Assessment of the salt tolerance of wheat genotypes during the germination stage based on germination ability parameters and associated SSR markers

Salah El-Hendawy,Adel Elshafei,Nasser Al-Suhaibani,Majed Alotabi,Wael Hassan,Yaser Hassan Dewir,Kamel Abdella

doi:10.1080/17429145.2019.1603406

Abstract

ABSTRACT Although the germination stage accounts for a very short period of a plant’s life cycle, it involves numerous mechanisms and multistage processes that potentially differ among genotypes under salt stress. Therefore, we hypothesized that the parameters controlling the water uptake pattern and α-amylase activity during the seed germination process could be helpful for assessment the salt tolerance of wheat genotypes at the early growth stage. Genotypic differences in the germination ability parameters and α-amylase activity were assessed for seven wheat cultivars under normal and salt stress conditions at the molecular marker level using 30 simple sequence repeat (SSR) markers linked to salt tolerance. Results found that genotypic variations in the water uptake pattern were appeared at the late stage of phase II under both salinity levels and more obviously during phase III. Genotypic variations were observed in the germination time (GT), which was delayed by increasing salinity levels. The α-amylase activity and GT were positively and negatively correlated, respectively, with each time of water uptake rate. Significant correlation (r = 0.49, P = 0.026) was observed between similarity coefficients of germination ability parameters and SSR data based on the Mantel test. Among the 24 SSR markers, which showed polymorphism, Cdf 9, Cdf 46, Cdf 49, Wmc 503, and Gwm 312 were associated with almost germination ability parameters (R 2 ranged from 0.43 to 0.95). Therefore, based on the molecular marker-phenotypic trait association at germination stage, assessment of salt tolerance in many wheat genotypes in a relatively short time could be conceivable.

Highlights

Seed germination is one of the most critical stages in the plant life cycle, as it directly determines the failure or success of the subsequent growth stages (Saritha and Prasad, 2007; El-Hendawy et al 2011; Liu et al 2018)
The study verified that the delaying of the germination time under salt stress was not the result of a reduction in water uptake, which was confirmed by the germination percentage reaching 100% even under high salinity levels
It is related to the water uptake regulation and α-amylase activity during the seed germination process

Summary

Introduction

Seed germination is one of the most critical stages in the plant life cycle, as it directly determines the failure or success of the subsequent growth stages (Saritha and Prasad, 2007; El-Hendawy et al 2011; Liu et al 2018). Phase I represents fast water uptake by the dry seed This is followed by a plateau phase (phase II, metabolism reactivation), which is characterized by the limited water uptake. Comes phase III, a post-germination phase of water uptake, which is characterized by continuous water uptake until germination is complete Based on these three phases, the inhibition of seed germination under salinity stress could be generally attributed to osmotic stress in the phase I and ionic stress in the phase II. To decrease the negative effects of salinity stress on seed germination, it is important to know to what extent the genotypic variation in the water uptake pattern during these phases is associated with the salt tolerance of genotypes at the germination stage

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Discussion

Conclusion