Genotype × environment interactions for root depth of wheat

► G × E for root depth was assessed for 24 wheat genotypes in 6 field environments. ► Soils had either a sudden or gradual increase in soil strength with depth. ► G × E interaction accounted for 40% of total variance compared with 12% for G. ► 3 environment and 6 genotype groups were identified that varied in patterns of root depth. ► Different root trait combinations were needed for different soil environments.