QTL analysis of flag leaf in barley (Hordeum vulgare L.) for morphological traits and chlorophyll content

To understand genetic patterns of the morphological and physiological traits in flag leaf of barley, a double haploid （DH） population derived from the parents Yerong and Franklin was used to determine quantitative trait loci （QTL） controlling length, width, length/width, and chlorophyll content of flag leaves. A total of 9 QTLs showing significantly additive effect were detected in 8 intervals on 5 chromosomes. The variation of individual QTL ranged from 1.9% to 20.2%. For chlorophyll content expressed as SPAD value, 4 QTLs were identified on chromosomes 2H, 3H and 6H; for leaf length and width, 2 QTLs located on chromosomes 5H and 7H, and 2 QTLs located on chromosome 5H were detected; and for length/width, I QTL was detected on chromosome 7H. The identification of these QTLs associated with the properties of flag leaf is useful for barley improvement in breeding programs.

Evaluation of Chlorophyll Content and Fluorescence Parameters as Indicators of Drought Tolerance in Barley

Drought is a major abiotic stress that severely affects food production worldwide. Agronomic and physiological traits associated with drought tolerance are suitable indicators for selection of drought tolerance genotypes to reduce the impact of water deficit on crop yield in breeding program. The objective of this study was to identify indicators related to drought tolerance through analysis of photosynthetic traits in barley （Hordeum vulgare L.）. These traits included chlorophyll content, initial fluorescence （Fo）, maximum primary yield of photochemistry of photosystem Ⅱ （Fv /Fo） and maximum quantum yield of photosystem Ⅱ （Fv/Fm）. Four genotypes （Tadmor, Arta, Morocco9-75 and WI2291） variable in drought tolerance were used to investigate the correlation between these traits and drought tolerance. The results reflected that all of these traits were affected negatively in the four genotypes at different levels of post-anthesis drought stress, but the decrease in drought tolerant genotypes was much less than that of drought sensitive genotypes. The results further revealed that the components of the photosynthetic apparatus could be damaged significantly in drought sensitive genotypes, while drought tolerant genotypes were relatively less affected. On the other hand, the values of chlorophyll content, Fo, Fv/Fo and Fv/Fm in drought tolerance genotypes were significantly higher than those in drought sensitive genotypes under drought stress. It was concluded that chlorophyll content, Fo, Fv/Fo and Fv/Fm could be considered as reliable indicators in screening barley germplasm for drought tolerance.

Alleviation of Al Toxicity in Barley by Addition of Calcium

The potential mechanism by which Ca alleviates Al toxicity was investigated in barley seedlings. It was found that 100 Al-alone treatment inhibited barley plant growth and thereby reduced shoot height and root length, and dry weights of root, shoot and leaf; promoted Al accumulation but inhibited Ca absorption in plant tissues; and induced an increase in the activities of superoxide dismutase （SOD）, catalase （CAT）, and peroxidase （POD） and in the level of lipid peroxidation （MDA content） in leaves. Except for the increase in Ca concentration in plant tissues, treatment with 0.5 mM Ca in the absence of Al had less effect on the above-mentioned parameters, compared with the control. Addition of Ca efficiently reduced Al toxicity, which is reflected by the promotion of plant growth, reduction in Al concentration and MDA content, increase in Ca concentration and in SOD, POD, and CAT activities compared with the Al-alone-treatment; with increase in Ca level （3.0 raM）, the ameliorative effect became more dominant. This indicated that the alleviation of aluminum toxicity in barley seedlings with Ca supplementation could be associated with less absorption of Al and the enhancement of the protective ability of the cell because of increased activity of the antioxidative enzyme.

