Locating QTLs Controlling Salt Tolerance in Barley Using Wheat-Barley Disomic Addition Lines
ABSTRACT In order to investigate the chromosome(s) involved in salt tolerance based on criteria such as Na+, K+ and K+/Na+ discrimination, Stress Tolerance Index (STI) and Multiple Selection Index (MSI), an experiment was carried out under hydroponics culture using a wheat-barley chromosome addition lines. The results of this investigation based on the morphological, physiological and statistical analysis proved the hypothesis that most of the genes controlling traits affecting salt tolerance are located on chromosomes 4H and 5H. Though, chromosome 6H was also ranked among the genotypes with high STI and MSI, this may show that this chromosome carry QTLs affect on salt tolerance, as well. However, higher Na+ and lower K+/Na+ values of this line compared to 4H and 5H show the less effectiveness of this line on salt tolerance. Carrying higher positive traits on chromosome 4H compared to the 5H and 6H may indicate that the 4H chromosome has proportion of positive genes controlling salinity tolerance. The addition line carrying 4H chromosome of barley can be used in wide hybridization programs to transfer useful salt tolerance genes into wheat germplasm. This line may also be used in QTL mapping in the basic research programs.
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ABSTRACT: Salinity and waterlogging are two major abiotic stresses severely limiting barley production. The lack of a reliable screening method makes it very hard to improve the tolerance through breeding programs. This work used 188 DH lines from a cross between a Chinese landrace variety, TX9425 (waterlogging and salinity tolerant), and a Japanese malting barley, Naso Nijo (waterlogging and salinity sensitive), to identify QTLs associated with the tolerance. Four QTLs were found for waterlogging tolerance. The salinity tolerance was evaluated with both a hydroponic system and in potting mixture. In the trial with potting mixture, only one major QTL was identified to associate with salinity tolerance. This QTL explained nearly 50% of the phenotypic variation, which makes it possible for further fine mapping and cloning of the gene. This QTL was also identified in the hydroponic experiment for different salt-related traits. The position of this QTL was located at a similar position to one of the major QTLs for waterlogging tolerance, indicating the possibility of similar mechanisms controlling both waterlogging and salinity tolerance. The markers associated with the QTL provided a unique opportunity in breeding programs for selection of salinity and waterlogging tolerance.PLoS ONE 01/2012; 7(8):e43079. · 3.53 Impact Factor
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ABSTRACT: Salinity stress is a major limitation in barley production. Substantial genetic variation in tolerance occurs among genotypes of barley, so the development of salt-tolerant cultivars is a potentially effective approach for minimizing yield losses. The lack of economically viable methods for screening salinity tolerance in the field remains an obstacle to breeders, and molecular marker-assisted selection is a promising alternative. In this study, salinity tolerance of 172 doubled-haploid lines generated from YYXT (salinity-tolerant) and Franklin (salinity-sensitive) was assessed in glasshouse trials during the vegetative phase. A high-density genetic linkage map was constructed from 76 pairs of simple sequence repeats and 782 Diversity Arrays Technology markers which spanned a total of 1,147 cM. Five significant quantitative trait loci (QTL) for salinity tolerance were identified on chromosomes 1H, 2H, 5H, 6H and 7H, accounting for more than 50% of the phenotypic variation. The tolerant variety, YYXT, contributed the tolerance to four of these QTL and Franklin contributed the tolerance to one QTL on chromosome 1H. Some of these QTL mapped to genomic regions previously associated with salt tolerance in barley and other cereals. Markers associated with the major QTL identified in this study have potential application for marker-assisted selection in breeding for enhanced salt tolerance in barley.Molecular Breeding 01/2012; · 3.25 Impact Factor