Document Type : Research Paper

Authors

• Aylar Saadat sattarzadeh ¹
• Hossein Shahbazi ²
• Varahram Rashidi ¹
• Alireza Ahmadzadeh ¹
• farhad farahvash ³

¹ Department of Agronomy and Plant Breeding, Tabriz Branch, Islamic Azad University, Tabriz, IRAN

² Department of plant breeding, Ardabil Branch,Islamic Azad University, Ardabil, Iran.

³ faculty in azad univercity

Abstract

Introduction: The root system architecture is one of the basic characteristics of barley cultivars in drought stress tolerance. So that the genotypes with more vertical roots will have more tolerance to drought. Therefore, root growth angle is a suitable trait to improve drought tolerance in barley. For this purpose, to investigate the effect of HvDRO1 gene expression on root system architecture of barley cultivars under water stress, an experiment was conducted using glass rhizotrons.
Materials & Methods: The experiment was conducted as a factorial design, in which the first factor included 10 barley cultivars and the second factor included drought stress (nonstress, 75% FC and 50% FC). The experiment was carried out in 2022 at Agricultural Biotechnology Research Center of Islamic Azad University, Ardabil. After the root growth, the root numbers, length and angle of the roots were measured. Then, HvDRO1 gene expression was measured by real-time PCR.
Research findings: The results of ANOVA showed that there are significant differences in all the traits which indicates the existence of genetic diversity among the tested cultivars. The effect of drought stress was significant on all traits, so that caused an increase in root length and HvDRO1 gene expression in both stress levels (75% FC and 50% FC), a decrease in the root numbers and an increase in the root angle under the 50% FC. Mean comparisons showed that the root length ranged from 22.4 to 30.8 cm, so that Artan had the longest root and 8 other varieties (Gaflan, Abidar, Nader, Ansar, Sararoud 1, Dobrinia, Sahand and Fasih) were ranked next. The seminal root number of cultivars ranged from 3.39 to 4.33, so that Dobrinia, Radical, Sahand, Nader and Abidar had the highest root numbers. The root growth angle varied from 69.4 to 76.8 degrees, so that cultivars Sararoud, Artan, Abider, Sahand, Fasih and Gafalan had the most vertical roots. In terms of HvDRO1 gene expression, under 75% FC, Artan, Gaflan, Nader and Sahand, and under 50% FC, Gaflan had the highest amount. The results of correlations showed that the expression rate of HvDRO1 gene showed a positive correlation with the root length under 75% FC (r=0.74*). Under 50% FC, the expression rate of HvDRO1 gene had not significant correlation with root length, but showed a positive correlation with the root angle (r=0.85**). Regression analysis showed that under 75% FC, the expression of this gene explained 55.6% of the changes in root length and under 50% FC, it explained 74.6% of the changes in the root angle, suggesting the possibility of using the HvDRO1 gene expression to select the root system architecture in barley.

Keywords

• Gene expression
• Deeper rooting
• Root system architecture
• water deficit stress

Main Subjects

• Molecular genetics