Rising Atmospheric Temperature Impact on Wheat and Thermotolerance Strategies

Abstract

Temperature across the globe is increasing continuously at the rate of 0.15–0.17 °C per decade since the industrial revolution. It is influencing agricultural crop productivity. Therefore, thermotolerance strategies are needed to have sustainability in crop yield under higher temperature. However, improving thermotolerance in the crop is a challenging task for crop scientists. Therefore, this review work was conducted with the aim of providing information on the wheat response in three research areas, i.e., physiology, breeding, and advances in genetics, which could assist the researchers in improving thermotolerance. The optimum temperature for wheat growth at the heading, anthesis, and grain filling duration is 16 ± 2.3 °C, 23 ± 1.75 °C, and 26 ± 1.53 °C, respectively. The high temperature adversely influences the crop phenology, growth, and development. The pre-anthesis high temperature retards the pollen viability, seed formation, and embryo development. The post-anthesis high temperature declines the starch granules accumulation, stem reserve carbohydrates, and translocation of photosynthates into grains. A high temperature above 40 °C inhibits the photosynthesis by damaging the photosystem-II, electron transport chain, and photosystem-I. Our review work highlighted that genotypes which can maintain a higher accumulation of proline, glycine betaine, expression of heat shock proteins, stay green and antioxidant enzymes activity viz., catalase, peroxidase, super oxide dismutase, and glutathione reductase can tolerate high temperature efficiently through sustaining cellular physiology. Similarly, the pre-anthesis acclimation with heat treatment, inorganic fertilizer such as nitrogen, potassium nitrate and potassium chloride, mulches with rice husk, early sowing, presoaking of a 6.6 mM solution of thiourea, foliar application of 50 ppm dithiothreitol, 10 mg per kg of silicon at heading and zinc ameliorate the crop against the high temperature. Finally, it has been suggested that modern genomics and omics techniques should be used to develop thermotolerance in wheat.

Nitric Oxide and Abscisic Acid Mediate Heat Stress Tolerance through Regulation of Osmolytes and Antioxidants to Protect Photosynthesis and Growth in Wheat Plants

“…It was found that ABA enhanced sugar accumulation under saline conditions [ 115 ] and ABA and sucrose increased the survival rate of bromegrass cells under heat stress [ 116 ]. It has been reported that genotypes that maintain a higher accumulation of proline, GB, and expression of heat shock proteins, together with activity of antioxidant enzymes such as catalase, peroxidase, SOD, and GR, can tolerate high temperature efficiently through sustaining cellular physiology [ 117 ]. Nitric oxide also influences soluble sugar accumulation under heat stress.…”

Heat stress effects on the reproductive physiology and yield of wheat

“…In wheat, heat stress before or during anthesis reduces seed set due to (i) the formation of non-viable pollen or ovules, (ii) restricted growth of pollen tube or (iii) inability of fertilized embryo sacs to transition to seed (Khan et al, 2021;Saini et al, 1983Saini et al, , 1984. Moreover, heat stress causes embryo abortion in wheat as ethylene production increases, reducing kernel weight (Hays et al, 2007;Zahra et al, 2021).…”

Multiple Antioxidative and Bioactive Molecules of Oats (Avena sativa L.) in Human Health

“…Although there are differences in the level of nutrients between each grain, these grains are rich in protein, vitamins, minerals, and dietary fiber compared to the commonly consumed rice (white rice), barley, and wheat. Functional grains help the modern population suffering from “poverty in the midst of plenty” due to busy daily life, irregular meals, and frequent consumption of take-out restaurant meals to ingest abundant nutrients [ 3 , 4 , 5 , 6 , 7 , 8 ].…”