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Barley traits related to salt tolerance are mapped in a population segregating for a dwarfing gene associated with salt tolerance. Twelve quantitative trait loci (QTLs) were detected for seven seedling traits in doubled haploids from the spring barley cross Derkado x B83-12/21/5 when given saline treatment in hydroponics. The location of QTLs for seedling growth stage (leaf appearance rate), stem weight prior to elongation, and tiller number are reported for the first time. In addition, four QTLs were found for the mature plant traits grain nitrogen and plot yield. In total, seven QTLs are co-located with the dwarfing genes sdw1, on chromosome 3H, and ari-e.GP, on chromosome 5H, including seedling leaf response (SGa) to gibberellic acid (GA(3)). QTLs controlling the growth of leaves (GS2) on chromosomes 2H and 3H and emergence of tillers (TN2) and grain yield were independent of the dwarfing genes. Field trials were grown in eastern Scotland and England to estimate yield and grain composition. A genetic map was used to compare the positions of QTLs for seedling traits with the location of QTLs for the mature plant traits. The results are discussed in relation to the study of barley physiology and the location of genes for dwarf habit and responses to GA.

10 Abstract The genetic basis of several different 11 components of resistance to Rhynchosporium secalis 12 in barley was investigated in a mapping population 13 derived from a cross between winter and spring 14 barley types. 34Rhynchosporum secalis (Oudem) J.J. Davis, the 35 pathogen that causes 'rhynchosporium', 'barley leaf 36 blotch ' or 'scald', in Hordeum vulgare L. (barley). is 37 one of the most economically important barley 38 pathogens worldwide, particularly in cool humid 39 environments, causing reductions in both yield and 40 grain quality (Zhan et al. 2008). Average yield losses 41 (from Canada) have been estimated at 5-10% (Tur-42 kington et al. 1998), though losses of up to 40% have 43 been reported under conditions favourable for the 44 disease (Xi et al. 2000). Mapping studies have located 45 a number of major resistance (R) genes and quanti-46 tative trait loci (QTL) affecting expression of resis-47 tance to R. secalis; these are predominantly located 48 on barley chromosomes 2H, 3H and 7H (Zhan et al. 49 2008). Whilst current control strategies in the UK 50 frequently include a fungicide treatment, commercial 51 cultivars with good levels of resistance, probably due ; it has been the main winter barley malting culti-166 var grown by farmers over this period. It was initially 167 rated as having a good resistance to R. secalis,b e i n g 168 rated '8', on a 1-9 scale of increasing host resistance as 169 described in the recommended list protocols (www. 170 hgca.com). Leonie originally had the best rating of '9,' 171 but its resistance rating had declined to '5.9' by 2010 172 (www.hgca.com). Cv Cocktail was first recommended 173 for cultivation in the UK in 2003 and was formerly an 174 accepted spring barley malting cultivar in the UK. It 175 does not possess either of the two R genes for resistance 176 to R. secalis found in current UK spring barley cultivars 177 and had a moderate resistance rating of '5' when first 178 recommended, which had increased slightly to '5.9' in 179 the 2010 recommended list (www.hgca.com). 180 WB05-13 was bred to combine the resistance to 181 R.secalis and BaYMV-1 of Leonie with the accepted 182 malting quality attributes of Pearl; thus progeny from 183 its cross with Cocktail are expected to segregate for 184 resistance to R. secalis and to BaYMV-1 as well as 185 for the sdw1 dwarfing gene found in Cocktail. In 186 addition, WB05-13 has the Vrs1.t allele at the VRS1 187 locus on chromosome 2H and the mapping popula-188 tion therefore also segregates for the deficiens ear 189 type. Over 800 individual plants were derived from 190 microspore culture of the F 1 progeny; 550 lines were 191 fertile and produced sufficient seed for a field 192 multiplication plot that was sown at the James Hutton 44Author Proof (2007/2008 and 2008/2009) at the 271 James Hutton Institute rhynchosporium disease nurs-272 ery (Table 1). Cocktail, Leonie and Pearl together 273 with seven other controls were included in the trial to 274 give a trial with 200 entries. Field trials were...

SUMMARYThis paper reviews the results of several years' study by a multidisciplinarj? team comprising geneticists, physiologists, ecologists and statisticians of abiotic stress tolerance in barle5^ The strategy involves genetic fingerprinting of wild barley lines (Hordeum spontaneum C. Koch) from a range of habitats and testing these for responses to abiotic stresses under controlled conditions. Multiple regression analysis is used to identify genetic markers associated with experimentally determined stress responses. These data are related to site-of-origin ecogeographic data and used to identify areas of useful wild variation. Markers associated with traits of interest can be mapped in genetic mapping populations, revealing areas of the barley genome carrying genes controlling stress responses. This paper highlights our work on associations of amplied fragment length polymorphisms with salt tolerance and describes some initial results of the use of SSRs in studying drought tolerance in barley.

Wild barley, Hordeum spontaneum C. Koch, is the progenitor of cultivated barley, Hordeum vulgare. The centre of diversity is in the Fertile Crescent of the Near East, where wild barley grows in a wide range of conditions (temperature, water availability, day length, etc.). The genetic diversity of 39 wild barley genotypes collected from Israel, Turkey and Iran was studied with 33 SSRs of known map location. Analysis of molecular variance (AMOVA) was performed to partition the genetic variation present within from the variation between the three countries of origin. Using classification tree analysis, two (or three) specific SSRs were identified which could correctly classify most of the wild barley genotypes according to country of origin. Associations of SSR variation with flowering time and adaptation to site-of-origin ecology and geography were investigated by two contrasting statistical approaches, linear regression based on SSR length variation and linear regression based on SSR allele class differences. A number of SSRs were significantly associated with flowering time under four different growing regimes (short days, long days, unvernalised and vernalised). Most of the associations observed could be accounted for by close linkage of the SSR loci to earliness per se genes. No associations were found with photoperiodic and vernalisation response genes known to control flowering in cultivated barley suggesting that different genetic factors may be active in wild barley. Novel genomic regions controlling flowering time in wild barley were detected on chromosomes 1HS, 2HL, 3HS and 4HS. Associations of SSRs with site-of-origin ecological and geographic data were found primarily in genomic regions determining plant development. This study shows that the analyses of SSR variation by allele class and repeat length are complementary, and that some SSRs are not necessarily selectively neutral.