Drought responses of traditional and modern wheats in different phenological stages

Drought is one of the most pressing issues in many regions worldwide. Selecting wheat genotypes adapted to changing climatic conditions is crucial for sustainable agricultural production, economic development, and food security. In this study, 156 bread wheat genotypes, including landraces from Turkey, Iran, and Afghanistan, which have adapted to changing climatic conditions for thousands of years, and high-yielding modern wheat varieties, including advanced breeding lines and cultivars were evaluated. The genotypes were subjected to seasonal drought treatments under rain shelters, including pre-heading drought (T1), post-heading drought (T2), irrigation based on long-term precipitation (T3), and seasonal precipitation and supplemental irrigation (T4). Grain yield and physio-morphological and quality traits of the genotypes under seasonal drought and irrigated conditions were evaluated. Drought treatments reduced yield and some physio-morphological traits and increased quality traits. Pre-heading drought treatments had the greatest effect on yield and physiomorphological traits while post-heading drought treatments had the greatest effect on quality traits. Modern wheat cultivars had higher grain yields compared to landraces, but some landraces had a lower yield loss compared to modern wheats under drought stress. The higher tillering rate of the landraces resulted in greater biomass production, taller plant height, and peduncle length. Landraces had higher protein content in all treatments, whereas modern wheats had higher protein content in T2 treatments due to the selection pressure that has been ongoing for years. In summary, given that different drought scenarios will be encountered in the future, landraces should be effectively used in the breeding programs to develop seasonal drought-tolerant modern or climate-resilient wheat varieties.