para aumentar el rendimiento de cacao orgánico en antiguas plantaciones, en el departamento Cundinamarca.

Proximal chemical evaluation, antioxidant content and fatty acids in fermented and dried cocoa beans, roasted cocoa beans and cocoa pulp bar (Theobroma cacao L. Criollo cultivar)

ABSTRACT The objective of this work was to evaluate the proximal chemical composition, antioxidant activity assays with total phenol, 2,2-Diphenyl-1-Picrylhydrazyl, 2'2-azino-bis(3-ethylbenzothiazolin-6-sulfonic acid) diammonium salt, iron reducing antioxidant power, and the fatty acid composition of fermented and dried cocoa beans, roasted cocoa beans and cocoa pulp bar. The fermented and dried cocoa beans were purchased, roasted (115 °C for 5 min) and homogenized. The mixture was brought to its melting point (58 °C for 5 min). In the cocoa pulp bar there was an increase in lipids (53.0%). The roasted affected the concentration of ashes (3.38-2.98%). Total phenol (1.8, 1.5 and 1.3 mg AEG kg-1), 2,2-Diphenyl-1-Picrylhydrazyl (65.8, 64.4 and 65.0 μmol ET kg-1), 2'2-azino-bis(3-ethylbenzothiazolin-6-sulfonic acid) diammonium salt (3.60, 3.00 and 2.30 μmol EAC kg-1) and iron reducing antioxidant power (0.09, 0.07 and 0.06 mg Fe2+ kg-1) presented significant differences (p<0.05) in the fermented and dried cocoa beans, roasted cocoa beans and cocoa pulp bar respectively, however, the changes were minimal. The cocoa pulp bar had a higher concentration of unsaturated fatty acid (89.2%), where oleic (48.6%) was predominated. Therefore, the cocoa pulp bar is a food with an important antioxidant content, moreover, it has a higher concentration of unsaturated fatty acid, which is desirable in the diet.

RESUMEN El objetivo de este trabajo fue evaluar la composición química proximal, el contenido de antioxidantes con los ensayos de fenoles totales, 2,2-Difenil-1-Picrilhidrazil, Ácido 2'2-azino-bis (3-etilbenzotiazolin-6-sulfónico), sal de diamonio y poder antioxidante reductor del hierro, y la composición de ácidos grasos en los granos de cacao fermentados y secos, granos de cacao tostados y barra de pulpa de cacao. Se compraron los granos de cacao fermentado y seco y se tostaron (115 °C durante 5 min), y se homogeneizaron. La mezcla se llevó a su punto de fusión (58 °C durante 5 min). En la barra de pulpa de cacao hubo un aumento de lípidos (53,0%). El tostado afectó la concentración de cenizas (3,38 - 2,98%). En los resultados de fenoles totales (1,80, 1,50 y 1,30 mg AEG kg-1), 2,2-Difenil-1-Picrilhidrazil (65,8, 64,4 y 65,0 μmol ET kg-1), Ácido 2'2-azino-bis (3-etilbenzotiazolin-6-sulfónico), sal de diamonio (3,6, 3,0 y 2,3 μmol EAC kg-1) y poder antioxidante reductor del hierro (0.09, 0.07 y 0.06 mg Fe2+ kg-1) presentaron diferencias significativas (p<0.05) en los granos de cacao fermentados y secos, granos de cacao tostados y barra de pulpa de cacao respectivamente, sin embargo, los cambios fueron mínimos. La barra de pulpa de cacao presentó una mayor concentración de ácidos grasos insaturados (89%), donde predominó el oleico (48,6%). Por lo tanto, la barra de pulpa de cacao es un alimento con importante contenido en antioxidantes, además, tiene una mayor concentración de ácidos grasos insaturados, lo que es deseable en la dieta.

