Wild barley (Hordeum spontaneum), the immediate wild progenitor of cultivated barley (H. vulgare), originated in the Fertile Crescent and remains widespread from the Eastern Mediterranean to Central Asia. This diploid grass possesses a brittle rachis, enabling natural seed dispersal. As the ancestor to all domesticated barleys, it represents a crucial genetic reservoir harboring rich diversity for drought tolerance, disease resistance (e.g., powdery mildew, rust), and abiotic stress adaptation. Modern breeding programs extensively utilize H. spontaneum to introgress these valuable wild traits into elite cultivars, significantly enhancing the resilience and yield stability of barley under challenging climatic conditions.