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

Document Type: Research Paper

Authors

1 Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz Iran.

2 Dep of Agronomy and Plant Breeding, Shiraz University

3 Associate Professor, Seed and Plant Improvement Research Department, Yazd Agricultural and Natural Resources and Education Center, AREEO, Yazd , Iran.

4 Department of Water Engineering, College of Agriculture, Shiraz University, Shiraz, Iran.

Abstract

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

Keywords