Salinity, alkalinity and their combined stress effects on germination and seedling growth attributes in oats (Avena sativa)

Context. Under natural field conditions, plants confront the co-occurrence of stresses. A comprehensive insight into combined-stress tolerance is requisite to developing stress resilience in cultivars of oats (Avena sativa L.) for saline-alkaline soil. Aims . This study was undertaken to characterise diverse oat genotypes for seedling growth attributes under two saline and alkaline concentrations and under combined saline-alkaline conditions. Methods. We screened 105 accessions of the genus Avena with the following treatments: control, reverse osmosis water; moderate salinity (50 mM); high salinity (100 mM); moderate alkalinity (15 mM); high alkalinity (30 mM); combined moderate salinity-alkalinity (50 mM + 15 mM); and combined high salinity-alkalinity (100 mM + 30 mM). For saline treatments, NaCl and Na2SO4 salts were used in equimolar concentrations, and for alkaline treatments, NaHCO3 and Na2CO3. Key results. Analysis of variance showed significant (P <= 0.001) variation among treatments and genotypes. Principal component analysis revealed 83.3% of the total genetic variation accounted for in the first two principal components. Correlation analysis showed a significant positive correlation between final germination percentage and seedling vigour index. Stress tolerance index identified tolerant and sensitive oat genotypes under high saline and alkaline stress, and multi-trait stability analysis confirmed the stability of performance of some genotypes under the imposed treatments.Conclusions. According to the stress tolerance index and multi-trait stability analysis, genotypes IG-20-477, OS-377, IG-20-798 and IG-20-575 were found suitable for high saline-alkaline stress.