The Genetic Diversity Of Cacao And Its Utilization

The cacao (Theobroma cacao) plant is an important Neo-Tropical species whose natural habitat is the Amazon basin. Over the last 30 years there has been a considerable geographical expansion in the availability of cacao genetic resources. As a result the plant has a rich genetic diversity that exists at two levels: that of the primitive populations in the area of original distribution of the species, and that of the derived cultivated populations. This book provides a comprehensive review of our current knowledge of the diversity of the species. It starts by examining the diversity and inheritance of the characteristics of primitive populations in the Amazonian and Caribbean regions. It then looks at the evolution of diversity within cultivated populations first in South America and around the Caribbean, and then beyond the Americas. The book describes the inter-relationships between populations based on morphological and molecular markers. It also examines the conservation of genetic resources and how these genetic resources can be utilized to produce new cultivars.

The Background to the Subject: Concepts and a Brieí History; The Terminology Specific to Cacao; The Indicators oí Variability; The Manifestation oí the Diversity and its Conservation; The Foundations oí the Diversity; The Amazonian Region; The Circum-Caribbean Region; The Cultivated Populations as Secondary Depositories oí the Diversity; South America - Populations Derived from an Amazonian Region Germplasm Base; The Circum-Caribbean Region and Neighbouring Territories - Populations that Evolved from a Criollo Germplasm Base; Cacao Beyond the Americas - the Export oí Diversity to the Old World; The Genetics oí the Diversity; The Relationships among Populations; The Utilization of the Genetic Resources.

The tropical cacao tree, Theobroma cacao L., is cultivated to produce seeds, the unique raw material for the chocolate industry. Thus, conservation and use of cacao genetic resources in breeding programs are vital for the cacao-chocolate global economy. Wild cacao populations have a wide geographic distribution in their native range along the Amazon basin, but northwestern Amazonia is the hotspot of cacao genetic diversity. From the rich diversity of cacao (at least twelve genetic clusters are identified) the domestication of cacao in South America led to the development of Criollo, whose s...

Genetic diversity is of fundamental importance in the continuity of a species as it provides the necessary adaptation to the prevailing biotic and abiotic environmental conditions, and enables change in the genetic composition to cope with changes in the environment. Genetic Diversity in Plants presents chapters revealing the magnitude of genetic variation existing in plant populations. The increasing availability of PCR-based molecular markers allows the detailed analyses and evaluation of genetic diversity in plants and also, the detection of genes influencing economically important traits. The purpose of the book is to provide a glimpse into the dynamic process of genetic variation by presenting the thoughts of scientists who are engaged in the generation of new ideas and techniques employed for the assessment of genetic diversity, often from very different perspectives. The book should prove useful to students, researchers, and experts in the area of conservation biology, genetic diversity, and molecular biology.

This book reviews the current state of knowledge concerning cacao pathogens and methods for their management. Topics discussed include the history, biology and genetic diversity of Moniliophthora species (which cause witches’ broom and frosty pod rot) and Phytophthora species (which cause black pod rot) that cause diseases resulting in major losses to cacao production. Emerging pathogens such as Cacao swollen shoot virus and Ceratobasidium theobromae (which causes vascular streak dieback) are also discussed in detail, along with many pathogens of significant local concern. Most of these pathogens represent major risks to global cacao production should they expand into new areas, breaking out of their current limited distributions. By considering cacao diseases as a group, similarities in the available tools and techniques used in their management become apparent, as do their limitations. Gaps in our current knowledge of cacao pathogens and the management of the diseases they cause are detailed, and suggestions for future research directions are provided. This insight allows readers to consider cacao disease threats from a more comprehensive, global perspective and paves the way for an improved synergy of efforts between the various research programs, agencies, and industries, both private and public, with vested interests in cacao production, and cacao farmers.

Cash crops are grown and sold for monetary gain and not necessarily for sustenance. They include coffee, tea, coconut, cotton, jute, groundnut, castor, linseed, cocoa, rubber, cassava, soybean, sweet potato, potato, wheat, corn and teff. While some of these crops have been improved for realizing yield potential, breeding of many of them is still in infancy. Crops that underwent rigorous breeding have eventually lost much of the diversity due to extensive cultivation with a few improved varieties and the diversity in less bred species is to be conserved. Over the past years, scholars and policy makers have become increasingly aware of the short and long-run impact of climatic factors on economic, food security, social and political outcomes . Genetic diversity, natural and induced, is much needed for the future generations to sustain food production with more climate resilient crops. In contrast, crop uniformity produced across the farm fields in the form of improved varieties is genetically vulnerable to biotic and abiotic stresses. Thus, it is essential and challenging to address the issue of compromising between maximizing crop yield under a given set of conditions and minimizing the risk of crop failure when conditions change. Cash crops are grown in an array of climatic conditions. Many of the world’s poor still live in rural areas. Many are subsistence farmers, operating very small farms using very little agricultural inputs for achieving marketable outputs. Conserving the diversity of these crops and addressing all issues of crop culture through modern tools of biotechnology and genomics is a real challenge. We believe the focus of this book is to fill an unmet need of this and other grower communities by providing the necessary knowledge, albeit indirectly via the academics, to manage the risks of cash crops breeding through managing genetic diversity.

Following on from their previous volume on Chocolate as Medicine, Philip K. Wilson and W. Jeffrey Hurst edit this companion volume, Chocolate and Health, providing a comprehensive overview of the chemistry, nutrition and bioavailability of cacao and chocolate. The book begins with a brief historical introduction to the topic, outlining the current and historical medical uses of chocolate and chocolate derivatives. The remainder of the text is arranged into three sections, taking the reader through various aspects of the nutritional and health aspects of cacoa. The first section covers the cultivation, chemistry and genome analysis of cacao. The second section discusses the biochemistry and nutritional components of cacao in relation to health, covering bioavailabilty and the metabolism and metabolomics of cacao. The final section provides an overview of the potential use of chocolate in health and medical care. Each section is written and prepared by experts within each field, providing a global perspective of the current and ongoing research in this area. This text provides the reader with a complete overview of the field and is of interest to food and biomedical scientists, as well as nutritionists, medicinal chemists and anyone with an interest in chocolate.

Agroforestry (AF) is a dynamic, ecologically based, natural resources management system that, by integrating trees on farms, ranches, and in other landscapes, diversifies and increases production and promotes social, economic, and environmental benefits for land users. Further, it is receiving increasing attention as a sustainable land-management option worldwide because of its ecological, economic, and social attributes. Advances have been achieved by building on past research accomplishments and expanding AF’s stakeholder base, which now includes private/public partnerships, communities, ecologists, farmers, indigenous peoples, and policymakers in both temperate and tropical countries. AF has now been recognized as a valuable problem-solving approach to ensuring food security and rebuilding resilient rural environments. Recent studies have shown that more than 1 billion hectares of agricultural land have more than 10% tree cover. Of this area, 160 million hectares have more than 50% tree cover. Agricultural ecosystems can be further improved through AF to achieve environmental restoration, greater farm productivity, and key ecological services, including climate change mitigation and adaptation for improved rural livelihood. In fact, it is largely considered synonymous with climate smart agriculture and a remedy for many modern environmental challenges. Consequently, AF’s knowledge base is being expanded at a rapid rate, as illustrated by the increasing number and quality of scientific publications on various forms and different aspects of AF. This book offers state-of-the-art information on the fundamental concepts and history of AF and its evolution as a science, presenting a wealth of advanced research results and evaluations relating to different aspects of AF. Accordingly, it will be useful for a broad readership, including students, foresters, farmers, local communities, indigenous peoples, civil society institutions, media, policymakers and the general public.