Heavy metals content in soils and cocoa tissues in Magdalena department Colombia: emphasis in cadmium / Contenido de metales pesados en suelos y tejidos de cacao en el departamento del Magdalena, Colombia: énfasis en cadmio / Teor de metais pesados em solos e tecidos de cacau no departamento de Magdalena, Colômbia: ênfase no cádmio

ABSTRACT Cocoa (Theobroma cacao L.) is a species originating from the humid tropics. Over 70,000 km2 worldwide is dedicated to growing cocoa, and approximately 30% of its global production is concentrated in the equatorial regions of Central and South America, the Antilles and tropical Asia. The demand for cocoa is growing significantly but the presence of cadmium (Cd) in the species is a potential problem limiting its commercialization. The present study determined the Cd, Ni, Pb and Cr content in two cocoa-producing regions in northern Colombia. Foliage (leaf, bean and shell) and soil were analyzed. The mean Ni, Pb and Cr content in the plant tissue did not exceed the maximum permissible limits set by the United States Environmental Protection Agency (EPA). The mean Cd content in the beans was 0.51 mg kg-1 in region 1 and 0.66 mg kg-1 in region 2, which are considered risky per reports from the European Union and restrict the product's export. These results serve as a reference for future research on cocoa.

RESUMEN El cacao (Theobroma cacao L.) es una especie originaria de los trópicos húmedos. Más de 70,000 km2 en todo el mundo están dedicados a su cultivo y aproximadamente el 30% de su producción mundial se concentra en las regiones ecuatoriales de América Central y del Sur las Antillas y Asia tropical. La demanda de cacao está creciendo significativamente, pero la presencia de cadmio (Cd) en la especie es un problema potencial que limita su comercialización. El presente estudio determinó el contenido de Cd, Ni, Pb y Cr en dos regiones productoras de cacao en el norte de Colombia. Se analizaron el tejido (hoja, frijol y cáscara) y el suelo. El contenido medio de Ni, Pb y Cr en el tejido vegetal no excedió los límites máximos permisibles establecidos por la Agencia de Protección Ambiental (EPA) de los Estados Unidos. El contenido medio de Cd en los frijoles fue de 0,51 mg kg-1 en la región 1 y 0,66 mg kg-1 en la región 2, que se consideran riesgosos según los informes de la Unión Europea y restringen la exportación del producto. Estos resultados sirven como referencia para futuras investigaciones sobre el cacao.

RESUMO O cacau (Theobroma cacao L) é uma espécie originária dos trópicos úmidos. Mais de 70.000 km2 em todo o mundo são dedicados à sua cultura e aproximadamente 30% de sua produção global está concentrada nas regiões equatoriais da América Central e do Sul, Antilhas e Ásia tropical. A demanda por cacau está crescendo significativamente, mais a presença de cádmio (Cd) nas espécies é um problema potencial que limita sua comercialização. O presente estudo determinou o teor de Cd, Ni, Pb e Cr em duas regiões produtoras de cacau no norte da Colômbia. A folhagem (folha, feijão e casca) e o solo foram analisados. O teor médio de Ni, Pb e Cr no tecido vegetal não excedeu os límites máximos permitidos estabelecidos pela Agência de Proteção Ambiental dos Estados Unidos (EPA). O conteúdo médio de Cd nos grãos foi de 0,51 mg kg-1 na região 1 e 0,66 mg kg-1 na região 2, que são considerados de risco por relatórios da União Europeia e restringem a exportação do produto. Esses resultados servem como referência para futuras pesquisas sobre cacau.

Soil patterns and foliar standards for two cocoa clones in the States of Espírito Santo and Bahia, Brazil / Padrões de solo e normas foliares para dois clones de cacau cultivados nos Estados do Espírito Santo e Bahia, Brasil

ABSTRACT: The objective of this research was to establish soil patterns and foliar standards for clonal crops of cocoa CCN51 and PS1319 in the Atlantic regions within the northern Espírito Santo and southern Bahia States. Samples were collected from September to October 2015, in 45 high productive plots, being 23 plots of clone CCN51 and 22 of clone PS1319. Sufficiency ranges for soil and foliar standards were recommended for cocoa clones CCN51 and PS1319 planted in the Northern Espírito Santo and Southern Bahia states. Differences in the contents of foliar macronutrients K, Ca, Mg, S and micronutrients Fe and Mn, were verified between clones CCN51 and PS1319. Differences reported for standards from different geographical regions confirmed that these standards need to be regional and specific for different cocoa clones.

