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Cirad

Genetic adjustment to changing climates: Rice

Lafarge T., Peng S., Hasegawa T., Quick W.P., Jagadish K.S.V., Wassmann R.. 2011. In : Yadav Shyam S. (ed.), Redden Robert J. (ed.), Hatfield Jerry L. (ed.), Lotze-Campen Hermann (ed.), Hall A.E. (ed.). Crop adaptation to climate change. Chichester : Wiley-Blackwell [Royaume-Uni], p. 298-313.

This review addresses the response of rice plants to (i) elevated CO2 concentrations, (ii) higher temperatures, especially nocturnal temperatures, and (iii) the interaction of both factors in view of possible improvements of rice germplasm for adaptation to climate change. Elevated [CO2] affect both, stomatal conductance and photosynthesis apparatus, resulting in associated gains in the different levels of plant growth (leaf level photosynthesis > canopy level > yields). Positive CO2 impacts, however, decrease over the ontogenetic development of rice plants. This 'down-regulation' of photosynthetic rates under elevated [CO2] is an important factor for assessing net impacts and, in the next step developing improved rice germplasm for elevated ambient [CO2]. Higher night time temperatures are associated with lower rice yields; the most plausible hypotheses for this effect is the loss of carbohydrates through respiration which increases with crop stage and the detrimental responses in plant phenology and carbohydrates partitioning, however, some additional studies are needed to better understand the crop response to high night temperature. While the impact of elevated [CO2] on crop performance will be positive, higher day and night temperatures will reduce biomass accumulation, affect carbohydrates partitioning and remobilization, generate less affective plant morphology, and finally overcome the positive effect of elevated [CO2]. Overall, the positive response of C3 plants like rice to elevated [CO2] can be seen as a crucial mechanism to compensate or even supersede detrimental effects of future climatic conditions. It is then essential to account for the interaction of elevated [CO2] and higher temperature, and to identify its genetic control, in order to develop improved germplasm with stage-specific traits that (i) tap the full potential of elevated [CO2] for photosynthesis and (ii) improve crop performance under higher temperatures. (Résumé d'auteur)

Mots-clés : adaptation aux changements climatiques; oryza sativa; tolérance à la chaleur; température; dioxyde de carbone; génétique; changement climatique; oryza

Thématique : Génétique et amélioration des plantes; Météorologie et climatologie; Physiologie et biochimie végétales

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