Protein and hordein fraction content in barley seeds as affected by sowing date and their relations to malting quality

The effect of sowing date on grain protein, hordein fraction content and malting quality of two-rowed spring barley was investigated by using ten commercial cultivars with different grain protein content and the relationships among these traits were examined. The results showed that grain protein content and B hordein content increased as the sowing date postponed and were significantly affected by sowing date, while C and D hordein contents were less influenced by sowing date. There were significant differences in grain protein and hordein fraction content among the ten cultivars. The coefficient of variation of D hordein content was much larger than that of B and C hordein contents, suggesting its greater variation caused by different sowing dates. Beta-amylase activity and diastatic power were also significantly affected by sowing date, with malt extract being less affected. Significant differences in measured malt quality were found among the ten cultivars. Grain protein was significantly correlated with B hordein and malt extract positively and negatively, respectively. There was no significant correlation between beta-amylase activity or diastatic power and grain protein content. B hordein was negatively and significantly correlated with malt extract, but no significant correlations between C hordein, D hordein and malting quality traits.

Effects of Waterlogging on Photosynthesis and Antioxidant Enzyme Activities of Six Barley Genotypes with Different Waterlogging Tolerance

A field experiment was carried out to study genotypic difference in the effect of waterlogging on photosynthesis, chlorophyll content and antioxidative enzyme activities in barley. Waterlogging caused a rapid decline in net photosynthetic rate (Pn) and stomatal conductance (gs), and little change in chlorophyll content during early days of the treatment. A dramatic increase in malondialdehyde (MDA) content, superoxide dismutase (SOD) and peroxidase (POD) in waterlogged plants in the early days of the experiment was found, indicating the occurrence of oxidative stress in barley plants exposed to waterlogging. There was a highly significant difference in the changed extent of all these parameters among genotypes. Franklin and Yongjiahong Liuleng Damai, which were relatively sensitive to waterlogging in terms of growth, photosynthesis and chlorophyll content, accumulated much more MDA than the other two relatively tolerant genotypes (93-3143 and QS). After removal of waterlogging, the genotypic difference became much greater in recovering of these examined parameters. Yongjiahong Liuleng Damai showed higher recovery, while Franklin only recovered to 50% of the control at the 14 day after waterlogging removal. It may be concluded that it is the difference in anti-oxidative stress caused by waterlogging that account for the major difference in photosynthesis among barley genotypes.

Genotypic and Environmental Variations of Arabinoxylan Content and Endoxylanase Activity in Barley Grains

Arabinoxylan （AX） content in barley grains is an important quality determinant when barley is used as raw material of malt or beer production. The cultivar and environmental variations of total arabinoxylan （TAX）, water extractable arabinoxylan （WEAX） and endoxylanase activity （EA） were investigated using eight barley cultivars growing at seven locations with diverse environmental conditions. The results showed that both barley cultivar and location significantly affected the TAX, WEAX and EA levels, but the variations of TAX content and EA were mainly attributed to cultivar, while the impact of location on WEAX content was greater than that of cultivar. Correlation analysis indicated that TAX was significantly correlated to WUAX.

Genotypic Difference in Plant Growth and Mineral Composition in Barley Under Aluminum Stress

Four barley genotypes (Tiantaiyangdamai, Xiyin2, Mimaill4 and Tai94-Ce6) were exposed to 0, 50, 100, and 150μM of Al-containing solution with pH 4.5, to determine the differences in growth inhibition , Al concentration and accumulation and mineral composition among genotypes. The results showed that Mimaill4 and Tai94-Ce6 had significantly higher Al concentration and accumulation than Tiantaiyangdami and Xiyin2, especially in roots, and the growth traits including root and shoot dry weights, shoot height, root length and tillers per plant were more inhibited in the former two genotypes. Al treatments caused a significant reduction of N, P, K, Ca, Mg and Mn content in both roots and shoots, of Cu in shoots; and a significant increase in Fe and Zn content in both roots and shoots, of Cu in roots. The changed rates of mineral content caused by Al treatments, in terms of the content in 150μM Al divided by the content in the control, differed significantly among four genotypes. Two Al-sensitive genotypes, Mimaill4 and Tai94-Ce6 had much greater changes in mineral content than other two Al-tolerant genotypes Tiantaiyangdamai and Xiyin2 when subjected to Al stress in comparison with the control. It is indicated that the Al-tolerant genotype is characterized by less uptake and accumulation of Al in roots and smaller disorders in mineral metabolism and ion homeostasis.