RESUMO: O objetivo deste trabalho foi estabelecer padrões de solo e padrões foliares para culturas clonais de cacau CCN51 e PS1319 nas regiões do Atlântico no norte do Espírito Santo e no sul da Bahia. As amostras foram coletadas de setembro a outubro de 2015, em 45 parcelas de alta produtividade, sendo 23 parcelas do clone CCN51 e 22 do clone PS1319. As faixas de suficiência para solo e padrões foliares foram sugeridas para os clones de cacau CCN51 e PS1319 plantados no norte do Espírito Santo e no sul da Bahia. Diferenças nos teores dos macronutrientes foliares K, Ca, Mg, S e micronutrientes Fe e Mn foram verificadas entre os clones CCN51 e PS1319. As diferenças relatadas para padrões de diferentes regiões geográficas permitem confirmar que esses padrões precisam ser regionais e específicos para diferentes clones de cacau.

Cascarilla de cacao venezolano como materia prima de infusiones / Husk of Venezuelan cocoa as raw material of infusions

En la industria del cacao se subutilizan materiales que pudieran ser ingredientes en la elaboración de productos novedosos, uno de ellos es la cascarilla de cacao. Estudios previos le atribuyen a dicho material una alta capacidad antioxidante, lo que sumado a su relativo bajo costo, lo hacen un atractivo ingrediente para la elaboración de infusiones, pero antes de promoverlo como tal, se necesita garantizar su calidad. En este estudio se evaluó la composición química, la calidad microbiológica de la cascarilla de cacao, así como también aquellos parámetros que determinan su uso como materia prima en la preparación de infusiones. Las semillas de cacao fueron cultivadas en dos estados en Venezuela. A la cascarilla de cacao se le determinó el contenido de humedad, proteínas, grasa, cenizas, carbohidratos, minerales, calidad microbiológica, ocratoxina A y las propiedades como antioxidante, contenido de materias extrañas, cenizas insolubles en HCL y extracto acuoso. Los métodos aplicados se basan en normas nacionales e internacionales. Se determinaron diferencias significativas entre las muestras mediante la aplicación de ANOVA. Un bajo contenido de humedad pero alto en cenizas, una calidad microbiológica ajustada a la norma y la ausencia de ocratoxina A se observaron en la totalidad de las muestras analizadas. El bajo contenido de materias extrañas y alto valor del extracto acuoso y alto contenido de polifenoles con actividad antioxidante permite recomendar la cascarilla del cacao como materia prima para preparar infusiones.

In the cocoa bean industry, some by-products go underutilized. Some of these components could provide other innovative products, and such is the case with the husk of the cocoa bean. Previous studies have attributed the husk with a high antioxidant capacity, which added to its relative low cost, makes it an attractive ingredient for the production of infusions. However, prior to promoting it as such, its quality needs to be guaranteed. This study evaluated the chemical composition of the husk of cocoa, its microbiologic quality and other parameters in order to be considered raw material in the preparation of infusions. The cocoa was cultivated in two different states in Venezuela. Moisture, protein, fat, ash, carbohydrates, microbiologic quality and ochratoxin A as well antioxidant properties, content of foreign matter, insoluble ash in HCL and aqueous extract were evaluated in the husk of cocoa seeds. Applied methods were in compliance with national and international norms. Significant differences were determined between the samples through the ANOVA application. A low level in moisture content, but high in ash, along with a microbiologic quality that met the norm, and an absence of ochratoxin A were observed in the totality of the analyzed samples. Low levels of foreign matter, the high value of its aqueous extract and high phenolic compounds content with antioxidant activity allow for the recommendation of the husk of cocoa as raw material for the preparation of infusions.

