Intercropping is the growing of at least two crop species on the same land for the entire or a substantial part of the growing season (Trenbath et al. 1974, Li et al. 2020). The intercropping of legume and cereal species is particularly appealing for several reasons including yield stabilization and nutritional composition as well as various agro-ecosystem services. However, intercropping does lead to different competition environments for the mixed partners which can severely affect their agronomic performance. The choice of complementary intercropping partners is therefore an important step towards a successful mixed crop harvest. Several recent studies demonstrate the added value of dedicated intercrop breeding in which new varieties are specifically developed as reciprocal intercropping partners (Annicchiarico et al. 2019 , Wolfe et al. 2021). Intercrop breeders face the same challenges as their single-crop counterparts as they need to develop varieties that perform well under a range of environmental conditions. This quest generally implies a search in the so called Genotype-by-Environment (GxE) space for which numerous strategies have been described in literature. However, intercrop breeders are looking for pairs of genotypes belonging to different species which gives rise to a vast GxGxE search space for which no exploitation strategy is currently available. This PhD research project aims to develop dedicated data analysis methods that allow for an efficient exploitation of an intercrop GxGxE space. The project is decomposed in the following consecutive tasks:  Extend and adapt existing statistical methods for GxE modeling (linear-bilinear models including Finlay-Wilkinson, AMMI, GGE and various linear mixed model formulations )  Integrate intercrop concepts (general and specific mixing abilities, producer-associate effects) into GxGxE models This study will be conducted between November 2021 en August 2025. The envisioned scientific output will be most valuable to plant breeding and intercrop research communities around the world.