Differences in Salinity Tolerance in Avena sativa and Avena nuda

Both Avena sativa and Avena nuda, which are highly valued for their use in food and fodder, demonstrate considerable potential in the management of saline-alkali soils. This study aimed to establish a foundation for the selection of salt-tolerant oat cultivars by assessing the impact of varying salt concentrations (0, 50, 100, 150, and 200 mmol L−1) on agronomic traits, photosynthetic characteristics, physiological and biochemical properties, and leaf anatomical structures in both covered oat cultivars and naked oat cultivars. The measured parameters indicate the level of salt tolerance in Avena sativa and Avena nuda, which is influenced by both salt concentration and cultivar. Both Avena sativa and Avena nuda demonstrate strong adaptation to mild and moderate salt stress conditions. However, Avena sativa exhibits a significantly greater capacity to withstand severe salt stress compared to Avena nuda. Affinity function analysis ranked the cultivars’ salt tolerance as follows: ‘Qinghai 444’ > ‘Mengyan No. 1’ > ‘Baiyan No. 18’ > ‘Qingyin No. 3’. These results suggest that the selection of oat cultivars for salinity improvement should be tailored to the specific salinity levels present in different regions.