Identification of distinctive agro-physiological and molecular responses to seawater stress among tolerant and sensitive genotypes of barley

Estimation of phenotypic and genotypic diversity is one of the principal and essential steps in plant breeding programs for detection tolerance of salinity stress. Lysimeter experiments during two growing seasons 2020/2021 and 2021/2022 were carried out to investigate the responses to seawater stress among fifteen barley genotypes based on agronomical, physiological, and Related Amplified Polymorphism (SRAP) marker analysis. Different levels of seawater were used (2.35 dSm(-1) as a control and three salinities levels 5.0, 10.0, and 15.0 dSm(-1)). The fifteen barley genotypes showed statistically significant responses to different salinity levels. High values of CAT activity were found in Giza 123, line 2, Giza 137, Giza 131, Giza 136 and line 5 as tolerant genotypes under three salinity treatments. Similarly, high values of proline content were found in Giza 136 and Giza 123 seawater. Ten SRAP combination primers were used, the percentage of polymorphism for each primer combination varied from 33.3% (me2+em2) to 80.0% (me5+em6). The highest PIC was related to primer me5+em6 (0.89%), indicating that this primer is highly informative. The dendrogram of SRAP markers had clustered all the genotypes into two major clusters include the closest genotypes together. The results showed that there were high genetic differences among barley genotypes response for different seawater levels, which are useful for their utilization in further barley breeding programs for detections of salt tolerance.