Association Mapping of Morphological and Physiological Traits of Flag Leaf Related to Drought Tolerance in Barley

Abstract

Association mapping (AM) has proven to be a powerful approach for dissecting the genetic basis of complex traits. In this study, Quantitative Trait Loci (QTLs) controlling flag leaf characteristics under drought stress were detected in a set of 148 modern spring barley cultivars using AM analysis. Flag leaf length (FLL), flag leaf width (FLW), relative water content (RWC), chlorophyll content, and maximum quantum efficiency of PSII (Fv/Fm) which are important in photosynthetic rate, were evaluated under normal irrigation and drought stress conditions at grain filling stage. Population structure was estimated using Structure 2.3 and linkage disequilibrium (LD) was estimated by the 'Full Matrix LD' using Tassel 5.0. Significant marker/trait associations were investigated based on K-Q matrix using Tassel 3.0. The analysis of population structure divided the cultivars into two subgroups. Significant LD values (P < 0.01) between polymorphic sites with regions of high and low LD were observed. A total of 84 significant putative genomic regions were identified, which delineated into 37 QTLs under two water treatments. Two stable QTLs on 2H and 3H were detected for FLL in drought stress treatment. A QTL for FLL were detected on 2H in normal treatment, which alone explained around 11% of phenotypic variance of FLL. This QTL was also associated with the expression of FLW and explained around 7.5% of phenotypic variance. The results suggest that major loci are located on chromosomes 2H, 3H, 4H and 5H involved in the development of flag leaf characteristics and could be used as selection criteria in barley breeding for drought tolerance.

Identification of QTL underlying the main stem related traits in a doubled haploid barley population

“…Most of the studies on lodging focused on plant height and stem chemical composition ( JSameri et al., 2009 ; Ren et al., 2013 ; Ren et al., 2014 ; Wehner et al., 2015 ; Gong et al., 2016 ; Wendt et al., 2016 ; Al-Abdallat et al., 2017 ; Bélanger et al., 2018 ; Hu et al., 2018 ; Pu et al., 2021 ), on heading date focused on the change of agronomic traits under drought stress and panicle traits in barley ( Pasam et al., 2012 ; Long et al., 2013 ; Alqudah et al., 2014 ; Gawenda et al., 2015 ; Mohammadi et al., 2015 ; Alqudah et al., 2016 ; Kristensen et al., 2016 ; Maurer et al., 2016 ; Alqudah et al., 2018 ; Jabbari et al., 2018 ; Abdel-Ghani et al., 2019 ; Jia et al., 2019 ; Ward et al., 2019 ; Jabbari et al., 2019 ; Moualeu-Ngangue et al., 2020 ), but few studies on QTL mapping of stem diameter of internode or node were reported.…”

Barley with improved drought tolerance: Challenges and perspectives

“…Genotypes with high adaptability to drought stress may serve as genetic resources to enhance drought stress tolerance (Liaqat et al, 2021). Selection for drought tolerance has focused extensively on agronomic and physiological traits, such as grain yield (Mora et al, 2016), biomass yield (Szira et al, 2008), root morphology (Hargreaves et al, 2008), relative water content (Szira et al, 2008), stomatal conductance (Munns et al, 2010), photosynthetic parameters (Gudys et al, 2018;Rapacz et al, 2019), chlorophyll fluorescence (Guo et al, 2007;Jabbari et al, 2019;Rapacz et al, 2019), osmotic adjustment (Teulat et al, 2001a), and hormone content (Gudys et al, 2018).…”

Evaluation of a barley (Hordeum vulgare) chromosome 2 drought tolerance quantitative trait locus in genomic backgrounds of two cultivars

“…QTL mapping for barley drought tolerance was carried out using different biparental populations produced from crosses between barley cultivars (Fan et al, 2015; Teulat et al, 2002; Wójcik‐Jagła et al, 2013), between Hordeum vulgare and Hordeum spontaneum genotypes (Baum et al, 2003; Sayed et al, 2012; Talame et al, 2004) or between H. spontaneum genotypes (Chen et al, 2010). Besides, there have also been more recent genome wide association studies for drought tolerance of barley using different germplasm collections (Jabbari et al, 2019; Thabet et al, 2020; Wehner et al, 2015). In barley ‘Tadmor’ × Er/Apm mapping population, a genomic region around the EBmac0684 marker on chromosome 2 (2H) was found to be associated with drought tolerance provided by carbon isotope discrimination and osmotic adjustment (Teulat et al, 2002).…”