Résumé
Adaptation of fruit trees to abiotic constraints is a new challenge for fruit production, in particular where water scarcity is likely to occur. In this context, we initiated a research program which aims at screening tree response to soil water restriction within large genetic populations. A bi-parental apple tree progeny was studied in field conditions under contrasted irrigation regimes in order to compare morphology and transpiration of different genotypes in soil water restriction vs well watered conditions. Morphological responses of tree growth were observed during the first two years of tree growth whereas remotely-sensed images were acquired by Ultra-Light Aircraft (ULA) and Unmanned Aerial Vehicle (UAV) during four years. Ortho-images were simultaneously acquired in thermal infrared (TIR), near infrared (NIR) and visible (RGB) bands, in order to extract vegetation and water stress indices. Water deficit index (WDI) which reflects the ratio of actual to potential evapotranspiration was computed at repeated times during the summer season and compared to stem water potential. WDI and vegetation indices were used to classify individual genotype behaviors. Based on a genetic map already available, QTL were detected for morphological responses at young tree stage and are under investigation for WDI and vegetation indices at adult stage. Potential applications for plant breeding and future development of screening in controlled conditions on a core collection of French varieties will be discussed. Work supported by FruitBreedomics project (FP7), APMed project (ARimNet), HiriFap (OpenSciences, Agropolis Fundation) (Texte intégral)