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

Abstract

Selecting and cultivating the crops/varieties that can tolerate water salinity is potentially animportant strategy to save fresh water resources and maximize the crop yield in salt affected areas.To evaluate the responses of 36 sorghum lines and cultivars to salinity stress, two fieldexperiments were conducted in non-stress (EC=2 dS/m) and salinity stress conditions (EC=12dS/m) using randomized complete block design with three replications. The field experimentswere carried out at research station of Agricultural Research Center and Natural Resources ofYazd, Iran in 2014 and 2015 growing seasons. Under salinity stress conditions, grains/panicle,panicle length, 1000 grain weight, grain yield, biological yield and harvest index were decreased36%, 15%, 42%, 64%, 40% and 39%, respectively. The highest grain yield under non-stressconditions was produced by KDFGS2 (8182.6 kg/ha) while the highest grain yield under salinitystress conditions was achieved by KDFGS6 (3310 kg/ha). Correlation coefficients between grainyield (for both conditions) and tolerance indices showed that geometric mean productivity (GMP),stress tolerance index (STI) and harmonic mean (HAM) indices were appropriate for screeninghigh-yielding genotypes. Principal component analysis validated the results of screening methodsand introduced lines number 1, 7 and 9 as superior genotypes under both conditions. Lines number2, 8, 15, 19, 29 and cultivars Ghalami-Herat, Sepideh and Kimia showed greater sensitivity tosalinity stress. Since lines number 4, 6, 10 and 24 had greater yield stability, it appears that theymay worth further explorations in future breeding projects.