Wild barley (Hordeum vulgare L. subsp. Spontaneum (C. Koch) Thell.): a noxious weed species in Iran and an untapped genetic resource for barley cultivar development- molecular approach

Wild barley is a weed species descended from a shared ancestor of cultivated barley (Hordeum vulgare). Originating in the Fertile Crescent of the Middle East. H. vulgare L. subsp. Spontaneum (C. Koch) Thell is now widely distributed in the western region of Iran, along the Zagros mountain range. However, on one hand, wild barley has become a problematic, difficult-to-control noxious weed in Iran's wheat fields over the past two decades, causing significant damage to the country's cereal production. On the other hand, the phenotypic and genetic diversity demonstrated among Iranian wild barley populations makes them a valuable genetic resource for barley improvement. This review article discusses strategies for controlling this weedy plant and examines the ecology, phenotypic plasticity for adaptation to harsh environments, and genetic diversity in wild barley populations, all of which make wild barley an invaluable genetic resource. Temperature and rainfall play important roles in natural selection pressures in populations of wild barley, driving the maintenance of genetic variation between environments. Wild barley could serve as a model plant species for studying the relationship between genomic diversity, physiological adaptability to terrestrial habitats, and geographical divergence in grass species. The high level of phenotypic variation in traits, such as disease resistance, environmental stress tolerance, and herbicide resistance in Iranian wild barley indicates an untapped, rich, and extensive source of genetic variation for improving traits in H. vulgare cultivars.