Cassava (Manihot esculenta Crantz)

Cassava is a key food security staple and a competitive feedstock for multiple industrial processes and end uses. Farmers grow hybrids which are reproduced vegetatively. Several programs have used the same breeding scheme for the last 40 years. Significant progress has been made, particularly with t...

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Main Authors: Ceballos, H., Hershey, Clair H.
Format: Book Chapter
Language:Inglés
Published: Springer 2017
Subjects:
Online Access:https://hdl.handle.net/10568/89191
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author Ceballos, H.
Hershey, Clair H.
author_browse Ceballos, H.
Hershey, Clair H.
author_facet Ceballos, H.
Hershey, Clair H.
author_sort Ceballos, H.
collection Repository of Agricultural Research Outputs (CGSpace)
description Cassava is a key food security staple and a competitive feedstock for multiple industrial processes and end uses. Farmers grow hybrids which are reproduced vegetatively. Several programs have used the same breeding scheme for the last 40 years. Significant progress has been made, particularly with the first improved varieties released in the 1980s and 1990s. However, gains slowed down since then. Biotechnology tools, after more than two decades, have not yet had impact on increasing yields. Results from ongoing genomic selection show promising results for high-heritability traits, but not for fresh root yield (FRY). Key challenges to increase FRY are the strong influence of nonadditive genetic effects and the heterozygous nature of breeding parents. There is large within-family variation masking the true breeding value of each progenitor. To improve yields, breeding must shift from making crosses where breeders hope to find hybrids that are superior to those already available (a strategy that has made only slow progress in the last decade or two) to develop and improve inbred progenitors that can produce more reliably better hybrids. The use of inbred progenitors and implementation of reciprocal recurrent selection should be an efficient way to exploit heterosis and epistasis, which are large components in the determination of FRY. Induction of flowering would also accelerate genetic gains. In the near-term future, available molecular markers can be used to improve the breeding value of progenitors rather than in selection of segregating progenies. They can also be used to screen germplasm collections in search of useful traits.
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spelling CGSpace891912025-03-13T09:44:14Z Cassava (Manihot esculenta Crantz) Ceballos, H. Hershey, Clair H. manihot esculenta cassava plant viruses african cassava mosaic virus viruses disease control selection index polyploid índice de selección virus control de enfermedades poliploidia Cassava is a key food security staple and a competitive feedstock for multiple industrial processes and end uses. Farmers grow hybrids which are reproduced vegetatively. Several programs have used the same breeding scheme for the last 40 years. Significant progress has been made, particularly with the first improved varieties released in the 1980s and 1990s. However, gains slowed down since then. Biotechnology tools, after more than two decades, have not yet had impact on increasing yields. Results from ongoing genomic selection show promising results for high-heritability traits, but not for fresh root yield (FRY). Key challenges to increase FRY are the strong influence of nonadditive genetic effects and the heterozygous nature of breeding parents. There is large within-family variation masking the true breeding value of each progenitor. To improve yields, breeding must shift from making crosses where breeders hope to find hybrids that are superior to those already available (a strategy that has made only slow progress in the last decade or two) to develop and improve inbred progenitors that can produce more reliably better hybrids. The use of inbred progenitors and implementation of reciprocal recurrent selection should be an efficient way to exploit heterosis and epistasis, which are large components in the determination of FRY. Induction of flowering would also accelerate genetic gains. In the near-term future, available molecular markers can be used to improve the breeding value of progenitors rather than in selection of segregating progenies. They can also be used to screen germplasm collections in search of useful traits. 2017 2017-11-01T19:47:28Z 2017-11-01T19:47:28Z Book Chapter https://hdl.handle.net/10568/89191 en Limited Access Springer Ceballos, Hernan; Hershey, Clair H.. 2017. Cassava (Manihot esculenta Crantz) . In: Campos, H., Caligari, P.(eds). 2017. Genetic Improvement of Tropical Crops. Springer, p. 129-180.
spellingShingle manihot esculenta
cassava
plant viruses
african cassava mosaic virus
viruses
disease control
selection index
polyploid
índice de selección
virus
control de enfermedades
poliploidia
Ceballos, H.
Hershey, Clair H.
Cassava (Manihot esculenta Crantz)
title Cassava (Manihot esculenta Crantz)
title_full Cassava (Manihot esculenta Crantz)
title_fullStr Cassava (Manihot esculenta Crantz)
title_full_unstemmed Cassava (Manihot esculenta Crantz)
title_short Cassava (Manihot esculenta Crantz)
title_sort cassava manihot esculenta crantz
topic manihot esculenta
cassava
plant viruses
african cassava mosaic virus
viruses
disease control
selection index
polyploid
índice de selección
virus
control de enfermedades
poliploidia
url https://hdl.handle.net/10568/89191
work_keys_str_mv AT ceballosh cassavamanihotesculentacrantz
AT hersheyclairh cassavamanihotesculentacrantz