The Rising Importance of Hulless Barley in Human Nutrition and the Need for Improved Agronomic Practices

The cultivation requirements of hulless barley, whose importance and utilization in human nutrition are increasing, are not yet widely known. Before newly developed varieties are adopted by farmers, it is critical to assess their regional adaptability and agronomic characteristics to help prevent potential yield, quality, and economic losses. In this regard, two newly registered two-row hulless barley cultivars Yalın (winter type) and Özen (spring type) were evaluated based on different sowing densities. The research was conducted during the 2015–2016, 2016–2017, and 2018–2019 growing seasons at the Central Research Institute for Field Crops (TARM), Gölbaşı/İkizce Research and Application Farm, under a fallow–cereal cropping system. The experimental design was a randomized complete block with three replications. Five different seed densities were tested for each cultivar: 300, 400, 500, 600, and 700 seeds m⁻² for Yalın; and 350, 450, 550, 650, and 750 seeds m⁻² for Özen. The study evaluated yield and yield components (plant height, number of plants and spikes per square meter, biological yield, harvest index, and grain yield), as well as quality parameters such as hectoliter weight, thousand-kernel weight, sieve retention value, grain size classification, protein content, and beta-glucan content. Optimum plant density was determined in terms of physical yield and seed production potential. Grain yield in the Yalın cultivar ranged between 294.61 and 378.75 kg da⁻¹. The highest grain yield (378.75 kg da⁻¹) was obtained at a seeding rate of 700 seeds m⁻². The economic optimum seed rate was determined as 540.37 seeds m⁻², which corresponded to an estimated grain yield of 357.50 kg da⁻¹. In the Özen cultivar, grain yield ranged between 177.35 and 216.08 kg da⁻¹. The highest grain yields (213.78 and 216.08 kg da⁻¹) were achieved at seeding rates of 650 and 750 seeds m⁻², respectively. The economic optimum seeding rate was determined as 568.34 seeds m⁻², at which a grain yield of 206.68 kg da⁻¹ was estimated.