Maize drought responses across experimental scales: linking above- and belowground traits

Drought stress is an increasingly dominant constraint on maize (Zea mays L.) production under changing climatic conditions. While modern hybrid varieties are optimized for high yield potential, their performance often declines under variable and limited water availability. This limitation is particularly pronounced during early developmental stages. In contrast, maize landraces may express adaptive root and rhizosphere traits; however, the consistency of these responses across contrasting environmental conditions remains poorly understood. In this study, we investigated variety-specific drought responses in maize by integrating controlled greenhouse experiments with complementary field trials. In a high-throughput phenotyping facility, six maize varieties representing contrasting breeding histories were grown under five distinct water regimes and two soil types. We quantified growth dynamics of above- and belowground biomass, functional root and shoot traits including plant height, biomass allocation, and root morphological properties, as well as physiological responses to characterize drought-response strategies under controlled conditions. To date, the data suggests pronounced soil-type effects on root and shoot traits. In addition, variety-specific patterns emerge for selected above- and belowground traits across the two soil types. Additionally, field experiments were established at four sites in Bavaria to assess genotype performance under realistic agronomic conditions, representing contrasting precipitation and soil textures. To enhance information gain, the field trials included both single-variety and variety-mixture systems, in which maize genotypes with contrasting drought-response strategies were grown either individually or in two-genotype mixtures within the same plot allowing potential genotype interactions under field conditions to be evaluated. By focusing on greenhouse-based trait expression while embedding the study in a field context, this work aims to identify root and rhizosphere traits associated with drought responses and to evaluate their relevance across contrasting environmental conditions. The results contribute to a mechanistic understanding of maize drought adaptation and explore the potential of landraces as genetic resources for the development of maize varieties suited to increasingly dry and variable climates.