Response of six genotypes of bread wheat (Triticum aestivum L.) to water stress under conditions of the central region of Iraq.

Abstract

A field study was conducted at Al-Muradia Research Station, located southwest of the center of Babylon province, at latitude 30 32 North and longitude 39 44 East during the winter season 2019-2020 in a sedimentary soil with a silty loam texture to study the ability to withstand water stress in the vegetative and reproductive stages of six genotypes from Bread wheat (Triticum aestivum L.).This experiment was conducted with The Randomized Complete Block Design (RCBD), split-plot arrangement, and three replications. treatments (S1) control treatment without stress and (S2) the stress treatment in the vegetative stage and (S3) the stress treatment in the reproductive stage in the main plots , while the subplots included six genotypes of bread wheat, namely (Hawler 4, Abu Ghraib, Auras, Hewler 2, Nucal and SST843),The water was blocked by covering the experimental units to prevent the arrival of rain, as well as cutting off irrigation in the stages (between tillering and elongation) and (between flowering and grain filling),Regular irrigation of the experimental units was applied after depleting 50% of the available water in the soil, while the water stress factors were left without irrigation for one irrigation and depletion of 80%-75% of available water and depending on the moisture description curve of the experimental soil. It was found from the study that the genotypes affected by water stress in a different method from one genotype to another and that the best genotypes tolerant to water stress were the two genotypes SST843 and Nucal by giving them the lowest decrease in grain yield with an average of (4.18, 4.06) tons ha^-1respectively and the amount of decrease in this trait (grain yield) under the influence of stress in the reproductive phase is more than the vegetative stage, and these two structures were distinguished in the rest of the studied traits, such as the relative water content in which the Nucal genotype gave the highest average for the trait amounting to 91%. The proline content in which the SST843 genotype gave the highest average was 141.8 μg, and the two genotypes Nucal and SST843 gave the highest average total peroxide content of the flag leaf amounting to (1.59,1.69) μg, respectively and the highest average content of total soluble sugars in the flag leaf was (42.12,40.40) mg respectively