Vales Michel, Chatel M.H., Borrero Jaime, Ospina Yolima.
1999. Recurrent selection for rice (Oryza sativa)blast (Magnaporthe grisea) resistance in populations with narrow genetic base.
In : Proceedings of the International Symposium on Rice Germplasm Evaluation and Enhancement, August 30 - September 2, 1998, Stuttgart, Arkansas. Eds. J.N. Rutger, J.F. Robinson, R.H. Dilday
Résumé : Recurrent selection is used to enhance populations with large genetic base (PLB) for polygenic traits like partial blast resistance. If the selection index is too high there is a risk of loosing useful genes not still in favorable genetic associations. The selection index has to be moderate, so recurrent selection breeding using PLB is a long-term process. The use of recurrent selection in populations with narrow genetic base (PNB) is a mean to avoid the risk of loss of useful genes and speed-up the genetic progress at medium-term. To develop PNB the first step is to select few parents with the highest known level of expression of a specific trait, for example IRAT 13 for partial blast resistance. At the end of the recurrent selection process the fixed lines would present each trait at the corresponding parent level, for example the partial resistance level of IRAT 13. Advantages. In comparison with the use of F2 populations the potential genetic progress is better because the recurrent cycles permit the use of the best parent for each individual trait, without warring for its other qualities. In comparison with the use of PLB the genes are less diluted so the use of PNB requires less time for the development of good lines. The risk of genetic derive is also reduced, and it is possible to fix the PNB for oligogenic traits before the starting of the recurrent selection breeding. The live of PNB is short, so it is easier make new populations than adapt old ones to follow objective changes. Disadvantages. In comparison with the use of F2 populations more time is needed to develop fixed lines because the first step is to enhance the PNB before the pedigree selection. The recurrent selection method is not adapted to the breeding for oligogenic traits. In comparison with the use of PLB the potential genetic progress is reduce. The use of PNB is a technical compromise between the use of F2 populations and PLB use. The three types of population are complementary parts of a same general breeding scheme. (Texte intégral)
Mots-clés Agrovoc : Oryza sativa, Magnaporthe grisea
Classification Agris : F30 - Génétique et amélioration des plantes
H20 - Maladies des plantes
Auteurs et affiliations
- Vales Michel, CIRAD-CA-CALIM (COL)
- Chatel M.H., CIRAD-CA-CALIM (COL)
- Borrero Jaime, CIAT (COL)
- Ospina Yolima, CIAT (COL)
Autres liens de la publication
Source : Cirad - Agritrop (https://agritrop.cirad.fr/563937/)
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