Résumé
Most lowland rice in West Africa depends mainly on rainfall for water supply. Drought is consequently one of the major constraints on rice production, drastically affecting both plant growth and development. The objective of this work was to study the impact of water deficit both on canopy temperature and on chlorophyll fluorescence level, used as indicators of transpiration and photosynthetic activity. Measurements using infrared thermography and fluorimetry were taken on both 17 lines resulting from the cross IR64 X B6144F-MR-6-0-0 and their two parents plus one tolerant (APO) controls. These 20 lines were phenotyped after applying a drought constraint in a controlled laboratory environment in Montpellier (France) in 2013 and - 2014 and in field in the lowlands of Banfora and Farako-ba (INERA Burkina Faso) in 2014. Results showed that the drought stress sustained by the plants increased canopy temperature in all lines, entailing differential disturbance of the photosynthetic process, markedly depressed in susceptible lines. A classification of the lines with respect to their sensitivity to stress could be established by using the Drought Factor Index (DFI), and Crop Water Stress Index (CWSI) as was established a correlation between the phenotyping methods by infrared thermography and fluorimetry. This article propose an efficient application of combined imaging as a rapid and accurate phenotyping tool for crop yield improvement, in particular by monitoring the efficiency of plant responses to the fluctuating of environmental conditions. This study proved the efficiency of the method combining IR thermographie and fluorimetry as a field phenotyping tools for drought resistance.