Résumé
Plant production in the twenty-first century will be altered by climate change in numerous ways, including higher temperature, higher atmospheric [CO2 ], alteration in timing and quantity of water availability. Oil palm yield is particularly affected by water availability, considering often as the main limiting factor. For this reason, efficient and early screening for improved plant drought tolerance, a rather difficult and time-consuming process, seems to be a promise to support breeding programs, especially in perenial plant, e.g. oil palm. The present study aims to explore the role high resolution fluorescence can play as a proxy of leaf photosynthetic capacity maintenance to drought and its genotypic variability. We analyzed the physiological effects of drought on 4 oil-palm progenies at young stage (6 months old in nursery), controlling their stress level by Transpirable Soil Water Fraction (FTSW). Photosynthesis measurement were performed, and evaluation of their water stress sensitivity was done calculating an early indicator with chlorophyll fluorescence. To compare, a field evaluation during the dry season was made analysing the same progenies (5 years old) in photosynthesis measurement for two years. In nursery, the photosynthetic performance index (PI) parameter measured by chlorophyll fluorescence, was used to calculate the drought factor index (DFI), revealing differences between progenies as a function of plant water stress sensitivity. We found that the DFI ranking of the tested varieties was in line with the photosynthetic potential maintenance observed in nursery for the low sensitive progeny, and with the higher net photosynthesis level observed in the field in dry season. Interestingly, progenies showing the higher photosynthesis level in the field were related to an higher yield. (Texte intégral)