Evaluation of Fourteen Bread Wheat (Triticum aestivum L.) Genotypes by Observing Gas Exchange Parameters, Relative Water and Chlorophyll Content, and Yield Attributes under Drought Stress

Abstract

Water scarceness is a major threat to wheat productivity under changing climate scenarios, especially in arid and semi-arid regions. However, growing drought-tolerant wheat genotypes could be a sustainable option to enhance wheat productivity under drought stress conditions. The aim of this study was to evaluate the effect of mild to severe drought stress on gas exchange parameters, relative water content, SPAD-chlorophyll value, and yield-related parameters of 14 wheat genotypes being cultivated in arid to semi-arid areas on large scale. The genotypes were grown in earthen pots under three drought levels, namely (1) control-well watered, (2) mild water stress, i.e., 60% water holding capacity, and (3) severe water stress, i.e., 40% water holding capacity. The drought was imposed from the jointing stage to physiological maturity. Drought significantly decreased net photosynthesis, stomatal conductance, relative water contents, 100-grain weight, and grain yield in all genotypes. However, the reduction percentage was different in different genotypes under drought stress compared with well-watered conditions. The highest relative water content (65.2%) was maintained by the genotype Galaxy-2013, followed by AAS-2011 (64.6%) and Johar-2016 (62.3%) under severe drought conditions. Likewise, Galaxy-2013 showed the highest net photosynthesis and stomatal conductance under severe drought conditions. The highest grain yield per plant (6.2 g) and 100-grain weight (3.3 g) was also recorded in Galaxy-2013 under severe drought conditions, while the highest grain yield under well-watered conditions was recorded in Johar-2016, followed by Galaxy-2013. These results suggest that wheat variety Galaxy-2013 could be cultivated extensively to obtain good wheat yield under limited water conditions.

Evaluation of Drought Tolerance of Some Wheat (Triticum aestivum L.) Genotypes through Phenology, Growth, and Physiological Indices

“…Hence, it is indicated that the wheat grains of BAW 1167, BARI Gom 26, and BAW 1158 dried quickly and attained physiological maturity earlier as compared to BAW 1169. The sigmoid way involving accumulation of dry matter under DS has also been reported earlier [69,89]. The DS condition leads to reduced plant growth, which is reflected in plant height, leaf area, dry weight, and other growth functions [42,90], reduced Chl content, photosynthetic rate, and TDM [14,39,91].…”

“…The results indicated that genotypes BAW 1169 and BAW 1158 were relatively less affected by water deficit stress than the other two genotypes. DS leads to reduced plant growth reflected in leaf area, dry weight, spike length, number of grains spige −1 and grain weight [39,42,89,90]. High Chl content under DS indicates lower intensity of photosynthetic apparatus's photo-inhibition, therefore decreasing losses of carbohydrates for grains development [95].…”

Higher Photochemical Quenching and Better Maintenance of Carbon Dioxide Fixation Are Key Traits for Phosphorus Use Efficiency in the Wheat Breeding Line, RAC875

“…For example, a recent study in wheat showed a positive correlation between grain yield and photosynthetic rate at the heading and grain filling stage (Yu et al, 2020). A similar result in wheat grown under well-watered conditions was also reported by Wasaya et al (2021).…”

Effect of Salinity Stress on Physiological Changes in Winter and Spring Wheat

“…For example, the high concentrations of salt in saline habitats Agronomy 2021, 11, 1193 2 of 16 make it difficult for roots to absorb water from the soil. Drought reduces morphological traits such as the reduction of leaf size and vegetative growth, and physiological traits such as the reduction of photosynthesis and stomatal conductance, and alters the anatomical characteristic of the stem [1,2].The results of these stresses induce an excessive production of reactive oxygen species (ROS), which cause extensive cell damage and inhibition of photosynthesis [3,4]. To these stresses are added the deficits of inorganic nutrients, the residues of chemicals such as herbicides and pesticides used in normal agricultural practice and heavy metals present in the earth's crust that emanate from industrial activities [5][6][7][8].…”