Physio-Morphological and Biochemical Trait-Based Evaluation of Ethiopian and Chinese Wheat Germplasm for Drought Tolerance at the Seedling Stage

Gizie Abeje Belay,Ping Xu,Zhengbin Zhang

doi:10.3390/su13094605

Abstract

For Ethiopia’s wheat production, drought is a major natural disaster. Exploration of drought-resistant varieties from a bulk of wheat germplasm conserved in the gene bank is of paramount importance for breeding climate change-resilient modern cultivars. The present study was aimed at identifying the best performing drought-resistant genotypes under non-stress and polyethylene glycol simulated (PEG) stress conditions in a growth chamber. Forty diverse Ethiopian bread and durum wheat cultivars along with three Chinese bread wheat cultivars possessing strong drought resistance and susceptibility were evaluated. After acclimation with the natural environment, the seedlings were imposed to severe drought stress (20% PEG6000), and 15 seedling traits including photosynthetic and free proline were investigated. Our findings indicated that drought stress caused a profound decline in plant water consumption (83.0%), shoot fresh weight (64.9%), stomatal conductance (61.6%), root dry weight (55.2%), and other investigated traits except root to shoot length ratio and proline content which showed a significant increase under drought stress. A significant and positive correlation was found between photosynthetic pigments in both growth conditions. Proline exhibited a negative correlation with most of the investigated traits except root to shoot length ratio and all photosynthetic pigments which showed a positive and non-significant association. Our result also showed a wide range of genetic variation (CV) ranging from 3.23% to 47.3%; the highest in shoot dry weight (SDW) (47.3%) followed by proline content (44.63%) and root dry weight (36.03%). Based on multivariate principal component biplot analysis and average sum of ranks (ASR), G12, G16 and G25 were identified as the best drought tolerant and G6, G42, G4, G11, and G9 as bottom five sensitive. The potential of these genotypes offers further investigation at a molecular and cellular level to identify the novel gene associated with the stress response.

Highlights

Physiological processes such as plant water consumption (PWC), relative water content (RWC), stomatal conductance, transpiration rate and canopy temperature are the key determinant of plant water relations
Severe drought stress imposed at the early growth stage significantly affected the growth and physio-biochemical traits of wheat seedlings
Among morphophysiological and biochemical traits, plant water consumption (PWC) was highly affected by drought stress followed by stomatal conductance and shoot fresh weight (SFW)

Summary

Introduction

Wheat (Triticum L.) is one of the most important domesticated cereal crops in the fertile crescent between 8000 and 10,000 years [1]. Wheat ranks second after rice in terms of production; provides 55% carbohydrates, 20% proteins, and calories for the daily requirements of 4.5 billion people [2,3,4]. China is the largest wheat producer and consumer in the world [5]; drought stress is a major factor threatening wheat productivity in the major growing areas such as North China plains.

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