Cassava Genetic Improvement

Abstract

PREFACEThis Handbook is the result of a combined effort by several current and previous cassava researchers at CIAT to review and summarize the most important results of cassava research during the past 40 years. Most of the chapters are based on the various presentations during the Regional Cassava Training Course, held in Thailand from October 6 to 17, 2008. This course was organized upon the realization that many people that were actively involved with cassava research in the 1970s and 80s, both at CIAT and in national programs, have now retired or will soon do so, and that a whole new generation of cassava researchers are currently being hired to take their place.As cassava is now becoming a very important, and mostly industrial, crop in Asia, there are many new opportunities, but also a host of new problems and challenges. These include the appearance in Asia of new cassava diseases and pests; the decreasing availability and increasing cost of rural labor, resulting in the need for partial or complete mechanization of cassava production; the rapidly increasing demand for cassava roots for production of food, feed and fuel, and the unavailability in many countries of new land for any expansion of cassava area, thus requiring a rapid increase in cassava yields to increase supplies. This requires a renewed focus on cassava research for the development of new higher-yielding varieties and more sustainable production practices.While many cassava researchers in national programs in Asia received individual or group training at CIAT-Colombia during the 1970s and 80s, this training was greatly reduced during the following two decades due to funding limitations. Thus, the objective of the Regional Cassava Training Course in 2008 was to provide a new training opportunity for young scientists in Asian countries, and to hand over the knowledge and experience of the older cassava researchers, mostly from CIAT, to a new generation that will have to face the new challenges. Thus, the course was taught mostly by current or already retired CIAT cassava researchers, while the 60-plus participants of the course included cassava researchers from Cambodia, China, East Timor, India, Indonesia, Lao PDR, Malaysia, Myanmar, the Philippines, Thailand and Vietnam. The training course not only provided knowledge -from physiology and biotechnology to animal feeding and production of fuelethanol -but also an opportunity for people from different institutions and countries to get to know each other, which will greatly facilitate future collaboration.Course participants returned home with a CD containing the PowerPoint presentations of the course. However, it was felt that a more comprehensive review of all the topics covered was warranted, as this would provide more in-depth knowledge for those working in the various specialized fields. Most of this information is available in many refereed journals, in workshop proceedings and old CIAT annual reports, but many of these are now out of print or otherwise difficult to obtain. Thus, the Cas...

Adaptation of Cassava to Changing Climates

“…The species originated in South America (Allem et al 2001;Olsen and Schaal 2001) and was domesticated less than 10,000 years ago. With the creation of the International Institute of Tropical Agriculture (IITA) in Nigeria and the International Center for Tropical Agriculture (CIAT) in Colombia in the early 1970s, a new era began for cassava with the implementation of successful breeding projects, modernization of cultural practices, and development of new processing methods (Cock 1985;Jennings and Iglesias 2002;Ceballos et al 2007). National research centers in Brazil, China, Colombia, Cuba, India, Nigeria, Thailand, Uganda, and Vietnam among many other countries have also conducted successful research on cassava.…”

“…The main cassava-growing areas of the world were described by Ceballos et al (2007). Cassava is a perennial species grown as an annual crop.…”

Inbreeding enhances field resistance to cassava brown streak viruses

“…That study also observed S 1 individuals with higher dry matter content and harvest index compared to S 0 . Desirable phenotypes have also been previously reported in S 1 cassava (Ceballos et al, 2004(Ceballos et al, , 2007. Inbreeding, therefore, presents opportunities to improve traits in cassava especially those that are quantitative in nature.…”

Enhancing Nutritional Quality in Crops Via Genomics Approaches

“…Cassava (Manihot esculenta Crantz) plays an important role in the tropics where it is the main source of calories and income for about 800 million of the world's poorest people. Even though the starchy roots of cassava are a valuable source of low-cost energy, their nutritional value is limited as they are poor in protein and essential micronutrients such as iron, zinc, or provitamin A (Ceballos et al 2007). The roots of nearly all commercial cassava cultivars and breeding populations are white, however natural genetic variation exists in the crop and some yellow-rooted cultivars and landraces have been identified that produce provitamin A carotenoids (Chávez et al 2005;Esuma et al 2012).…”