Cassava (Manihot esculenta Crantz) provides a staple food source for millions of people in tropical and subtropical world regions. Brazil is the major center of diversification for species of the Manihot, and a center for domestication of the cultivated species originated from wild ancestral M. esculenta subsp. flabellifolia. Genetic breeding of cassava depends on landraces. Molecular phylogenetic technologies used to study genetic traits selected by mankind in crops, are likely to predict proposed “domestication syndrome.” Phylogenetic trees use DNA sequences alignment to infer on gene historical events. A study on regulatory and structural complexity that dictates gene/protein function, will add non-sequence information to predict a more complete understanding of functional evolution. Transcriptional profile contains critical information on when and where a gene is manifested. These regulatory properties could explain functional genes diversity achieved within gene families across closely related species such as cassava and its ancestor. Microarray technologies measure transcriptional response of gene to a given environmental or genetic factor. Integration of genomic and transcriptomic data provides more detailed picture of molecular evolution. This chapter describes comprehensive study using the wild relative of cassava ancestor, recognition of natural morphological trait changes during domestication, and gene expression of cassava storage root.
Part of the book: Cassava
In 2019, nearly 690 million people were hungry, indicating that the achievement of Zero Hunger by 2030 is not on-track. The enhanced conservation and use of crop diversity, which demonstrably improves farm productivity and hence food security and nutrition, could be one of the solutions to this problem. The broadening of the inter- and intra-specific diversity of crops contributes to dietary diversification and nutrition and improves the resilience of production systems to shocks, especially the biotic and abiotic stresses attributed to climate change. Examples of successful interventions that resulted in enhanced on-farm crop diversity are provided. Relevant tools and guidelines to strengthen national capacities for the enhanced on-farm management of plant genetic resources for food and agriculture are also highlighted. Guidance, based primarily on the Second Global Plan of Action for Plant Genetic Resources for Food and Agriculture, is presented to enable the conservation of farmers’ varieties/landraces, their genetic improvement and seed delivery systems; promote their cultivation, consumption and marketing; develop and implement policies; foster partnerships and strengthen requisite institutional and human capacities. Finally, the case is made for research and development, including using modern techniques, to achieve these aims.
Part of the book: Landraces