Genetic regulation of leaf ionomics in millet and its response to drought. Supervised by L. Laplaze / co-supervised by Y. Vigouroux and A. Grondin
Millet (Cenchrus americanus) is a food crop in arid areas and a model for studying plant adaptation to water stress. This thesis focused on the genetic determinants of leaf ion accumulation in millet and their interaction with drought. Field trials were conducted with a panel of 165 genetically fixed lines from the PMiGAP-WCA panel grown under irrigated and drought conditions for two years in Senegal. The plants were phenotyped for root and agromorphological traits as well as for ion content in the last ligulate leaf. We observed high genotypic variability in leaf ion concentrations, associated with root and agromorphological traits. Genetic association studies identified genomic regions and candidate genes involved in mineral accumulation, with some loci showing drought-specific effects. The results highlight the impact of genotype-environment interactions and identify promising genotypes with stable ionomic profiles under stress. This research provides new insights into the physiological and genetic basis of millet mineral nutrition, supporting breeding strategies for more resilient and nutritionally efficient varieties in regions facing climatic challenges.
