Evaluation of the Tolerance Ability of Wheat Genotypes to Drought Stress: Dissection through Culm-Reserves Contribution and Grain Filling Physiology

Md Amirul Islam,Eldessoky S Dessoky,Akbar Hossain,Md Abdul Kader,Md Sabibul Haque,Md Solaiman Ali Fakir,Md Nesar Uddin,Md Alamgir Hossain,Rajib Kumar De,Attia O Attia,Ehab I El-Hallous

doi:10.3390/agronomy11061252

Abstract

Drought stress is one of the limiting factors for grain filling and yield in wheat. The grain filling and determinants of individual grain weight depend on current assimilation and extent of remobilization of culm reserves to grains. A pot experiment was conducted with eight wheat cultivars at the Pot House to study the grain filling and the contributions of reserves in culm, including the sheath to grain yield under drought stress. Drought stress was enforced by restricting irrigation during the grain-filling period. The plants (tillers) were harvested at anthesis, milk-ripe, and maturity. The changes in dry weights of leaves, culm with sheath, spikes, and grains; and the contribution of culm reserves to grain yield were determined. Results revealed that drought stress considerably decreased the grain filling duration by 15–24% and grain yield by 11–34%. Further, drought-induced early leaf senescence and reduced total dry matter production indicate the minimum contribution of current assimilation to grain yield. The stress reduced the contribution of culm reserves, the water-soluble carbohydrates (WSCs), to the grains. The accumulation of culm WSCs reached peak at milk ripe stage in control, varied from 28.6 to 84 mg culm−1 and that significantly reduced in the range from 14.9 to 40.6 mg culm−1 in stressed plants. The residual culm WSCs in control and stressed plants varied from 1.23 to 8.12 and 1.00 to 3.40 mg g−1 culm dry mass, respectively. BARI Gom 24 exhibited a higher contribution of culm WSCs to grain yield under drought, while the lowest contribution was found in Kanchan. Considering culm reserves WSCs and their remobilization along with other studied traits, BARI Gom 24 showed greater drought tolerance and revealed potential to grow under water deficit conditions in comparison to other cultivars.

Highlights

Drought is one of the major abiotic stresses affecting the productivity of crops worldwide
The effect of drought stress during the grain-filling period on grain yield, biomass yield, harvest index, and yield components of eight wheat cultivars is presented in Table 1 and Figure 2
Wheat cultivars used in this study showed significant variations in grain yield and yield contributing parameters (Table 1)

Summary

Introduction

Drought is one of the major abiotic stresses affecting the productivity of crops worldwide. It impairs plant productivity by inhibiting growth and development [1] Drought reduces morpho-physiological traits such as leaf sizes, photosynthesis rate, stomatal conductance, and alters the plant’s anatomical features [2]. Drought hampers wheat growth at the seedling stage [4], water scarcity at the grain development stage reduces grain yields drastically [5,6]. The grain development is the most critical growth phase in wheat under water deficit condition, and drought mediated impairment in the rate and duration of grain filling determines the size of the grains and causes 31–92% yield reduction [7].

Methods

Discussion

Conclusion