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<p><i>Aegilops tauschii,</i> a wild relative of wheat, represents a rich and diverse gene source for new alleles that can effectively enhance tolerance to biotic and abiotic stresses in wheat. This experiment aimed to identify markers associated with important morphological and physiological traits of <i>Aegilops tauschii</i> under drought stress conditions using association analysis. A total of 125 genotypes of <i>Aegilops tauschii</i> were examined over two years (2017 and 2018) under two conditions: non-stress and drought stress. Based on SSR, ISSR, and retrotransposon markers, the genetic structure of the population was divided into seven sub-populations (K = 7). Among these markers, <i>Xgwm30</i>, UBC891, and the SUKKULA-UBC834 combinations exhibited the highest PIC values, while <i>Xgwm539</i>, UBC826, and the LTR1061-UBC834 combinations displayed higher MI indices. In comparing the three types of markers, retrotransposon markers exhibited higher values for the diversity indices, indicating their superior efficiency. According to the results of the association analysis, markers significantly related to morphological traits over two years non-stress and drought stress conditions were identified. Under drought stress conditions, these markers were as follows: grain diameter—UBC811, <i>Xgwm320</i>, <i>Xgwm271</i>; grain number per spike—LTR1061-LTR2116; harvest index—UBC811; plant height—LTR1061-LTR2116, LTR1061; root length—LTR2116-UBC834, UBC840, UBC811; plant fresh weight and dry weight—<i>Xgwm271</i>. Additionally, two markers, UBC811 and UBC840, showed significant relationship with grain diameter and root length in two years, respectively. Notably, UBC811 was associated with three traits: root length, harvest index, and grain diameter. Furthermore, <i>Xgwm271</i> demonstrated significant relationships with four yield-related traits in both years. The identification of common markers for different traits can indicate genomic hotspots with pleiotropic effects or linkage of genomic regions involved in these traits. Moreover, markers demonstrating significant relationship with traits across various years or environments can be utilized in wheat breeding projects following additional validation. Considering that <i>Aegilops tauschii</i> is a source of resistance genes and drought is a major challenge in modern agriculture, identifying markers associated with genes that enhance drought resistance is crucial. This study is the first to identify markers UBC811 and <i>Xgwm271</i> with significant associations across multiple yield-related traits under drought stress over two years, revealing potential genomic hotspots with pleiotropic effects. The superior efficiency of retrotransposon markers in capturing genetic diversity offers a novel approach for enhancing wheat breeding programs targeting drought tolerance.</p>

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Genetic association analysis of grain yield-related traits in Aegilops tauschii under drought and non-stress conditions

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年10月27日

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  • Mehran Falaknaz,
  • Ali Aalami,
  • Ali Ashraf Mehrabi,
  • Danial Kahrizi,
  • Atefeh Sabouri

摘要

Aegilops tauschii, a wild relative of wheat, represents a rich and diverse gene source for new alleles that can effectively enhance tolerance to biotic and abiotic stresses in wheat. This experiment aimed to identify markers associated with important morphological and physiological traits of Aegilops tauschii under drought stress conditions using association analysis. A total of 125 genotypes of Aegilops tauschii were examined over two years (2017 and 2018) under two conditions: non-stress and drought stress. Based on SSR, ISSR, and retrotransposon markers, the genetic structure of the population was divided into seven sub-populations (K = 7). Among these markers, Xgwm30, UBC891, and the SUKKULA-UBC834 combinations exhibited the highest PIC values, while Xgwm539, UBC826, and the LTR1061-UBC834 combinations displayed higher MI indices. In comparing the three types of markers, retrotransposon markers exhibited higher values for the diversity indices, indicating their superior efficiency. According to the results of the association analysis, markers significantly related to morphological traits over two years non-stress and drought stress conditions were identified. Under drought stress conditions, these markers were as follows: grain diameter—UBC811, Xgwm320, Xgwm271; grain number per spike—LTR1061-LTR2116; harvest index—UBC811; plant height—LTR1061-LTR2116, LTR1061; root length—LTR2116-UBC834, UBC840, UBC811; plant fresh weight and dry weight—Xgwm271. Additionally, two markers, UBC811 and UBC840, showed significant relationship with grain diameter and root length in two years, respectively. Notably, UBC811 was associated with three traits: root length, harvest index, and grain diameter. Furthermore, Xgwm271 demonstrated significant relationships with four yield-related traits in both years. The identification of common markers for different traits can indicate genomic hotspots with pleiotropic effects or linkage of genomic regions involved in these traits. Moreover, markers demonstrating significant relationship with traits across various years or environments can be utilized in wheat breeding projects following additional validation. Considering that Aegilops tauschii is a source of resistance genes and drought is a major challenge in modern agriculture, identifying markers associated with genes that enhance drought resistance is crucial. This study is the first to identify markers UBC811 and Xgwm271 with significant associations across multiple yield-related traits under drought stress over two years, revealing potential genomic hotspots with pleiotropic effects. The superior efficiency of retrotransposon markers in capturing genetic diversity offers a novel approach for enhancing wheat breeding programs targeting drought tolerance.