Rationale of the selection and breeding approaches adopted in the CFC/ICCO/IPGRI project
Selection of cocoa clones started in Indonesia and Trinidad in the 1930s. Cocoa breeding efforts between the 1960s and 1990s have however mainly relied on the selection of hybrid varieties, generally made up of mixtures of crosses between locally selected and introduced accessions. More recently, clone selection has made a comeback, aiming at quick genetic gains for priority selection traits (productivity, quality, resistance to disease and pests). Main problems encountered in the 1990s were: low adoption rate of improved varieties, limited characterization and evaluation of existing collections, high susceptibility of most planting material to prevailing diseases and pests, low prices of cocoa and, hence, a significant reduction in cocoa breeding efforts worldwide. Studies between the 1970s and the 1990s have indicated substantial variation in germplasm collections, and relative stability and predominantly additive inheritance of selection traits. These findings suggest that good progress can be expected from collaborative efforts in cocoa breeding, from enlarged evaluation of germplasm collections, from selection of clones in superior progenies and from application of breeding approaches allowing for accumulation of favourable genes. These approaches have been at the basis of the main activities proposed in the CFC/ICCO/IPGRI project, i.e. large-scale evaluation of germplasm collections, establishment of clone trials (International Clone Trial, Local Clone Trials and Observation Plots), Hybrid Trials (using best available clones as parents), germplasm enhancement for black pod (Phytophthora pod rot or Ppr) resistance and population breeding approaches (involving recurrent selection).
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| Format: | book_section biblioteca |
| Language: | eng |
| Published: |
CFC
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| Subjects: | F30 - Génétique et amélioration des plantes, U30 - Méthodes de recherche, A50 - Recherche agronomique, |
| Online Access: | http://agritrop.cirad.fr/537696/ http://agritrop.cirad.fr/537696/1/ID537696.pdf |
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| Summary: | Selection of cocoa clones started in Indonesia and Trinidad in the 1930s. Cocoa breeding efforts between the 1960s and 1990s have however mainly relied on the selection of hybrid varieties, generally made up of mixtures of crosses between locally selected and introduced accessions. More recently, clone selection has made a comeback, aiming at quick genetic gains for priority selection traits (productivity, quality, resistance to disease and pests). Main problems encountered in the 1990s were: low adoption rate of improved varieties, limited characterization and evaluation of existing collections, high susceptibility of most planting material to prevailing diseases and pests, low prices of cocoa and, hence, a significant reduction in cocoa breeding efforts worldwide. Studies between the 1970s and the 1990s have indicated substantial variation in germplasm collections, and relative stability and predominantly additive inheritance of selection traits. These findings suggest that good progress can be expected from collaborative efforts in cocoa breeding, from enlarged evaluation of germplasm collections, from selection of clones in superior progenies and from application of breeding approaches allowing for accumulation of favourable genes. These approaches have been at the basis of the main activities proposed in the CFC/ICCO/IPGRI project, i.e. large-scale evaluation of germplasm collections, establishment of clone trials (International Clone Trial, Local Clone Trials and Observation Plots), Hybrid Trials (using best available clones as parents), germplasm enhancement for black pod (Phytophthora pod rot or Ppr) resistance and population breeding approaches (involving recurrent selection). |
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