Evaluation of sensitive and tolerant cultivars of barley to salt stress using tolerance indices in central regions of Iran

Undoubtedly, one of the biggest human challenges in the present age is food security, and salinity stress is one of the main obstacles to achieve this goal. In this regard, this experiment was conducted with the aim of selecting tolerance barley cultivar(s) to salinity stress and identifying tolerance mechanisms in new and old barley cultivars.

This experiment was carried out during the two years of 2016-17 in the Milshbar Ardakan region located in Yazd province. Experimental treatments included 9 six-rowed barley cultivars including Nik, Mehr, Khatam, Reyhan, Goharan, Nosrat, Morocco, Afzal and Fajr 30 cultivars in three levels of irrigation water salinity including 4, 10 and 14 dS/m were evaluated as a split plot experimental design so that water salinity as the main plots and cultivars as a sub-plots were randomly placed. The studied traits included yield and yield components. At the maturity stage, several plants were selected from each experimental plot and sodium and potassium were measured.

The results showed that salinity and cultivar treatment had a significant effect on the yield and yield components including number of seeds per spike, number of spikes per square meter and 1000-kernel weight. Salinity stress reduced grain yield components and among the studied cultivars, Nik, Mehr, Khatam and Reyhan cultivars had higher yield and yield components. Among the salinity treatments, the highest grain yield was obtained at 4 dS/m with 5770.64 kg/ha. With increasing salinity to 10 and 14 dS/m, grain yield decreased by 18.04 and 27.55%, respectively, and reached to 4729.29 and 41.8080 kg/ha. Among the studied cultivars, the highest grain yield was obtained in Nik with 5317.7 kg/ha and Mehr, Khatam and Reyhan were not significantly different with this cultivar. In salinity of 10 dS/m, the lowest grain yield variation were obtained in Goharan and Mehr cultivars and in salinity of 14 dS/m it was in Mehr and Afzal cultivars. The highest STI index in salinity of 10 compared to 4 dS/m was calculated in Nik and Mehr cultivars with 0.922 and 0.921, respectively. The highest value of this index in salinity 14 compared to 4 dS/m was also obtained in Nik and Khatam cultivars with 0.882 and 0.858, respectively.

Considering the amount of sodium and potassium absorbed by the plant and the K/Na ratio, it seems that tolerant cultivars cope with salinity stress by the mechanism of potassium uptake and excretion of sodium and regulation of cell osmotic potential. In general, among the studied cultivars, Nik, Mehr and Khatam cultivars had higher stress tolerance indices of STI, MP, Tol and these cultivars can be used for cultivation in saline lands of the region as well as for hybridization and breeding programs.