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.
"Salt effected soils can be brought under cultivation by producing salt tolerant germplasm. This involves identification of wheat gemplasm on the basis of physiological and biochemical traits that are tolerant to salinity or using new genetic resources to introduce new genes for salt tolerance into existing cultivars (Farshadfar et al., 2008). A method of introducing novel genes into hexaploid bread wheat is through synthetic hexaploid wheats via bridge crossing, which are produced from interspecific crosses between tetraploid Triticum turgidum L. (2n=4x=28; AABB) and diploid Aegilops tauschii (Coss) Schmal. "
[Show abstract][Hide abstract] ABSTRACT: Salinity is one of the major abiotic stresses affecting plant growth and development as salinization of cultivated land is increasing globally. There is considerable variation in salinity tolerance of wheat genotypes and selection of salt tolerant genotypes is of great interest in salt affected regions. An experiment was conducted to evaluate the salt tolerance of 13 newly developed synthetic hexaploid wheats (2n=6x=42; AABBDD) along with two check varieties Kharchia-65 and Shorawaki. Thirteen-day-old seedlings, grown in a hydroponics system, were subjected to 0, 75 and 150 mM NaCl in Hoagland’s nutrient solution for five days. Increasing salt stress generally affected all physiological aspects of the plants; however, various enzyme activities, proline content, soluble sugars and protein content increased with increased salt concentration. Exposure to salt stress affected plant dry biomass of all the genotypes; however, there was a difference in response of wheat genotypes to salinity stress. Among the tested genotypes, Kharchia-65, Shorawaki, N-7, N-9 and N-13 showed better performance in terms of plant biomass, K+: Na+ ratio, chlorophyll content, net assimilation rate (A), transpiration rate (E) and stomatal conductance (gs). There was a strong correlation between K+:Na+ ratio, chlorophyll, proline, SOD, CAT and gs against shoot dry biomass. Based on overall performance, the tested wheat genotypes were grouped as tolerant, moderately tolerant and sensitive. Wheat genotypes N-7, N-9 and N-13 were grouped as tolerant, N-33 and N-12 as moderately tolerant and the remaining genotypes were found sensitive to salt stress. In this regard K+:Na+ ratio, chlorophyll, proline, SOD, CAT and gs may be used as potential biochemical and physiological selection criteria for screening of salt tolerance in wheat genotypes.
International Journal of Agriculture and Biology 04/2014; · 0.90 Impact Factor
[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] 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 08/2012; 7(8):e43079. DOI:10.1371/journal.pone.0043079 · 3.23 Impact Factor
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