Evaluation of Sorghum (Sorghum bicolor L.) lines and cultivars under salinity stress using tolerance indices

To evaluate the response of 45 sorghum lines and cultivars to salinity stress, two experiments were conducted in non-stress (EC=2 dS.m-1) and salinity stress conditions (EC=12 dS.m-1) using randomized complete block design with three replications. The experiments were carried out at Ardakan research station of Agricultural and Natural Resources Research Center of Yazd, Iran, in 2014. Salinity stress significantly decreased all measured traits in lines and genotypes. Under salinity stress conditions, stem diameter, stem height, leaf number, leaf area index, fresh forage yield and dry forage yield were decreased 14.45%, 25.24%, 18.06%, 31.86%, 40.19% and 32.36%, respectively. The highest dry forage yield under non-stress and salinity stress conditions was produced by KDFGS23 (28530 kg.ha-1) and Jumbo cultivar (21042 kg.ha-1), respectively. Results of correlation coefficients among dry forage yield under non-stress and stress conditions and tolerance indices showed that GMP, HAM, MP and STI indices were the most suitable tolerance indices. Results of cluster analysis showed that Jumbo, Pegah, Sistan, Sweet sorghum, Ghalami Herat and Speedfeed (Moghan) had higher tolerance to salinity stress, while lines KDFGS23 and KDFGS26 and Nectar cultivar had greater sensitivity to salinity stress. Since line No. 1 (KDFGS1) had greater yield stability, it worth further explorations in future breeding projects.