Determination of chromosomes controlling physiological traits associated to salt tolerance in barley in seedling stage

Abstract

by these QTLs varies from 7.07 to 39.04%. Highest LOD scores were obtained for the leaf to stem ratio on chromosome 2H. QTLs for forage quality indexes (total digestible nutrient, dry organic matter digestibility, leaf to stem ratio and seed to forage ratio) were found on chromosomes 1H, 2H, 3H and 5H. QTLs for forage quantity indexes (forage wet and dry matter) were mapped on chromosomes 1H, 2H, 3H and 5H. Mapped QTLs appear to be stable between locations. Therefore, gain through marker-assisted selection (MAS) in this population would be efficient.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. Molecular marker aided selection technique for salinity tolerance, would accelerate breeding progress by increasing selection efficiency. Barley is a short-season, early maturing, diploid and self pollinating crop, thus it is an ideal model plant for genetic and physiological studies of salinity tolerance. To map the Genes/QTLs for salinity tolerance in barley, and to determine the portion of each QTL in the phenotypic variation of the related traits, 72 doubled-haploid lines derived from a cross between Steptoe and Morex were investigated. This experiment was carried out under hydroponic system in botany laboratory of Zabol University in 2008. It was arranged as a completely randomized factorial experiment, with 3 replicates and four salinity levels (0, 5, 10, 15 ds/m). Phenotypic traits such as chlorophyll contents, chlorophyll florescence (Fo, Fv, Fm/Fv), prolin and carbohydrate rates, relative water content (RWC), germination percentage, coleoptiles length, stem and radicle length and their proportion, dry and wet weight of root and shoot were measured. QTL analysis was carried out using genetic linkage map derived from 327 RFLP molecular markers and QTL cartographer software with composite interval mapping method. In general we found 111 QTLs for the all traits (20 QTLs for free salinity condition, 22 QTLs for first salinity level, 14 QTLs for second salinity level, 30 QTLs for third salinity level and 25 QTLs for the mean of these four condition). Phenotypic variations that were explained by these QTLs, changed from 7.99 to 29.55. The highest and the lowest phenotypic variances were related to stem length in proportion to radicle length in free salinity condition and Fm/Fv in first salinity level, respectively. LOD score was ranged in 2.52-6.67. The highest and the lowest LOD were attained for the QTLs of stem length in proportion to radicle length in free salinity condition (Q2sh/rs0) and stem length in first salinity level (Q2shs1). Mapped QTLs appear to be unstable between conditions. Therefore, gain through marker-assisted selection (MAS) in this population for salt tolerance would be inefficient.Salt stress as one of the most important abiotic stress plays an important role in the yield reduction of crop p...

QTL for chlorophyll fluorescence of barley plants grown at low oxygen concentration in hydroponics to simulate waterlogging

“…Various fluorescence parameters have been found to be closely correlated with carbon assimilation under different stresses in rice (Guo et al 2008), lucerne (Smethurst and Shabala 2003), soybean (Yin et al 2010), wheat ) and maize (Fracheboud et al 2004), as well as grain yield in barley (Bertholdsson 2013) and, under optimal conditions intriticale (Hura et al 2009). Fluorescence parameters has also been used for mapping QTL in relation to drought stress in wheat (Czyczyło-Mysza et al 2011), rice (Gu et al 2012) and barley (Guo et al 2008;Wójcik-Jagla et al 2013), salt tolerance in barley (Aminfar et al 2011) and biomass and yield in wheat (Czyczylo-Mysza et al 2013). However, to our knowledge there have been no previous efforts to associate chlorophyll fluorescence with WLT, besides research by Pang et al (2004) and Bertholdsson (2013), who used it to characterise WLT of barley cultivars.…”

Genetic Mapping of Quantitative Trait Loci for Yield-Affecting Traits in a Barley Doubled Haploid Population Derived from Clipper × Sahara 3771

“…In barley, the identification of QTLs underlying main agronomic traits like GY (Thomas et al, 1998; Liu et al, 2015), malting quality (Borem et al, 1999; Beecher et al, 2001), disease resistance (Chen et al, 1994; Steffenson et al, 1996), drought tolerance (Mohammadi et al, 2005; Peighambari et al, 2005), and salt tolerance (Siahsar and Narouei, 2010; Aminfar et al, 2011) has been reported using molecular markers.…”