Breeding of Root and Tuber Crops

The root and tuber crops cassava, yams and sweet potato are important in Nigeria and Africa. Breeding methods most appropriate to these crops are discussed in terms of mating systems, creation of source populations, selections. Intervarietal hybridization, interspecific hybridization, and population improvement through cyclic selection and recombination procedures are methods of creating source populations. Factors affecting the effectiveness of selection, and efficient methods of selection to make maximum genetic progress are discussed. Use of selections is briefly stated. Synthetics, composites, or single and double crosses of yam produced from true seed may be used at the farmer level. (author)