Li Zhi-Kang, Shen L.S., Courtois Brigitte, Lafitte Renée Honor.
2000. Development of near isogenic introgression line (NIIL) sets for QTLs associated with drought tolerance in rice.
In : Molecular approaches for the genetic improvement of cereals for stable production in water-limited environments : A strategic planning workshop held at CIMMYT, El Batan, Mexico, 21-25 June 1999, with support from the Rockeffeller Foundation. Ribaut Jean-Marcel (ed.), Poland David (ed.). CIMMYT
Résumé : Two mechanisms are believed to contribute to drought tolerance (DT) in rice. A deep and thick root system in the upland rice lines (japonicas) is largely responsible for their tolerance to drought. Alternatively, a better developed osmotic adjustment (OA) capacity in indica cultivars is considered to be a reliable mechanism to maintain the cell turgor under diminishing leaf water potential, potentially contributing to DT. To test the hypothesis of whether the two different DT mechanisms can be combined through QTL pyramiding, four QTLs (located on chromosomes 1, 2, 7, and 9) identified in a rice DH population were transferred into an indica variety, IR64, using a marker-assisted backcross program. Thirty BC3F3 near isogenic lines with 1-2 introgressed QTLs were obtained and evaluated in a replicated greenhouse experiment for the target root traits and two nontarget traits - number of tillers per plant and plant height. Three of the 4 introgressed QTLs (targets 1, 7, and 9), which were detected with greater LOD previously, were associated with the expected root phenotype, while the other (target 2) was not. The introgressed root QTLs were associated with either reduced tiller number or increased height, but this association was inconsistent, indicating that the observed genetic drag was more likely due to linkage rather than to pleiotropy. The concept and procedure of a new approach the molecular backcross breeding strategy-were proposed that allow simultaneous identification, transfer, and allelic diversity discovery of desirable QTLs. This approach should be able to overcome all the limitations of MAS for QTLs and has all the advantages of the AB-QTL analysis. However, the effectiveness of phenotypic selection for DT in the BC progenies remains the key to success for this approach.
Mots-clés Agrovoc : Oryza sativa, résistance à la sécheresse, marqueur génétique, carte génétique, anatomie végétale, racine, phylogénie
Mots-clés géographiques Agrovoc : Philippines
Mots-clés complémentaires : QTL
Classification Agris : F30 - Génétique et amélioration des plantes
Auteurs et affiliations
- Li Zhi-Kang, IRRI [International Rice Research Institute] (PHL)
- Shen L.S., IRRI [International Rice Research Institute] (PHL)
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Courtois Brigitte, CIRAD-CA-CALIM (PHL)
ORCID: 0000-0003-2118-7102
- Lafitte Renée Honor, IRRI [International Rice Research Institute] (PHL)
Autres liens de la publication
Source : Cirad - Agritrop (https://agritrop.cirad.fr/478925/)
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