Bread Wheat (Triticum aestivum L.) Under Biotic and Abiotic Stresses: An Overview

Abstract

Wheat, a major cereal crop, is subject to several biotic and abiotic stresses. These stresses affect the crop’s yield globally. Different mechanisms have been adopted by plants to counter the wide range of biotic and abiotic stresses faced. The scarcity of irrigation water leads to moisture stress in the wheat crop. The quantitative trait loci tool is used to map the moisture-tolerant inherited genes. Genes that are drought tolerant have been identified in other crops and scientists are planning to introduce them into the wheat genomes. Similarly, understanding the heat stress tolerance pathway is underway. Moreover, cryoprotectant genes that code for proteins which help the plants gain tolerance to severe cold can be transformed into commercial wheat varieties to tackle cold stress. Several genetic engineering techniques are being developed to minimize micronutrient and waterlogging stress. Biotic stresses include parasitic and nonparasitic diseases. In order to ward these off, plants use systemic acquired resistance and induced systemic resistance, but these are not sufficient when stress reaches its extreme. Seedborne diseases result in lightweight shriveled kernels resulting in an overall reduction in the crop yield. There is also a range of pathogenic fungi and viruses that cause various leaf and root diseases in wheat. Disease control strategies are underway to limit the damage to the wheat crop. Furthermore, soil moisture level, the depth of seed plantation, PH control for fungal growth reduction, and use of certain antibiotics in the soil can greatly reduce the risk of biotic stress-related wheat diseases. In addition to all of these aspects, pivotal to maximize wheat productivity is genetic improvement where harnessing and exploiting smartly via state-of-the-art technologies pointing towards genetic resource diversity is paramount as a means for providing high levels of allelic variation around all major stress constraints.