Effects of Abiotic Stress on Sink and Source Affecting Grain Yield and Quality of Durum Wheat: A Model Evaluation

Abstract

Heat and drought affect grain yield and quality of wheat through sink development and source capacity. Improving grain yield and quality requires an optimization of dynamic interactions of both storage and photosynthetic processes. Seed nitrogen accumulation and the resulting quality traits can be simulated using ecophysiological models. Differences in stress tolerance between genotypes are reflected in individual grain weights and grain yields per culm rather than in rate of leaf photosynthesis. Narrowing the gap between genetic potential and phenotypic expression requires knowledge about the physiological mechanism of increasing sink strength and source capacity A new model to study genotype-by-environment interaction (GECROS) is used to integrate effects of stresses on sink-source processes and on grain yield and quality. GECROS models each process with a consistent level of detail and deals with interactive aspects and feedback mechanisms of crop growth. This applies to photosynthesis-transpiration-coupling via stomatal conductance, carbon-nitrogen interaction on leaf area index, functional balance between shoot and root activities, and the interplay between supply and demand affecting reserve formation and remobilization An evaluation of abiotic stress effects on durum wheat in a Mediterranean climate, aiming at a time-resolved simulation of sink-source interactions during stress periods at different stages of development, will be presented.