Fotossíntese, crescimento e incidência de insetos-praga em genótipos de cacau pulverizados com silício / Photosynthesis, growth and incidence of insect pest in cacao genotypes sprayed with silicon

Poucos são os estudos envolvendo o efeito do silício sobre a fisiologia e a resistência do cacaueiro a insetos-praga. Com o objetivo de avaliar as alterações fisiológicas, a incidência e o nível de dano provocado por insetospraga após aplicação de silicato de potássio em genótipos de cacau, foi conduzido em campo, um experimento no delineamento de blocos casualizados, em esquema fatorial 3 x 3 com 4 repetições, sendo 3 genótipos de cacau (TSH 1188, CCN 51 e Catongo) e 3 doses de silicato de potássio (0; 3 e 6 mL L-1). Avaliou-se o crescimento, a cinética da emissão da fluorescência da clorofila, o teor de Si, o índice de clorofila, além da incidência e nível de dano provocado por insetospraga. A aplicação de silicato de potássio na dose 6 mL L-1 reduziu a maioria das variáveis de crescimento. O TSH 1188 foi o único genótipo que apresentou incremento no índice de clorofila e no desempenho das variáveis de fluorescência com a aplicação de 3 mL L-1. A aplicação de silicato de potássio não influenciou o teor foliar de Si nos genótipos estudados, mas reduziu a incidência e o nível de dano provocado por insetos-praga.

There are few studies of the effect of silicon on the physiology and resistance to insect pests in cocoa. With aim to evaluate the physiological changes, the incidence and level of damage caused by insect pests after application of potassium silicate in cacao genotypes was conducted in the field, an experiment in randomized blocks in factorial scheme 3 x 3 with four replications, with three genotypes of cocoa (TSH 1188, CCN 51 and Catongo) and three doses of potassium silicate (0, 3 and 6 mL L-1). We evaluated the growth kinetics of chlorophyll fluorescence emission, the Si content, chlorophyll content, and the incidence and level of damage by insect pests. The application of potassium silicate at a dose 6 mL L-1 reduced the majority of growth variables. The TSH 1188 was the only genotype that showed increase in chlorophyll content and in performance of variable fluorescence with the application of 3 mL L-1. The application of potassium silicate did not influence the content of Si in leaf genotypes, but reduced the incidence and level of damage by insect pests.

Análise comparativa de métodos de determinação de área foliar em genótipos de cacau / Comparative analysis of methods of determining leaf area in cocoa genotypes

O conhecimento da área foliar é uma ferramenta importante na análise do crescimento e desenvolvimento vegetal. Desse modo, objetivou-se comparar os métodos, integrador de área foliar, software DDA, software ImageJ e de medição das dimensões foliares, visando definir o fator de correção mais adequado para estimar a área foliar de genótipos cacau. O experimento foi desenvolvido na Estação Experimental Filogônio Peixoto no delineamento de blocos casualizados com quatro repetições em arranjo fatorial 4 x 8, sendo 4 métodos de avaliação de área foliar e oito genótipos de cacau (Variedade Comum; TSH 1188; Catongo; CCN 51; ICS 1; ESFIP 02; SJ 02 e PH 16). Os resultados foram submetidos a análises de variância e correlação e as médias comparadas pelo teste Tukey 5%. Não houve diferença entre os métodos de determinação de área foliar, sendo constatada correlação positiva entre os métodos DDA, ImageJ e Dimensões foliares com o método do integrador de área foliar (padrão), com valores dos coeficientes de correlação (r) superiores a 0,98. Os genótipos TSH 1188, Catongo e CCN 51 apresentaram maior área foliar média. Os métodos testados mostraram-se viáveis para estimar área foliar do cacaueiro com precisão, contudo, foram encontrados três grupos de fatores de correção, sendo K = 0,682 para os genótipos SJ 02 e Variedade Comum, K = 0,670 para os genótipos CCN 51, Catongo, TSH 1188 e ICS 01 e K = 0, 655 para os genótipos ESFIP 02 e PH 16.

