Responses of Barley (Hordeum vulgare L.) Genotypes to Salinity Stress Under Controlled and Field Conditions

This study was conducted to determine the effects of salinity on grain yield and some salinity-tolerance related traits of 20 barley genotypes in Bushehr province, Iran. Barley genotypes were selected on the basis of their tolerance to salinity in the temperate and warm regions or their yield performance and adaptability in the south warm regions of Iran. All 20 genotypes were initially evaluated for their salinity tolerance in greenhouse under pot culture and hydroponic conditions. Under both conditions, increasing salinity resulted in a significant decrease for all studied traits. The most salinity-tolerant genotypes under pot culture were genotypes STW-81-2, Golshan, Nimrooz and Oxin. In contrast, genotypes MBS-87-19, MBS-89-11, Zahak and ASBYT-M-86-3 exhibited higher salinity tolerance under solution culture. Based on results of greenhouse evaluation, seven lines and cultivars that showed higher tolerance to salinity were selected and studied in a field experiment under different salt treatments (1.5, 8 and 12 dS/m NaCl). Results of field experiment showed that cultivars Oxin and Nimrooz, and breeding line STW-81-10 which had high grain yield and outstanding salinity-tolerance related traits under pot culture, also performed well under salinity stress in the field experiment. Stress tolerance indices (STI) of genotypes Oxin, Nimrooz and breeding line STW-81-2 were 1.278, 1.068 and 0.960, respectively, indicating their higher salinity tolerance compared to the other genotypes. Results of this study indicated that barley genotypes with no history of selection for salinity tolerance (e.g Oxin and Nimrooz), but with a good level of adaptability in the warm climate zone, had better performance under saline conditions compared to those genotypes improved specifically for such conditions in the temperate zone of Iran. This finding may suggest that adaptation to climate conditions is an essential factor for breeding salinity tolerant barley genotypes in the warm zone of the country.