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

Abstract

<span class="fontstyle0">Selecting and cultivating the crops/varieties that can tolerate water salinity is potentially an<br />important strategy to save fresh water resources and maximize the crop yield in salt affected areas.<br />To evaluate the responses of 36 sorghum lines and cultivars to salinity stress, two field<br />experiments were conducted in non-stress (EC=2 dS/m) and salinity stress conditions (EC=12<br />dS/m) using randomized complete block design with three replications. The field experiments<br />were carried out at research station of Agricultural Research Center and Natural Resources of<br />Yazd, Iran in 2014 and 2015 growing seasons. Under salinity stress conditions, grains/panicle,<br />panicle length, 1000 grain weight, grain yield, biological yield and harvest index were decreased<br />36%, 15%, 42%, 64%, 40% and 39%, respectively. The highest grain yield under non-stress<br />conditions was produced by KDFGS2 (8182.6 kg/ha) while the highest grain yield under salinity<br />stress conditions was achieved by KDFGS6 (3310 kg/ha). Correlation coefficients between grain<br />yield (for both conditions) and tolerance indices showed that geometric mean productivity (GMP),<br />stress tolerance index (STI) and harmonic mean (HAM) indices were appropriate for screening<br />high-yielding genotypes. Principal component analysis validated the results of screening methods<br />and introduced lines number 1, 7 and 9 as superior genotypes under both conditions. Lines number<br />2, 8, 15, 19, 29 and cultivars Ghalami-Herat, Sepideh and Kimia showed greater sensitivity to<br />salinity stress. Since lines number 4, 6, 10 and 24 had greater yield stability, it appears that they<br />may worth further explorations in future breeding projects.</span>