MRI method to evaluate effects of water stress on potato tubers during growing

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED [ADD1_IRSTEA]Sûreté alimentaire

International audience

English. Drought is a major problem affecting agricultural practices as a result of global warming. Potato is considered as a drought sensitive crop, which results in loss of yield and tuber quality. Further, water shortage may induce physiological disorders such as glassy tubers and internal rust spots. Potato response to drought is complex: it depends on cultivar, climatic and soil conditions and water stress timing within the growing period. Characterization of plant adaptive responses is a major issue in the field of phenotyping. There is therefore a demand for the emergence of analytical techniques that are non-invasive, allowing better performance of this phenotyping.In the current work, MRI was used to evaluate the effects of water stress on potato tubers by in situ monitoring of tubers growth kinetics during an eight-week period. In this respect, potato plants were cultivated in pots under controlled and stressed conditions. In the latter case, irrigation was monitored in a way to simulate cultivation of potatoes during drought seasons. The stress experienced by plant was evaluated through the monitoring of soil water potential and soil humidity. 3D morphological images of the underground part of the potato plant in pots were recorded on a 1.5 T MRI scanner (Avanto, Siemens) using a fast spin echo sequence (Fig. 1). The objectives were i) to evaluate the effect of water stress on the individual growth kinetics of tubers and ii) to detect the stage at which rust spots appear and monitor their evolution until harvest.The approaches developed in the present study were shown to be effective to characterize tuber development and quality, providing a quantitative analysis of morphological features of tubers. The results were discussed from the perspective of applying this methodology for phenotyping of plant under water shortage.