Impact of soil and climate on barley (Hordeum vulgare L.) salinity tolerance in diverse arid and saline conditions

Although barley is the fourth most cultivated cereal and is crucial for food and feed, its yields suffer in saline and arid environments due to drought and salinity, despite its tolerance. This study examines how pedoclimatic factors shape salinity tolerance in barley across different arid environments. Forty barley genotypes from the Middle East-North Africa and Pakistan were tested over two growing seasons in both semi-arid and arid locations. Crops were irrigated with saline groundwater (13 dSm^-1) or non-saline water (2 dSm^-1). Grain yield reduction served as a stress tolerance index. High temperatures exceeding 30 °C and solar radiation during various barley growth stages acted as climate indicators, while soil Potassium (K⁺)and Calcium (Ca²⁺) contents were considered soil indicators. High temperatures (> 30 °C) and intense solar radiation during meiosis-anthesis negatively affect barley's salinity tolerance. Notably, solar radiation was the only climatic factor that significantly impacted even the tolerant genotypes, underscoring its critical role in determining stress sensitivity during this phase. Conversely, high soil levels of K⁺ and Ca²⁺ positively influence salt tolerance. The research also revealed a significant correlation (R² = 0.69) between barley's salt tolerance and the salinity of the genotypes' geographic origin. The findings highlight the need to harness natural forces in crop selection and implement tailored, sustainable agronomic practices, including adequate potassium and calcium fertilization.