Database Research Summaries2018 Evaluation of Soybean Tolerance to Salinity, Alkalinity and the Combined Saline-Alkalinity
Research Focus
The focus of this project is to evaluate common pre-emergent herbicide options that would be used in cases of glyphosate resistance under different environmental circumstances.
Objectives
- Develop methods used for screening soybean tolerance to salinity, alkalinity, and saline-alkalinity.
- Evaluate the tolerance of 50 soybean genotypes to the aforementioned three stresses.
Results
- 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.
Importance
- 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.
For more information about this research project, please visit the National Soybean Checkoff Research Database.
Funded in part by the soybean checkoff.
