title: Wild barley introgression lines revealed novel QTL alleles for root and related shoot traits in the cultivated barley (Hordeum vulgare L.).
abstract: BACKGROUND
  Root is the prime organ that sucks water and nutrients from deep layer of soil. Wild barley diversity exhibits remarkable variation in root system architecture that seems crucial in its adaptation to abiotic stresses like drought. In the present study, we performed quantitative trait locus (QTL) mapping of root and related shoot traits under control and drought conditions using a population of wild barley introgression lines (ILs). This population (S42IL) comprising of genome-wide introgressions of wild barley accession ISR42-8 in the cultivar Scarlett background. Here, we aimed to detect novel QTL alleles for improved root and related shoot features and to introduce them in modern cultivars.
  
  
  RESULTS
  The cultivar Scarlett and wild barley accession ISR42-8 revealed significant variation of root and related shoot traits. ISR42-8 showed a higher performance in root system attributes like root dry weight (RDW), root volume (RV), root length (RL) and tiller number per plant (TIL) than Scarlett. Whereas, Scarlett exhibited erect type growth habit (GH) as compared to spreading growth habit in ISR42-8. The S42IL population revealed significant and wide range of variation for the investigated traits. Strong positive correlations were found among the root related traits whereas GH revealed negative correlation with root and shoot traits. The trait-wise comparison of phenotypic data with the ILs genetic map revealed six, eight, five, five and four QTL for RL, RDW, RV, TIL and GH, respectively. These QTL were linked to one or several traits simultaneously and localized to 15 regions across all chromosomes. Among these, beneficial QTL alleles of wild origin for RL, RDW, RV, TIL and GH, have been fixed in the cultivar Scarlett background.
  
  
  CONCLUSIONS
  The present study revealed 15 chromosomal regions where the exotic QTL alleles showed improvement for root and related shoot traits. These data suggest that wild barley accession ISR42-8 bears alleles different from those of Scarlett. Hence, the utility of genome-wide wild barley introgression lines is desirable to test the performance of individual exotic alleles in the elite gene pool as well as to transfer them in the cultivated germplasm.
authors.affiliation: Institute of Crop Science and Resource Conservation, Crop Genetics and Biotechnology Unit, University of Bonn, Katzenburgweg 5, Bonn, 53115, Germany. a.naz@uni-bonn.de.
authors.forename: Ali Ahmad
authors.initials: AA
authors.lastname: Naz
authors.affiliation: Institute of Crop Science and Resource Conservation, Crop Genetics and Biotechnology Unit, University of Bonn, Katzenburgweg 5, Bonn, 53115, Germany. arifuzzaman@uni-bonn.de.
authors.forename: Md
authors.initials: M
authors.lastname: Arifuzzaman
authors.affiliation: Institute of Crop Science and Resource Conservation, Crop Genetics and Biotechnology Unit, University of Bonn, Katzenburgweg 5, Bonn, 53115, Germany. shumailamuzammil@yahoo.com.
authors.forename: Shumaila
authors.initials: S
authors.lastname: Muzammil
authors.affiliation: Institute of Agricultural and Nutritional Sciences, Chair of Plant Breeding, Martin-Luther-University Halle-Wittenberg, Betty-Heimann-Str. 3, Halle, 06120, Germany. klaus.pillen@landw.uni-halle.de.
authors.forename: Klaus
authors.initials: K
authors.lastname: Pillen
authors.affiliation: Institute of Crop Science and Resource Conservation, Crop Genetics and Biotechnology Unit, University of Bonn, Katzenburgweg 5, Bonn, 53115, Germany. j.leon@uni-bonn.de.
authors.forename: Jens
authors.initials: J
authors.lastname: Léon
mesh_terms: D000222:Adaptation, Physiological; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D017343:Genes, Plant; D056726:Genetic Association Studies; D001467:Hordeum / Q000235:genetics* / Q000254:growth & development; D018517:Plant Roots / Q000235:genetics* / Q000254:growth & development; D040641:Quantitative Trait Loci