Evaluation of Salinity Tolerance Threshold of Selected Pomegranate Genotypes

In order to determine salinity tolerance threshold and yield decrease per unit increase of soil salinity in selected pomegranate genotypes, a factorial experiment was carried out based on completely randomized design (CRD), with two factors: genotypes in 12 types (Shisheh Kap Ferdus, Malas Yazdi, Malas Saveh, Rabab Neyriz, Golnar Saveh, Golnar Sarvestan, Golnar Shahdad, Narak Lasjerd Semnan, Vahshi Babolsar, Post Siyah Ardakan, Chah Afzal and Voshik Torsh Saravan) and soil salinity at five levels (1.5, 3.8, 6.2, 9.3 and 12.6 dSm-1). According to the results, the lowest salinity tolerance threshold was observed in Voshik Torsh Saravan (3.02 dS/m), Malas Saveh (3.25 dS/m) and Golnar Saveh (3.40 dS/m) genotypes, and the highest salinity tolerance threshold was observed in Golnar Shahdad (4.90 dS/m), Chah Afzal (4.70 dS/m), Post Siyah Ardakan (4.38 dS/m), and Malas Yazdi (4.17 dS/m) genotypes. The highest yield reduction slope was observed in Golnar Saveh (7.89%), Golnar Sarvestan (7.39%), Voshik Torsh Saravan (6.69%), and Malas Saveh (6.33%) genotypes, respectively. In contrast, the lowest yield reduction slope was observed in Chah Afzal (2.83%), Post Siyah Ardakan (2.88%) and Narak Lasjerd Semnan (2.89%) genotypes, respectively. Overall, the results showed the levels of salinity that reduced the yield by 50% in Chah Afzal, Post Siyah Ardakan and Narak Lasjerd Semnan genotypes were about twice greater than salinity that reduced the yield by 50% in Golnar Saveh, Golnar Sarvestan, Voshik Torsh Saravan and Malas Saveh genotypes. EC50 in Chah Afzal, Post Siyah Ardakan, and Narak Lasjerd Semnan genotypes were observed at 22.37, 21.74 and 21.10 dS/m. At salinity level of 8.4 dS/m, yield reductions in Chah Afzal, Post Siyah Ardakan and Narak Lasjerd Semnan genotypes were only 10.47%, 11.58%, and 13.30%, respectively, which were lower than the 50% value previously reported. Therefore, these three genotypes were selected for further studies and planting as rootstocks in Chah Afzal Station of National Salinity Research Center.