Project Details:

Evaluation of Soybean Tolerance to Salinity, Alkalinity and the Combined Saline-Alkalinity

Parent Project: This is the first year of this project.
Checkoff Organization:North Dakota Soybean Council
Categories:Environmental stress
Organization Project Code:QSSB
Project Year:2018
Lead Principal Investigator:Qi Zhang (North Dakota State University)
Co-Principal Investigators:

Contributing Organizations

Funding Institutions

Information and Results

Comprehensive project details are posted online for three-years only, and final reports indefinitely. For more information on this project please contact this state soybean organization.

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Final Project Results

Updated January 3, 2019:
Please see the attached file

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High soil salinity is a common problem in North Dakota, resulting in reduced growth/yield or even death under the severe condition. Previous research on screening salt-tolerant plants was mainly conducted using chloride salts (e.g., NaCl). In North Dakota, the predominant forms of salinity are sulfate salts (mostly Na2SO4 and MgSO4), while chloride-salinity is only seen in the eastern Grand Forks. Information on soybean responses to sulfate-salinity is scarce. Iron-deficiency chlorosis (IDC) is commonly seen in the high pH soil (pH > 7) (i.e. alkalinity) in North Dakota. Research on soybean tolerance to IDC has been well documented. However, a fast and reliable screening method for alkalinity tolerance needs to be developed for genotype evaluation. Salinity and alkalinity often coexist in nature. Limited information is available on soybean responses to the combined saline-alkalinity stress.

We conducted this project to develop screening methods for soybean tolerance to sulfate-salinity, alkalinity, and saline-alkalinity and identify genotypes with high tolerance to the aforementioned stresses.

Our results showed that NaCl was more detrimental to soybean plants, causing severe damage at 4 dS m-1 and plant death at 8 dS m-1 after three weeks of saline exposure. Plants survived at 16 dS m-1 under sulfate-salinity (a Na2SO4 +MgSO4 mixture) and growth inhabitation did not occurred until 8 dS m-1. Alkalinity (pH = 7.3 – 9.4) also reduced soybean growth. Tissue biomass was reduced at pH of 7.3, lower than that for leaf chlorosis to be detected (= 8.8). The combined stress caused higher growth reduction compared to salinity and alkalinity alone. All stresses caused increased Na but decreased K and Ca uptake in shoot. Alkalinity and saline-alkalinity also affected Fe, Mn, and Zn absorption.

Fifty genotypes, including 9 glyphosate-resistant and 41 non-resistant ones, were evaluated for the tolerance to salinity (Na2SO4+MgSO4 at 8 dS m-1), alkalinity (pH = ~9.0), and the combined saline-alkalinity. Genetic differences were detected mostly in shoot and root dry weight and leaf size, but not in leaf chlorosis. Genotypes with high tolerance to salinity and/or alkalinity did not all perform well under the combined stress.

Soybean breeders can use our protocols to screen for high tolerance to salinity, alkalinity, and saline-alkalinity and incorporate the plant materials identified in this research into different breeding purposes. Our research also expands growers’ knowledge on the effects of salinity (salt type and concentration), alkalinity, and their interaction on soybean growth.

Project Years