Journal of Food, Agriculture and Environment

Mapping QTLs of physiological traits associated with salt tolerance in ‘Steptoe’בMorex’ doubled haploid lines of barley at seedling stage

Author(s):

B. A. Siahsar ^1*, M. Narouei ²

Recieved Date: 2009-12-12, Accepted Date: 2010-04-08

Abstract:

Salt stress as one of the most important abiotic stress plays an important role in the yield reduction of crop plants worldwide. It is now recognized that tolerance to salinity is genetically and physiologically complex and also inherited quantitatively. In order to map the Genes/QTLs for salt tolerance, and to determine the portion of each QTL in the phenotypic variation of the physiological traits in barley, 72 doubled-haploid lines derived from a cross between ‘Steptoe’ and ‘Morex’ were investigated. This experiment was carried out under hydroponic system in Research Lab of Zabol University in 2009. It was arranged as a completely randomized factorial experiment, with 3 replicates and 4 salinity levels (0, 5, 10, 15 dS/m). Seven physiological traits including chlorophyll content, chlorophyll fluorescence (Fo, Fv, Fm/Fv), proline, water soluble carbohydrate (WSC) and relative water content (RWC) were studied. There were significant differences among the lines and different salinity levels for all studied traits. Maximum correlation was observed between Fo and Fm/Fv (r = 0.92**). QTL analysis was carried out using genetic linkage map derived from 327 molecular marker of RFLP and QTL cartographer software with composite interval mapping method. In general we found 29 QTLs for the traits (13 QTLs in free salinity condition, 17, 18 and 22 QTLs, respectively, in first, second and third salinity levels and 23 QTLs in the mean of these four conditions). Phenotypic variations that were explained by these QTLs changed from 8.63 to 44.69. The highest and the lowest phenotypic variations were related to Fv and chlorophyll content QTLs (QFv2H and QCh7Ha) in mean of four condition and third salinity level, respectively. LOD scores ranged from 3.01 to 15.97. The lowest and the highest LOD scores were attained for the QTLs of chlorophyll content in mean of four conditions (Qch2Ha) and WSC in second salinity level (QWSC2H). Several QTL co-locations confirm the observed correlations among the traits. Some of detected QTLs appear to be quite stale between four salinity levels. Therefore, gain through marker-assisted selection (MAS) in this population would be unlimited.

Keywords:

QTL, salinity, tolerance, barley, physiological traits

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Journal: Journal of Food, Agriculture and Environment
Year: 2010
Volume: 8
Issue: 2
Category: Agriculture
Pages: 751-759

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