The knowledge of the leaf area is an important tool in the analysis of plant growth and development. Thus, the objective was to compare the methods, integrating leaf area, software DDA, software ImageJ and measurement of leaf dimensions, aiming to define the most appropriate correction factor to estimate the leaf area of cacao genotypes. The experiment was conducted at the Experimental Station Filogônio Peixoto in a randomized block design with four replications in a factorial arrangement of 4 x 8, being 4 assessment methods of leaf area and eight cacao genotypes (Common Variety; TSH 1188; Catongo; CCN 51; ICS 1; ESFIP 02; SJ 02 e PH 16). The results were submitted to analysis of variance and correlation and means were compared by Tukey test 5%. There was no difference between the methods of determining leaf area, being found positive correlation between the methods DDA, ImageJ and leaf dimensions with the integrative method of leaf area (default), with values of correlation coefficients (r) greater than 0,98. The genotypes TSH 1188, Catongo and CCN 51 have higher average leaf area. The methods tested were shown to be viable to estimate leaf area of cacao accurately, however, we found three groups of correction factors, being K = 0,682 for genotypes SJ 02 and Common Variety, K = 0,670 for genotypes CCN 51, Catongo, TSH 1188 and ICS 01 and K = 0, 655 for genotypes ESFIP 02 and PH 16.

Actividad antioxidante de clones de cacao (Theobroma cacao l. ) finos y aromáticos cultivados en el estado de Chiapas, México / Antioxidant activity of clones of cocoa (Theobroma cacao L.) fine and aromatic grown in the state of Chiapas-México

Objetivo: determinar la capacidad antioxidante y contenido de grasa de clones de cacao, provenientes de especies nativas del Estado de Chiapas, México. Materiales y métodos: en extractos de 34 muestras semillas de cacao diluidas en metanol al 95% y clasificadas según pH en tres grupos: I (5,52-5,90), II (5,91- 6,28) y III (6,29-6,67), se realizaron ensayos analíticos de variables físicas y químicas. Se evaluó la inhibición de radicales 2,2-difenil-2-picrilhidrazil (DPPH) a 517 nm, el contenido de polifenoles mediante el reactivo de folin-ciocalteu (FCR) a 765 nm y cantidad de grasas totales según método AOAC. Se aplicó un ANOVA al nivel del 95%, con post prueba Tukey para comparar de medias muestrales y determinar diferencias significativas (p<0.05), además de sus correlaciones lineales. Resultados: El Grupo I con menor pH, mostró menor contenido calórico (26,3±3,6% de grasas), posee la mejor actividad antioxidante con menor valor EC50 de 4182 ppm y mayor contenido de polifenoles 6,6±0,32 equivalentes de ácido gálico por 100 g de muestra seca. Conclusión: El cacao chiapaneco posee importantes ventajas competitivas en el mercado, por su calidad como alimento funcional-nutracéutico y como materia prima para la industria alimentaria, fuente de antioxidantes y aditivos naturales, con potencial consumo en la industria farmacéutica y cosmética internacional.

Objective: To determine antioxidant capacity and fat content of cacao clones from the State of Chiapas, Mexico. Materials and Methods: 34 cocoa beans samples were diluted in 95% methanol and classified by pH in: group I (5.52-5.90), group II (5.91- 6.28), and group III (6.29-6.67). Chemical and physical analysis were developed. 2,2- diphenyl-2-picrylhydrazyl (DPPH) inhibition was evaluated at 517 nm. Polyphenol and fat contents were evaluated by Folin-Ciocalteu Reagent at 765 nm and AOAC method, respectively. Differences in variables were evaluated by ANOVA and Tukey test, in addition to its linear correlations. Results: Group I showed the lowest caloric content (26.3±3.6% fat), the best antioxidant activity with lower EC50 value of 4182 ppm and the highest polyphenol content (6.6±0.3 gallic acid/100 g dry sample). Conclusion: Chiapas cocoa has significant competitive advantages due to its quality as a functional and nutraceutical food. It is a good raw material for food industry because it is a good source of antioxidants and natural additives. Furthermore, it is a potential ingredient in the international pharmaceutical and cosmetic industry.

