Abstract
Drought is a major environmental stress threatening wheat (Triticum aestivum L.) productivity worldwide. Although drought impedes wheat performance at all growth stages, it is more critical during the flowering and grain-filling phases and results in substantial yield losses. In this context, stem water-soluble carbohydrates (SWSC) were dissected at flowering and grain filling stages under drought stress (DS) and well-watered (WW) conditions using a population consisted of 116 wheat accessions in this research. The main goal was to dissect the genetic basis of water-soluble carbohydrates and the agronomic traits using association mapping approach and identify linked molecular markers. The results showed significant and positive correlations for stem water-soluble carbohydrates at grain filling (SWSCG) with accumulating efficiency of stem water-soluble carbohydrates (AESWSC) and grain filling efficiency at the late stage (GFEL). The accumulating and grain filling efficiency at grain filling stage could play an important role for SWSC especially under DS condition. Four favorable alleles for plant height (PH) and grain yield (GY) were identified in two water environments. Xbarc78-4A163and Xbarc78-4A155 were variant alleles for PH which were identified in both water regimes. Whereas Xwmc25-2D151 and Xgwm165-4B191 positively linked with GY in WW. Although Xwmc420-4A121and Xwmc112-2D215 were alleles for stem water-soluble carbohydrates at flowering (SWSCF) and SWSCG in DS but the frequency were < 5% so they were considered as rare alleles. These SSR markers which explained significant level of phenotypic variability for chosen traits could be used for selection of genotypes in wheat breeding programs through marker-assisted selection.
Highlights
Wheat is one of the three major cereals
It is inferred that stem water-soluble carbohydrates (SWSC) were accumulated more at grain filling stage in drought stress (DS) and it is considered as increase fructans for self-protection
High heritability estimated for stem water-soluble carbohydrates at grain filling (SWSCG) under drought stress
Summary
Wheat is one of the three major cereals. Global annual production is 727.87 million metric tons in 2014-2015 (USDA, 2016). Genomic approaches enable the identification and selection of chromosome regions harboring genes/QTLs (Quantitative trait loci) controlling agronomic traits and yield in crops (Collins et al, 2008; Cooper et al, 2009; Tuberosa & Salvi, 2006). Among such approaches, association mapping is increasingly being adopted as a method complementary to traditional bi-parental linkage mapping to identify genotype-phenotype associations i.e. molecular marker-trait associations (Sorrells & Yu, 2009; Waugh et al, 2009)
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