Abstract

Wheat yield potential, i.e. the yield achieved when the best available technology is used, has increased almost linearly after the sixties, particularly in more favorable environments where soil water availability is not limited. However, most of the wheat is grown under rainfed conditions where the yield potential is reduced due to water scarcity. It has been proposed that potential yield and water-limited potential yield of wheat should continue increasing in order to cope with future food demand, as a consequence of the growing population, and also to mitigate the negative impacts of global climate change on crop productivity. Such challenges remark a clear requirement for new strategies and tools development, in order to identify key traits that can be used in breeding programs to select elite genotypes with better adaptation to adverse environmental conditions. The aim of this project is to provide a deeper understanding of the physiological and molecular mechanisms involved in yield potential and acclimation to water stress of bread wheat grown in Mediterranean environments. We will study a panel of 15 spring wheat genotypes of contrasting yield under water limiting conditions, which were previously selected from a set of 384 genotypes. The specific objectives are: a) to assess physiological responses of this wheat panel grown under water-limited and full irrigation conditions, in particular traits related to the efficient use of water and delay senescence during grain filling; b) to evaluate levels of metabolites and gene expression in leaves of the wheat panel grown under two contrasting water regimes; and c) to predict the genotypic variability of physiological traits and selected metabolites using ground based remote sensing technologies (multi-spectral reflectance and infrared termography). Besides grain yield and agronomic yield components, leaf water and osmotic potential, gas exchange by leaves and spikes, leaf florescence, chlorophyll content, stable isotopes of carbon (δ13C) and oxygen (δ18O) in dry matter (leaves and grains), levels of metabolites (sugars, amino acids and other compounds) and gene expression in leaves will be evaluated. In addition, we will use multi-spectral reflectance (a FieldSpec portable spectroradiometer) in order to associate the spectral signatures of each wheat genotype with relevant physiological traits and metabolites, and infra-red imaginary (infrared thermal camera) to estimate the water status of wheat genotypes growing under water limiting and full irrigation conditions.