Population Structure of in the Main Cacao Producing Departments of Colombia.

The witches' broom () is considered as one of the main threats for cacao production and, consequently, for chocolate production worldwide. In this work, the genetic diversity and population structure of were analyzed for 59 isolates collected in five departments of Colombia and using 10 microsatellite markers. Analyses revealed 35 multilocus genotypes and clonal populations structure according to linkage disequilibrium analysis.

Spatial and Temporal Analysis of Epidemic in Newly Established Cacao Plantations.

Studying spatial and temporal plant disease dynamics helps us to understand pathogen dispersal processes and improve disease control recommendations. In this study, three cacao plots devoid of primary inoculum of (causal agent of cacao black pod rot disease) upon establishment in 2006 were monitored for presence of disease on a weekly basis from 2009 to 2016. Ripley's () function, join count statistics, and Fisher's Exact test were used to analyze spatial and temporal disease dynamics.

Genetic and environmental links between traits of cocoa beans and pods clarify the phenotyping processes to be implemented.

The average weight of cocoa beans is not generally taken into account during breeding processes, although it is a trait of interest. Several studies indicate that the weight of the beans has a high heritability in Theobroma cacao. However, the values obtained from different countries for the same clone often vary.

Unraveling the Complexity of Coffee Leaf Rust Behavior and Development in Different Agroecosystems.

Crop health management systems can be designed according to practices that help to reduce crop losses by restricting pathogen development and promoting host plant growth. A good understanding of pathogen and host dynamics, which are interdependent, is therefore needed. In this article, we used a holistic approach to explain the behavior of coffee leaf rust (CLR), a major coffee disease.

Factors Affecting the Dynamics of Frosty Pod Rot in the Main Cocoa Areas of Santander State, Colombia.

Frosty pod rot (FPR) caused by is the primary disease affecting cacao production in the major producing countries of the Americas and is one of the major threats to cacao worldwide. The incidence of FPR on clones with different levels of resistance was investigated in four localities of Santander State, Colombia, between July 2013 and May 2015. Dynamics of diseased pods were modeled using boosted regression trees, a machine learning technique that allows regressions to be performed without prior statistical assumptions.

Geographic Differentiation and Population Genetic Structure of Moniliophthora roreri in the Principal Cocoa Production Areas in Colombia.

Frosty pod rot (FPR) disease on cocoa, caused by Moniliophthora roreri, is one of the most devastating cocoa disease in the Western Hemisphere. In Colombia, the disease is particularly severe in the Magdalena Valley, which is considered the possible center of origin for the pathogen species. We analyzed the genetic diversity of isolates from the departments of Santander, Antioquia, Tolima, and Huila in Colombia using 23 simple-sequence repeats (SSR) markers.

Tree spatial structure, host composition and resource availability influence mirid density or black pod prevalence in cacao agroforests in Cameroon.

Combining crop plants with other plant species in agro-ecosystems is one way to enhance ecological pest and disease regulation mechanisms. Resource availability and microclimatic variation mechanisms affect processes related to pest and pathogen life cycles. These mechanisms are supported both by empirical research and by epidemiological models, yet their relative importance in a real complex agro-ecosystem is still not known.

Pantoea coffeiphila sp. nov., cause of the 'potato taste' of Arabica coffee from the African Great Lakes region.

Six isolates recovered from coffee seeds giving off a potato-like flavour were studied. Gene sequencing (rrs and rpoB) showed they belong to the genus Pantoea. By DNA-DNA hybridization, the isolates constituted a genomic species with less than 17% relatedness to 96 strains representing enterobacterial species.

Shade tree spatial structure and pod production explain frosty pod rot intensity in cacao agroforests, Costa Rica.

Vegetation composition and plant spatial structure affect disease intensity through resource and microclimatic variation effects. The aim of this study was to evaluate the independent effect and relative importance of host composition and plant spatial structure variables in explaining disease intensity at the plot scale. For that purpose, frosty pod rot intensity, a disease caused by Moniliophthora roreri on cacao pods, was monitored in 36 cacao agroforests in Costa Rica in order to assess the vegetation composition and spatial structure variables conducive to the disease.

Geographical differentiation of the molecular diversity of cacao swollen shoot virus in Togo.

The variability of cacao swollen shoot virus (CSSV) was studied in two areas of Togo with distinct epidemiological backgrounds, Kloto and Litimé. This molecular study was based on 120 sequence comparisons of the first part of ORF3 of the viral genome. The phylogenetic study distinguished three groups of CSSV isolates, A, B, and C, with clear geographical differentiation between the Kloto and Litimé areas.

Topography and crop management are key factors for the development of american leaf spot epidemics on coffee in costa rica.

ABSTRACT We monitored the development of American leaf spot of coffee, a disease caused by the gemmiferous fungus Mycena citricolor, in 57 plots in Costa Rica for 1 or 2 years in order to gain a clearer understanding of conditions conducive to the disease and improve its control. During the investigation, characteristics of the coffee trees, crop management, and the environment were recorded. For the analyses, we used partial least-squares regression via the spline functions (PLSS), which is a nonlinear extension to partial least-squares regression (PLS).

Effect of genotype of cocoa (Theobroma cacao) on attractiveness to the mirid Sahlbergella singularis (Hemiptera: Miridae) in the laboratory.

Background: Mirids are a major constraint to cocoa growing in Africa. Cocoa breeding for tolerance/resistance could be effective in an integrated pest management system. Attractiveness is one aspect of tolerance/resistance, and decreasing the attractiveness of cocoa trees should be a good way of reducing damage.

Dissecting apple tree architecture into genetic, ontogenetic and environmental effects: mixed linear modelling of repeated spatial and temporal measures.

The present study aimed to dissect tree architectural plasticity into genetic, ontogenetic and environmental effects over the first 4 yr of growth of an apple (Malus x domestica) F1 progeny by means of mixed linear modelling of repeated data. Traits related to both growth and branching processes were annually assessed on different axes of the trees planted in a staggered-start design. Both spatial repetitions, (i.

Definition of architectural ideotypes for good yield capacity in Coffea canephora.

Background: Yield capacity is a target trait for selection of agronomically desirable lines; it is preferred to simple yields recorded over different harvests. Yield capacity is derived using certain architectural parameters used to measure the components of yield capacity.

Methods: Observation protocols for describing architecture and yield capacity were applied to six clones of coffee trees (Coffea canephora) in a comparative trial.

Characterization of branching in two Hevea brasiliensis clones.

Rubber has been grown for several decades in Africa, notably in Ivory Coast. Although the yields obtained with selected clones are good, some problems with adaptation to edaphic and climatic conditions have yet to be solved. Of these problems, tree breakage due to violent winds during frequent storms is a major handicap.

Estimation of production losses caused by the coffee berry borer (Coleoptera: Scolytidae) and calculation of an economic damage threshold in Togolese coffee plots.

The coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae), which exists in all coffee producing zones, is a major pest. The seriousness of this scolytid was assessed in Togolese plots spread over five agroclimatic zones, by determining the attack rate from a sample of coffee trees. The work was carried out over 2 yr and revealed that weight losses were proportional to the attack rates.

Assessment of the value of doubled haploids as progenitors in cocoa (Theobroma cacao L.) breeding.

In order to evaluate twelve doubled haploids (DHs) of Theobroma cacao L. used as parents, a trial was set up in Côte d'Ivoire. Several traits were observed, such as yield, vigour, yield/vigour ratios, resistance to the black pod disease caused by Phytophthora, percentage of flat beans and mean weight of 100 cocoa beans.