Variation of Grain and Malt Qualities in Barley as Affected by Cultivars and Environments

Inferior and unstable quality of malt barley in China has limited its wide use in malting and brewing industries. In this research, eight two-rowed barley cultivars were planted at 7 locations with different ecological conditions in southern China, to investigate the cultivar and environmental effect on grain and malt qualities. The results showed that grain protein content differed dramatically among locations, but there were no significant differences among cultivars. For four malt qualities including diastatic power, wort viscosity, Kolbach index and malt extract, significant differences were found among cultivars and locations, except for diastatic power among cultivars. Coefficients of variance(CV)caused by location were greater than those caused by cultivar for each quality parameter, especially for diastatic power and Kolbach index, indicating the predominant influence of environment on malt quality. The analysis showed that grain protein content was positively related to diastatic power and wort viscosity, and negatively to malt extract. Kolbach index was positively related to malt extract, and negatively to diastatic power and wort viscosity. Diastatic power showed positive and negative correlation with wort viscosity and malt extract, respectively.

Genotypic and environmental variation in barley limit dextrinase activity and its relation to malt quality

Variation in the limit dextrinase activity of barley malt, and the relationships between limit dextrinase activity and malt quality parameters were investigated using eight cultivars grown at seven diverse locations in China for two successive years. Limit dextrinase activity varied with genotype and location, with the levels ranging from 0.245 U/g to 0.980 U/g. The results showed that the variation in limit dextrinase activity was more attributable to the environment (location and year) than to the genotype. The response of limit dextrinase activity to the environment differed markedly among cultivars, and was reflected by large difference in coefficient of variation of cultivars across diverse locations. Regression analysis showed that limit dextrinase activity was negatively correlated with malt viscosity (r=?0.52, P<0.01), positively correlated with Kolbach index (r=0.38, P<0.01) and malt extract (r=0.30, P<0.05), but had no significant correlation with malt protein content and diastatic power.

Cultivar and Environmental Effects on p-glucanase Activity in Both Barley Grain and Malt and Its Function in β-glucan Degradation

Eight two-rowed barley cultivars were grown at seven locations in the southern winter-barley zone of China. Mean grainβ-glucanase activity ranged from 39.89 U kg-1 for Suyin2 to 49.75 U kg-1 for Xi-umai3 in 8 cultivars grown at 7 locations, and from 38. 74 U kg-1 in Zhengzhou to 57. 96 U kg-1 in Putian among 7 locations on an average of all cultivars. Correspondingly, mean malt β-glucanase activity of 8 cultivars ranged from 313.33 U kg-1 for ZAU3 to 489. 89 U kg-1 for Daner Barley, and of 7 locations from 330.40 U kg-1 in Yancheng to 418. 24 U kg-1 in Putian. There were significant differences among cultivars and locations in maltβ-glucanase activities. The locations showed much larger variation in maltβ-glucanase activities than cultivars. The reduction of total β-glucan content after malting varied in both cultivars and locations, with a mean of 78.31%. The analysis of correlations showed that maltβ-glucan content was significantly positively and negatively correlated with grain β-glucan content and malt β-glucanase activity, respectively, and malt β-glucanase activity was significantly positively correlated with grain β-glucanase activity.

The influence of drought stress on malt quality traits of the wild and cultivated barleys

As a major abiotic stress,drought causes instability and deterioration of malt barley quality.There is distinct difference among barley cultivars in the responses of the main malt quality traits to drought stress.In the previous study,we identified some Tibetan wild barley accessions with relatively less change of malt quality traits under drought.In this study,we examined the impact of drought stress during grain filling stage on grain weight and several important malt quality traits,including total protein content,β-glucan content,limit dextrinase activity,β-amylase activity,and protein fractions in four barley genotypes(two Tibetan wild accessions and two cultivars).Drought treatment reduced grain weight,β-glucan content,and increased total protein content,β-amylase activity.These changes differed among barley genotypes and treatments,and are closely associated with grain filling process and kernel weight.All the results indicated Tibetan wild barley had great potential for developing drought tolerant barley cultivars.Relatively stable kernel weight or filling process under water stress should be highlighted in malt barley breeding in order to reduce the effect of water stress on malt barley quality.

