My scientific interest lies in understanding how plant phenotypes are shaped by the environment (plasticity), how these plastic responses vary among genotypes (genotype-by-environment interactions; GxE), and how GxE interact with selection and adaptation. My work is at the interface of two disciplines: ecophysiology (providing mechanistic understanding of the control of traits by environmental variables) and quantitative genetics (revealing the genetic architecture underlying variation in complex traits).
In my thesis, I focused on flowering time in maize (Zea mays ssp. mays). I developed a model to extract genotype-specific parameters for flowering time responses to temperature and photoperiod. The purpose was to understand how selection has shaped flowering time plasticity to offer new perspectives in breeding for adaptation. Applied at multiple genetic scales (populations, genotypes, and haplotypes), this model provided three main conclusions. First, due to development × environment interactions, different genotypes grown together within a naturally fluctuating environment can sense and respond to substantially different environmental cues, which should be accounted for when modeling GxE across environments. Second, using a diversity panel to examine the trait space for flowering time, I discovered that tropical and temperate germplasm occupy distinct regions within the space, revealing physiological footprints of maize adaptation. Third, applying this model to a series of populations independently selected for early flowering across a photoperiod gradient, I demonstrated that flowering time responses to temperature and photoperiod sensitivity are uncoupled (not pleiotropic) at genetic and physiological scales.
Following my thesis, I began a post-doctoral position in the CERES team, where I focused on determining the genetic control of root trait plasticity in response to drought in pearl millet (Pennisetum glaucum (L.) R. Br.). Building on the concepts developed during my thesis, I established a new metric to characterize the drought stress experienced by a diversity panel across both stressed and irrigated fields. This allowed me to derive a measure of plasticity magnitude, which helped distinguishing root traits that exhibited plasticity in response to soil water content. These traits were specifically related to the meta-xylem. For these traits, I conducted single-environment genome-wide association studies (GWAS) to identify genetic markers (SNPs) associated with their intrinsic regulation. Additionally, I used the plasticity magnitude measure as a phenotypic trait in GWAS and integrated these results with multi-environment genome-wide analyses to identify SNPs associated with the plastic response of these traits. This approach will contribute to a better understanding of the genetic architecture underlying root trait plasticity. To assess the adaptive significance of these SNPs, I will examine their co-localization with yield-related QTLs and QTLs identified through genome-environment association analyses.
