Diversity within a crop of self-pollinating species can provide advantages in sustainable farming, including the ability to adapt to environments. However, few results proving the benefits in various species and climatic conditions are available. Our aim was to find the differences between heterogeneous and homogeneous materials and determine if crossing has advantage over mixing. We compared essential traits of twelve heterogeneous spring barley composite cross populations (CCPs) to those of seven mixtures representing similar genetic backgrounds and five homogeneous varieties in nine organic and three conventional environments over the course of three years. We found significant advantages for heterogeneous materials, particularly CCPs, for yield in organic and stress environments as well as yield stability, N utilisation efficiency, protein content, 1000-grain weight, and net blotch severity and observed positive trends for N uptake efficiency and weed competitiveness. CCPs’ advantages over mixtures were for protein content and 1000-grain weight, a nonsignificant yield gain in low-yield and stress environments, higher yield stability, and minor positive trends for net blotch, NUE, and weed competitiveness. We suggest heterogeneous populations as valuable alternatives to uniform varieties for organic and poor cultivation environments. Although multi-component mixtures could provide a performance similar to CCPs, considering the adaptation potential, populations would be more advantageous overall.

Over recent decades, the cereal grain market has experienced notable changes