Relationship of Grain Fructan Content to Degree of Polymerisation in Different Barleys

Fructans are important in the survival of plants and also valuable for humans as potentially health promoting food ingredients. In this study fructan content and composition were determined in grains of 20 barley breeding lines and cultivars with a wide variation in chemical composition, morphology and country of origin, grown at one site in Chile. There was significant genotypic variation in grain fructan content ranging from 0.9% to 4.2% of grain dry weight. Fructan degree of polymerisation (DP) was analysed using high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Changes in the distribution of different chain lengths and the pattern of structures of fructan were detected with increasing amount of fructan in the different barleys. A positive correlation was found between fructan content and the relative amount of long chain fructan (DP > 9) (r = 0.54, p = 0.021). Our results provide a basis for selecting promising barley lines and cultivars for further research on fructan in barley breeding with the aim to produce healthy food products.

Assessing the product quality and biological activities of barley(Hordeum vulgare L.)grasses at different harvest times

Barley(Hordeum vulgare L.)grasses(BG)have attracted considerable interest due to their multiple physiological activities and health benefits.In this paper,eight BG at four different growth stages were collected:seedling,tillering,stem elongation,and heading,and their product qualities and biological activities were examined and studied.Results demonstrated that harvest time obviously influenced proximate composition,surface color,and amino acid profile.Z21 and Z23 harvested at the seedling and early tillering stages,respectively,had higher total phenolic content(TPC)and total flavonoid content(TFC)than the other BG.Moreover,Z21 and Z23 possessed better DPPH radical-scavenging ability,antioxidant capacity,andα-glucosidase inhibitory activity,which were positively correlated with TPC,TFC,and protein and total amino acid contents.Our findings suggested that the early tillering stages were the preferable harvest times for BG with good product quality and biological properties.

GREEN PLANT REGENERATION FROM PROTO PLASTS OF BARLEY (Hordeum vulgate L.)

Barley is the world’s fourth leading cereal in acreage planted, after wheat, rice and corn. Nevertheless, whilst plant regenerations from protoplast cultures of rice, corn and wheat were realized one after another during the past few years, only albinos were regenerated sporadically from barley protoplasts. The present note reports that a group of complete green plants has been obtained from protoplasts isolated from cell suspension cultures in barley.

转TRXS基因啤酒大麦种子中硫氧还蛋白H与淀粉酶活性变化

导入TRXS基因后,转基因大麦籽粒的硫氧还蛋白H活性明显提高;淀粉酶活性也明显提高,其中Α-淀粉酶活性在开花后30D提高了3倍以上,随着籽粒的发育,转基因对Α-淀粉酶活性影响作用减少,对Β-淀粉酶活性的影响有同样的趋势;转基因大麦种子发芽势明显提高。说明TRXS基因有望改善啤酒大麦的制麦特性和品质特性。

Identification of QTLs for yield and yield components of barley under different growth conditions

Waterlogging is a major abiotic stress limiting barley (Hordeum vulgare L.) yield and its stability in areas with excessive rainfall.Identification of genomic regions influencing the response of yield and its components to waterlogging stress will enhance our understanding of the genetics of waterlogging tolerance and the development of more tolerant barley cultivars.Quantitative trait loci (QTLs) for grain yield and its components were identified using 156 doubled haploid (DH) lines derived from a cross between the cultivars Yerong (waterlogging-tolerant) and Franklin (waterlogging-sensitive) grown under different conditions (waterlogged and well drained).A total of 31 QTLs were identified for the measured characters from two experiments with two growth environments.The phenotypic variation explained by individual QTLs ranged from 4.74% to 55.34%.Several major QTLs determining kernel weight (KW),grains per spike (GS),spikes per plant (SP),spike length (SL) and grain yield (GY) were detected on the same region of chromosome 2H,indicating close linkage or pleiotropy of the gene(s) controlling these traits.Some different QTLs were identified under waterlogging conditions,and thus different markers may have to be used in selecting cultivars suitable for high rainfall areas.