A review on the effect of heat stress in wheat (Triticum aestivum L.)

Abstract

Wheat is one of the most important cereal crops in the world. It ranks first (in the world) and third (in Nepal) in terms of productivity and total cropped area. Worldwide, wheat provides nearly 55% of the carbohydrates and 20% of the food calories. The ideal temperature for its cultivation is about 15°-20°C. Among several abiotic factors, heat stress is one of the major factors affecting wheat production. Wheat is very sensitive to heat stress. Each degree rise in the temperature can decrease wheat yield by 6%. This review is written with an aim to reflect the influence of heat stress in the production of wheat and the mechanism of how loss in yield occurs. Some of the major findings of this research are : (a) Heat stress negatively effects germination, emergence, root growth, leaf, stem development and growth, tillering, grain yield and quality (b) A sharp decline in photosynthesis is evident when wheat plant is exposed to high temperature stress during vegetative or reproductive phase (c) With increases in temperature, rate of respiration is greater  than the rate of photosynthesis  which ultimately leads to carbon starvation (d) High temperature fastens the crop growth by making it to enter into jointing stage and reproductive stage earlier than normal resulting in decreased crop yield. The identification of such effects of heat stress in our crop helps us adopt several strategies or methods to mitigate the impacts on crop yields and improve tolerance to heat stress.