Assessment of agro-physiological traits for salt tolerance in drought-tolerant wheat genotypes

Document Type: Research Paper

Authors

1 Department of Crop Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. bDepartment of Molecular Physiology, Agricultural Biotechnology Research Institute of Iran (ABRII), Karaj, 31535-1897, Iran.

2 Department of Crop Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.

3 Department of Molecular Physiology, Agricultural Biotechnology Research Institute of Iran (ABRII), Karaj, 31535-1897, Iran.

Abstract

Salt stress is one of the major constraints for wheat cultivation inIranand leads to
a considerable loss in crop yield each year. In high salinity soils, the reduced osmotic
potential of soil solutes may cause physiological drought. In this study the salt
tolerance of different drought-tolerant bread wheat genotypes were studied by
examining various agronomic and physiological traits, including Na+ and K+
concentrations, the Na+/K+ ratio in leaf and spike, shoot dry weight, leaf greenness,
stomatal conductance, leaf area, osmotic potential, relative water content (RWC) and
grain yield. Two pot experiments were conducted using a completely randomized
design with three replications. Wheat genotypes were grown in pots and irrigated
either with tap water (EC=0.5 dSm-1) or saline water (EC≈18 dsm-1) as control and
salt stress treatments, respectively. Significant differences were observed in all
measured traits between control and stress treatments except for the spike potassium
concentration. Differences between genotypes were significant for all traits except
for RWC and osmotic potential. Among the different genotypes, one drought-tolerant
genotype appeared salt tolerant, three were semi-salt-tolerant, one drought-sensitive
genotype appeared semi-salt-sensitive, and two drought-tolerant genotypes appeared
salt-sensitive and semi-salt-sensitive. This study shows that drought tolerance does
not necessarily lead to salt tolerance. Some physiological traits including Na+
content, leaf area, SPAD number, stomatal conductance and shoot dry weight, which
are significantly correlated with grain yield and show remarkable variations among
wheat genotypes, may be useful parameters for measuring the responses of other
wheat genotypes to high-salinity soils in the field.

Keywords