MultiStress_SP1

Effect of stress by genotype interactions on above- and belowground carbon allocation, nutrient use efficiency and root-zone processes (SP1)

01/04/2026 to 31/03/2030

Maize (Zea mays L.) is one of the most important staple food crops worldwide. Its productivity depends heavily on the availability of water and nutrients, specifically nitrogen (N), the two most important abiotic deficiency factors in maize cultivation worldwide. Maize is also increasingly exposed to biotic stress factors such as fungal and insect infestation. It is therefore more likely that the productivity of maize will be limited more frequently in future by several stress factors occurring simultaneously. Currently, most modern maize varieties are - at best - bred for tolerance to individual abiotic or biotic stress factors, but not for tolerance to combined stress. This is largely due to the fact that we have little knowledge of the genetic potentials and physiological mechanisms relevant for the responses to multiple stresses. SP1 of the RU MultiStress focusses on the response of above- and belowground biomass production to single and multiple abiotic and biotic stresses and analyses resource use efficiency. The project aims at the phenotypic plasticity of maize with regard to the response to N scarcity, drought, their interactions with each other and their interactions with Setosphaeria turcica and the maize stem borer. The novelty of the project arises from i) the combination of destructive and non-destructive phenotyping methods with respect to above- and
belowground traits and resource allocation across a wide range of genotypes, ii) the combination of this information with transcriptomic and metabolomic methods in collaboration with SP3 and the ZP, respectively iii) the introduction of this qualitative and quantitative information into novel genomic and crop modelling approaches in collaboration with SP6. The strength of SP1 lies in the use of state-of-the-art methods for phenotyping important traits of the aboveground biomass in combination with novel methods to study stress responses in the root and rhizosphere zone, mainly under field conditions in Germany and Kenya. The aim is also to improve the understanding of how above- and belowground stress responses interact, e.g. how assimilate and nutrient allocation changes from the shoot to the roots and rhizosphere, so that plants can better cope with abiotic and biotic stress. Due to the great importance of maize in temperate and tropical climates, our study deals with a broad spectrum of genetic material from both climate zones. The project will provide important information on the genetic variability of stress tolerance and resistance. This will accelerate breeding progress and contribute to
more precise modelling and model-based variety development, which will strengthen maize-based cropping systems in terms of their robustness under changing demographic and climatic conditions.