SALINITY STRESS Response of Wheat Varieties from Semi-arid Regions of Jordan to Salt Stress A. H. Abdel-Ghani Department of Plant Production, Faculty of Agriculture, Mu’tah University, Karak, Jordan Introduction Salinity is a global problem reducing plant growth and productivity worldwide, and affects about 7 % of the world’s total land area (Flowers et al. 1997). Some of the most severe problems in soil salinity are occurred in arid and semiarid regions of the world (Pesarraki 1999), where limited rainfall, high evapo-transpiration and high tem- perature play a very important role in increasing the salt concentration around the root zone. To solve the prob- lem of salinity, two strategies could be used: leaching salts from the soil profile by irrigation (Meri 1984, Al-Nabulsi 2001) and/or selecting more salt-tolerant genotypes (El-Hendawy et al. 2005; Jaradat et al. 2004). However, the cost and availability of irrigation water under semi- arid conditions make the irrigation approach not feasible for a large scale. Therefore, using the most salt-tolerant crop varieties will be the best viable avenue for increasing wheat productivity under saline conditions. Wheat is a moderately salt-tolerant crop (Maas and Hoffman 1977). Salt tolerance of wheat may vary with the growth stage (Kingsbury and Epstein 1984, El-Hendawy et al. 2005). Wheat is reported to be more salt tolerant at germination and during the flowering and Keywords germination; grain yield; salt stress; semi-arid conditions; wheat; yield components Correspondence Dr Adel H. Abdel-Ghani Department of Plant Production, Faculty of Agriculture, Mu’tah University, PO Box 7, Karak, Jordan Tel.: +962 799771229 Fax: +962 3 2323154 Email:abdelghani@mutah.edu.jo Accepted April 30, 2008 doi:10.1111/j.1439-037X.2008.00319.x Abstract This study was carried out to determine the effects of salinity levels (control, 6, 12 and 18 dS m )1 ) on germination, seedling growth, some agronomic traits and proline accumulation in leaves of nine wheat varieties adapted to semi-arid areas of Jordan. The tested wheat materials included eight durum wheat varie- ties (Haurani 27, Acsad 65, Om Rabbeeh, Sham 1, Safra Ma’an, Katma, Al-Samra and F8) and one bread wheat variety (Diel Harthon). Final germina- tion percentage, shoot and seminal root length, and all growth and yield parameters were significantly (P < 0.05) decreased by increasing salinity level. Proline content was significantly (P < 0.05) increased by increasing salinity. There were significant variety · salt interactions (P < 0.05) on final germina- tion percentage, seminal root length, grain yield and yield-related traits indicat- ing that the varieties responded to salt differently. Sham 1 did not show any decrease in germination ability at the different salinity levels. Haurani 27, Acsad 65, Al-Samra and Diel Harthon showed a nonsignificant reduction in germination potential at low and intermediate salt levels. Safra Ma’an and Al-Samra showed the lowest reduction in seminal root length at low salt level and consequently exhibited the lowest stress susceptibility index ‘S’ values. Grain yield-based stress susceptibility index ‘S’ indicated that Haurani 27, Acsad 65, Katma, Al-Samra, F8 and Diel Jardoon were more salt tolerant than Om Rabbeeh, Sham 1 and Safra Ma’an. In conclusion, a similar salt tolerance was observed at different growth stages in Haurani 27, Acsad 65 and Al-Samra. Consequently, these three varieties could be considered as salt tolerant and accordingly they are suitable for durum wheat improvement. Furthermore, Sham 1 had the highest ability to germinate at high salinity level indicating that it has a genetic potential for salt tolerance, at least at this stage of its life cycle. J. Agronomy & Crop Science (2009) ISSN 0931-2250 ª 2008 The Author Journal compilation ª 2008 Blackwell Verlag, 195 (2009) 55–65 55