Impact d’un stress hydrique suivi d’une phase de récupération sur la tomate cultivée (Solanum lycopersicum), une espèce sauvage apparentée (Solanum chilense) et leurs hybrides F1 et F2

Details

Supervisors

Quinet, Muriel

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en sciences agronomiques, à finalité spécialisée

Abstract

Climate change is leading to more frequent extreme weather events, such as droughts, which are having a negative impact on global agriculture. The cultivated tomato (Solanum lycopersicum), a major economic species, is particularly sensitive to water stress. Over time, its domestication has created a genetic bottleneck that has eliminated traits related to its resistance to abiotic stresses. For these reasons, it is relevant to look at wild relatives of the cultivated tomato with a view to improving it. The wild tomato species studied in this master thesis is Solanum chilense, a plant that originated in particularly arid environments of South America. The fact that it thrives in this type of environment makes it an interesting candidate for introgressing resistance genes into cultivated tomatoes. The aim of this study is to analyse the impact of water stress followed by rehydration on four generations: Solanum lycopersicum, Solanum chilense, and their F1 and F2 hybrids. The first objective of this work is to assess whether the impact of water stress differs between the four generations. A second objective was to compare the behaviour of the hybrids with that of the two parent plants. Finally, we wanted to see whether the two F1 and F2 genotypes showed different behaviours, with the aim of establishing a resistance gradient. To do this, plants of S. lycopersicum, S. chilense and their hybrids were subjected to two water regimes (stressed and control). Morphological and physiological measurements were taken to assess the effects of stress and rehydration. Overall, different strategies were observed between generations. Depending on the parameters, the same plants did not always prove to be the most resistant. S. lycopersicum showed results suggesting that it coped well with the stress. S. chilense also resisted the stress well, even though the sample studied was limited. Great variability in response was visible in the hybrids, particularly in the stressed F2 plants, showing that second-generation hybrids can display interesting characteristics. Unfortunately, the lack of individuals did not allow us to draw any conclusions about the resistance of the two F2 genotypes. Future studies on hybrids using larger samples would certainly reveal clearer trends.