CARACTERIZACIÓN MOLECULAR DE CLONES DE Theobroma cacao L, POR MEDIO DE MARCADORES MOLECULARES MICROSATÉLITES / Theobroma cacao L. CLONES MOLECULAR CHARACTERIZATION USING MOLECULAR MICROSATELLITE MARKERS

Theobroma cacao L. es la única especie del género Theobroma que se explota comercialmente en grandes extensiones, registrando en la actualidad una amplia distribución mundial, a través de programas de desarrollo directamente influenciados por factores vinculados al mercado y por los intereses de productores, comerciantes, industriales y consumidores. En este estudio se evaluaron 12 clones de cacao por medio de marcadores moleculares utilizando 10 secuencias microsatélites (SSRs), como un estudio piloto antes de un ensayo a mayor escala. Los datos se procesaron mediante el programa Power Marker Versión 3.25. Se estimaron las frecuencias alélicas y luego se generó una matriz de distancias genéticas basada en el coeficiente de Nei. Utilizando el algoritmo de agrupamiento UPGMA se generó el dendrograma correspondiente. El análisis de diversidad mostró un índice de diversidad genética total de 0,6944 considerado intermedio para los materiales evaluados. La estimación de la heterocigosidad promedio fue de 0,58579 y de promedio del contenido de información polimórfica de 0,6523. En este estudio los marcadores mTcCIR6, mTcCIR25, mTcCIR26 y mTcCIR12 son los más informativos y polimórficos. Se recomienda relacionar los resultados de diversidad genética con caracteres morfo-agronómicos y de patogenicidad en los distintos clones de cacao a fin de consolidar estrategias eficaces de mejoramiento y control de enfermedades.

Theobroma cacao L. is the only Theobroma species that is commercially exploited in enormous extensions, registering presently wide distribution worldwide through development programs directly influenced by factors linked to the market and the producers, traders, industrials, and consumers’ interests. In this study 12 cacao clones were evaluated by means of molecular markers using 10 microsatellite sequences (SSRs) as a pilot study before a test at a greater scale. The data were processed using the Power Maker Version 3.25 program. The allelic frequencies were stimated and a genetic distance matrix was developed based on the Nei coefficient. Using the UPGMA grouping algorithm the corresponding dendrogram was generated. The diversity analysis showed a total genetic diversity index of 0.6944 considered intermediate for the materials evaluated. The average heterozygocity estimate was 0.58579 and the average polymorphic information content was 0.6523. In this study markers mTcCIR6, mTcCIR25, mTcCIR26 and mTcCIR12 are the most informative and polymorphic ones. It is recommended to relate the genetic diversity results with morpho-agronomic and pathogenicity characters in the different cacao clones in order to consolidate efficient strategies for disease improvement and control.

Cacao yield in different planting densities

The effect of six planting densities on cacao yield of a commercial hybrid mixture as well as the interaction of planting densities with the years were investigated. Crop data collected over a 14-year period (1977-1990) showed that it was possible to optimise the regional cacao yields by implementing high planting densities (2500 and 1736 trees ha-1). This was however only true for the first half of the crop period. In the second half, low planting density (1059 trees ha-1) attained the best yields. This change in the ranking of planting densities over the years confirmed the presence of density-year interaction. Alternatives to achieve high productivity in high planting density systems were presented and discussed.

O efeito de seis densidades de plantio sobre a produção de um híbrido comercial de cacau, bem como a interação das densidades com os anos, foi investigado. Dados coletados do cultivo por 14 anos (1977-1990) mostraram que é possível otimizar a produção de cacau da região implementando uma alta densidade populacional (2500 e 1736 plantas ha-1). Todavia, isto se verificou apenas para a primeira metade do período de cultivo. Na segunda metade, a baixa densidade (1059 plantas ha-1) foi superior em produção. Esta mudança na densidade com o passar dos anos foi confirmada pela presença da interação densidades por anos. Alternativas para alcançar elevadas produtividades nos sistemas com altas densidades foram apresentadas e discutidas.