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United States Department of Agriculture

Agricultural Research Service

Research Project: Develop Sustainable Production System for Tropical Tree Crops and Assess Germplasm to Improve Cacao Sustainability

Location: Sustainable Perennial Crops

2013 Annual Report


1a.Objectives (from AD-416):
1. Assess cacao genotypes tolerant to abiotic stresses, evaluate the effects of legume cover crops on cacao yields, and develop improved management systems that maintain or improve cacao yields and environmental conditions.

2. Select, establish, and evaluate Peruvian cacao germplasm accessions for improved agronomic traits.

An amendment to this agreement was implemented in 2012 to address additional critical needs of the Cooperator with regard to collecting specific data. The laboratory lacks equipment to conduct soil quality determinations and is in need of desiccators (n=4), fraction collectors (n=2), microscope (n=1), and HOBO data loggers (n=6) for monitoring climatic data in cacao genotypes assessment for abiotic stress studies. SPCL will send these items to the Cooperator for the duration of this agreement and the subsequent agreement. Due to the projected use that these items will receive during this project, their value at that time, and the cost to return, it is in the best interest of ARS that the title of these items be vested with the Cooperator at the end of the subsequent agreement.


1b.Approach (from AD-416):
1. Establish controlled and field studies to evaluate native and international cacao clones tolerance to abiotic stresses (drought, light, soil acidity), develop improved field management systems in selected areas of Peru to evaluate their impact on soil quality parameters and yield of cacao, and further evaluate the effects of legume cover crops on factors affecting yields of cacao.

2. Assess genetic diversity in wild populations and farmer selections of cacao using molecular markers. A core set of the germplasm then will be selected and evaluated in clonal gardens and farmers’ fields for agronomic traits.


3.Progress Report:

The purpose of this Specific Cooperative agreement is to fund collaborative field research on Sustainable Production Systems for tropical tree crops. Specific research activities include the identification of cacao genotypes with superior abilities to grow under environmental stresses, like drought or acid soils. The research will also evaluate the effects of leguminous cover crops on cacao yields. The program will also characterize and manage soil nutrition and develop improved cacao crop management with the goal of optimizing cacao yields. Finally, the project will establish and evaluate landrace and wild Peruvian Cacao germplasms for production potentials. The collaborative research proposed in this agreement is being conducted with scientists from the Tropical Crop Institute (ICT) in Tarapoto, Peru and the National Agricultural University of La Molina (UNALM) in Lima, Peru.

Early growth performance is being evaluated for wild cacao trees collected from various Amazon River basins, and national and international cacao types established in the clonal cacao garden. International cacao clones from the University of Reading, UK and national and Amazon River basin clones are being multiplied in clonal gardens for abiotic stress assessments, such as drought and shade tolerance. At this location long term field studies have been established to evaluate cacao genotype responses to the Andean (traditional slash and burn system) and agroforestry management (managed canopy system where the forest is thinned and the cacao is planted under the existing trees). In these management systems soil quality parameters are being determined. The growth and development of the selected cacao genotypes under the agroforestry system is better than under the Andean management system. Effectiveness of slow release fertilizer formulation on cacao performance is being evaluated under field conditions and is being compared to conventional fertilizers in these rainforest environments. Cacao yields are higher with the slow release formulation than with conventional fertilizer formulations. In 2012, budwood from wild cacao trees was collected from southern Peru including Urubamba, Cusco and Madre de Dios regions and propagated in the field genebank in Tarapoto, Peru. Samples from all 131 accessions collected from southern Peru were sent to Beltsville, MD and analyzed using SNP markers. This new information allows the identification of new diversity gaps that currently exist on the Napo and Yavari river systems. These studies are looking at the genetic diversity of the wild cacao from Peru so that these can be conserved and utilized to improve Peruvian cacao production. Experiments established at Tarapoto are also serving as a training site for many of the region’s farmers and graduate students, where they are being educated in sustainable cacao production methods.


Last Modified: 10/23/2014
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