Response of six genotypes of wheat (Triticum aestivum L.) to water stress under field conditions.

Abstract

The 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 tolerate water stress in the vegetative and reproductive stages of six genotypes from Bread wheat (Triticum aestivum L.).This experiment was applied with The Randomized Complete Block Design (RCBD), split-plot arrangement, and three replications. The water stress treatments (S0) were set as the control treatment without stress and (S1) the stress treatment in the vegetative stage and (S2) treatment of stress in the , in the main plot, while the sub-plot included six genotypes of bread wheat, namely (Hawler 4, Abu Ghraib, Auras, Hewler 2, Nucal and S384).The water was blocked by covering the experimental units to prevent the arrival of rain, as well as cutting off irrigation in stages (between tillering and elongation).and (between flowering and filling the grains), the regular irrigation of the experimental units was conducted after depleting 50% of the available water in the soil, As for the water stress factors, they were left without irrigation for one irrigation and depletion of 75%-80% of the available water, and depending on the moisture description curve of the experimental soil. It was found from the study that the control treatment S0 excelled in the average number of spikes per m²and did not differ significantly from S2, as it was significantly excelled in the average grain yield, while the stress treatment S1 excelled in the weight of 1000 grains and the number of grains in the spike frome S2, and both of them did not differ significantly from the control treatment. The study concluded that the genotype (S384) excelled on the grain yield and gave 4.18 tons.ha^-1, followed by the genotype Nucal which gave 4.056 tons.ha-1.The genotype Nnucal recorded high values ​​for the average number of spikes, which amounted to 367.9 spikes.m^-2. It did not differ significantly from the genotype S384, which gave an average of 367.3 spikes.m^-2. The increase in the number of spikes had a great relationship with the high values of the tillers of the distinct genotypes, so it reached for the genotype Nucal 402.4 tillers .m^-2 and for the Auras genotype 400.2 tillers.m^-2,While the genotype S384 gave the highest value of 403.6 tillers.m^-2, the other yield components in the study were not affected by the distinct genotypes, with the exception of genotype S384, which was the highest in the average number of grains in the spike by 43.62 grains.spike^-