Crop Wild Relatives (CWRs) carry genetic traits for resilience, productivity, and nutrition and could play a key role in the agroecological transition of European food systems. In its first 18 months, the COUSIN project is making strong progress towards understanding their potential, unraveling the genetic basis of valuable CWR traits.

Understanding Stress Resilience

COUSIN researchers have launched a wide range of experiments to study how crops and their wild relatives respond to biotic stresses, such as pests and diseases, and abiotic stresses, such as drought and waterlogging.

• Pea : More than 320 accessions (including wild relatives, landraces, and modern varieties) are being tested. Resistance is being evaluated against diseases such as fusarium wilt, aphanomyces root rot, rust, powdery mildew, and ascochyta blight, as well as pests like aphids and parasitic weeds like crenate broomrape. Responses to drought and snail infestations are also being studied by measuring plant water content, photosynthetic efficiency, and pigment concentrations.
• Brassica: Screening of accessions has identified key phenotypic, biochemical, and genetic traits related to stress resistance. The results were documented using standardized descriptors to enable effective sharing and comparison.
• Wheat: Trials are underway to assess tolerance to powdery mildew, yellow rust, Fusarium, and drought. Genetic diversity studies are also highlighting marker-trait associations that could accelerate breeding for disease resistance and resilience.
• Barley: Wild barley accessions are being tested for tolerance to drought, waterlogging, and local biological stresses.
• Lettuce : A collection of 150 accessions of Lactuca serriola is under study to reveal natural mechanisms of resistance to low phosphate conditions in a high throughput phenotyping growth chamber..

Crop performances insights

Beyond stress resilience, trials are investigating how CWRs perform under different farming systems: high-input, low-input, and organic practices. Yield stability over several seasons is also being investigated as well as intercropping strategies. Notably, Brassica macrocarpa is being tested as a biofumigant – a natural soil amendment that can protect tomato crops and reduce reliance on chemical inputs!

Nutritional and health benefits

Wild relatives are also being studied for their nutritional and bioactive compounds:

• Pea wild species (Pisum fulvum, Pisum abyssinicum) are being analysed for protein, antioxidants, saponins, and mineral composition (iron, zinc, magnesium, and others). Results will be compared with domesticated pea (Pisum sativum). A genome-wide association study (GWAS) has also been conducted on 325 accessions to map mineral content variation.
• Brassica accessions are being evaluated for glucosinolates, phenolic compounds, and antioxidant activity, which are linked to both plant defence and human health benefits.
• Wheat analyses are focusing on micronutrient concentrations.
• Wild barley accessions are being studied for phenolics, condensed tannins, mineral composition, and β-glucan, a dietary fibre with known health-promoting effects.

Exploring the genetic and microbial dimension

We have built a new microbiome analysis platform allowing partners to share sequencing data and better understand how soil microbes interact with CWRs. The platform further enable comprehensive diagnostic of microbiome properties, forming the base of precision interventions improving crop performance

From Research to Field

COUSIN is translating these discoveries into pilot projects across Europe. Breeders and farmers are testing new lines of pea, barley, wheat, lettuce, and brassica derived from CWRs. Early results are promising: peas with better disease resistance, barley and wheat with stronger stress tolerance, and brassica and lettuce that thrive in low-input systems.