Water Deficit Stress Tolerance Potential of Newly Developed Wheat Genotypes for Better Yield Based on Agronomic Traits and Stress Tolerance Indices: Physio-Biochemical Responses, Lipid Peroxidation and Antioxidative Defense Mechanism

Abstract

Changing environmental conditions, fresh water shortages for irrigation and the rapid increase in world population have created the problems of food insecurity and malnutrition. Different strategies, including the development of water stress-tolerant, high-yielding genotypes through breeding are used to fulfil the world food demand. The present study was conducted for the selection of high-yielding, drought-tolerant wheat genotypes, considering different morpho-physio-biochemical, agronomic and yield attributes in relation to the stress tolerance indices (STI). The experiment was carried out in field in a split-plot arrangement. Water deficit stress was maintained based on the number of irrigations. All genotypes showed a differential decreasing trend in different agronomic traits. However, the increasing or decreasing trend in leaf photosynthetic pigments, non-enzymatic and enzymatic antioxidants under limited water supply also found to be genotype-specific. Genotypes MP1, MP3, MP5, MP8 and MP10 performed better regarding the yield performance under water deficit stress, which was associated with their better maintenance of water relations, photosynthetic pigments and antioxidative defense mechanisms. In conclusion, the physio-biochemical mechanisms should also be considered as the part of breeding programs for the selection of stress-tolerant genotypes, along with agronomic traits, in wheat.

Keywords: agronomic traits; breeding; oxidative stress; photosynthetic pigments; water relations; water stress; yield.

Figure 1

(A) Leaf hydrogen peroxide (H₂O₂), (B) superoxide dismutase (SOD), (C) activities of catalase (CAT), (D) ascorbate peroxidase (APX), (E) peroxidase (POD), (F) content of malondialdehyde (MDA) and (G) leaf relative membrane permeability (LRMP) of the newly developed inbreed wheat genotypes under limited water supply and normal irrigation (Mean ± SE; n = 4). (Bars against a wheat genotype with * shows significance effect of water deficit stress).

Figure 2

Leaf total phenolic contents (TPC), flavonoids and ascorbic acid (AsA), of newly developed inbreed wheat genotypes when grown under limited water supply and normal irrigation (Mean ± SE; n = 4). (Bars against a wheat genotype with * shows significance effect of water deficit stress).

Figure 3

Total soluble sugars (TSS), non-reducing sugars (NRS), reducing sugars (RS), leaf-free amino acids (FAA), total soluble proteins (TSP), and anthocyanin contents of newly developed inbreed wheat genotypes under limited water supply and normal irrigation (Mean ± SE; n = 4). (Bars against a wheat genotype with * shows significance effect of water deficit stress.).

Figure 4

Principal component analyses (PCA) for different growth, biochemical and physiological attributes of newly developed wheat genotypes under limited water supply and normal irrigation.