Review on the Development of Drought Tolerant Maize Genotypes in Iraq

Abstract

Stress is any physiological, physical or chemical change that leads to disturbance and imbalance in the plant. Water stress is one of the most important environmental stresses affecting plant growth and production. It is also known as the lack of available water in the soil to be absorbed by the plant at a stage of its growth, or the inability of the plant. On the absorption of water even if it is naturally present in the root environment due to the force affecting the holding of water molecules, as it was described as the state in which the amount of water absorbed by the roots is less than the water lost through transpiration from the vegetative system, meaning that it is the state in which the effort The water content of the plant and the fullness of its cells is low to a degree that affects the conduct of vital and physiological processes. During the occurrence of water stress, as the term “drought” is not accurate in the sense used, but it is sometimes expressed as the phenomenon of water shortage as a result of climatic elements of multiple weather conditions, As for the agricultural concept of drought (Agricultural Drought), it is according to the growth and formation of the crop, and it is assumed that it begins when the ready water is drained from the root zone, plant goes through three stages: First stage increases the water loss and the transpiration process until it reaches a point where the amount of water lost by transpiration exceeds the amount of water absorbed by the roots. On the water balance between these two processes in adaptation, and when the water stress intensifies, the plant moves to the third stage, after which the plants lose a large part of the water through transpiration, the stomata are closed and the photosynthesis process stops. Therefore water stress (drought) alone is one of the most influential environmental stresses in reducing maize productivity, Therefore, the role of the plant breeder came through the implementation of breeding programs for hybridization and selection until it obtains a plant adapted to drought through the occurrence of morphological changes that make plants phenotypically adaptable to conditions of lack of water and includes an increase in root size and reduction of leaf area.

Biofortification of maize growth, productivity and quality using nano-silver, silicon and zinc particles with different irrigation intervals

“…Our findings also suggest that water stress significantly reduces maize grain yield by decreasing the number of rows per ear, and grain weight, and shortening the length of the grain filling period, which leads to the development of small and wrinkled grains. The use of AgNPs has been established as a plant growth stimulator in previous studies (Ogutu et 350 Essam E. Kandil et al 2019;Abdulhamed et al, 2021). Moreover, the current study indicates that the combined application of Zn, Si and AgNPs enhances the morphological and physiological characteristics of maize, particularly in alkaline calcareous soils where Zn deficiency is commonly found.…”

Mn3O4 Nanoparticles Alleviate ROS‐Inhibited Root Apex Mitosis Activities to Improve Maize Drought Tolerance

“…Under drought stress, the yield of maize was significantly reduced by 45%−60% compared with no stress condition, especially if it happens at the flowering period. [ 3 ]…”

“…Under drought stress, the yield of maize was significantly reduced by 45%−60% compared with no stress condition, especially if it happens at the flowering period. [3] Under drought stress, inhibition of plant cell mitosis activities was always observed. For example, drought inhibited maize leaf growth is associated with a significant reduction in cell number in the meristem.…”

Drought-Stress Effects on Resistant Gene Expression, Growth, and Yield Traits of Maize (Zea Mays L.)

“…The reason is that water resources play a vital role in determining optimum crop production and its sustainability. In Iraq, the present and prospective water situation necessitates effective management of water resources to maximize its utilization (Abdulhamed et al, 2021).…”