Genetic and environmental variation in the diastatic power of australian barley

Variation in the diastatic power of Australian barley, and the relationships between diastatic power and the starch-degrading enzymes contributing to diastatic power, were investigated in 11 cultivars of barley grown at six diverse locations in Australia. Diastatic power varied with genotype and location, with the levels ranging from 3·1 to 16·5 U/kg. For alpha-amylase activity, levels across cultivar and location ranged from 52 to 214 U/g, for beta-amylase activity they ranged from 201 to 1550 U/g; and, for limit dextrinase activity, they ranged from 56 to 636 U/kg. Alpha-amylase (r = 0·64) and beta-amylase (r=0·77) activities were correlated more strongly with diastatic power than was limit dextrinase (r=0·37). Grain nitrogen content was correlated positively with diastatic power (r=0·71), largely because of the relationship between nitrogen content and beta-amylase activity (r=0·82). High grain nitrogen contents were also associated with small grain sizes (r=−0·76) and low hot-water extracts (r=−0·75). The levels of alpha-amylase activity were correlated more closely with limit dextrinase activity (r=0·65) than with beta-amylase activity (r=0·28). The results indicate the need to select barley cultivars separately for alpha-amylase and beta-amylase activities to achieve high levels of diastatic power.     

Baking quality of emmer-derived durum wheat breeding lines

Durum wheat (Triticum turgidum L. var. durum) is used predominantly for pasta products, but there is increasing interest in using durum for bread-making. The goal of this study was to assess the bread-making potential of 97Emmer19, an Emmer wheat (Triticum turgidum L. var. dicoccum) and in breeding lines derived from crosses of 97Emmer19 with adapted durum wheat cultivars. 97Emmer19 and its progeny were evaluated in 2005 and 2006 along with five durum wheat cultivars. Three bread wheat (Triticum aestivum L.) cultivars were included as checks to provide a baseline of bread making quality observed in high quality bread wheat cultivars. 97Emmer19 exhibited higher LV than all the durum wheat checks and approached the LV achieved with the bread wheat cultivar ‘AC Superb’. Breeding lines derived from 97Emmer19 had higher LV than those of the durum wheat checks, confirming that this trait was heritable. In general, durum wheat cultivars with elevated gluten strength and/or increased dough extensibility were noted to have higher LV. Dough extensibility appeared to be a more critical factor as gluten strength increased. These results indicate that there is potential to select for genotypes with improved baking quality in durum breeding programs.     

Yield response to pre-emergence control of broad-leaved weeds in winter cereals with isoxaben in France

A series of 59 trials was designed to assess the yield response to the control of broad-leaved weeds in winter cereals in the 1982/83, 1983/84 and 1984/85 seasons. When apllied pre-emergence to winter cereals, isoxaben provided season-long control of a wide spectrum of broad-leaved weeds including Veronica spp., Viola spp., Stellaria media, Aphanes arvensis, Papaver rhoeas and Matricaria spp. In 22 trials on winter barley and 37 trials on winter wheat treated pre-emergence with isoxaben in the autumn, mean yield increases of 0 · 22 t/ha and 0 · 14 t/ha respectively were recorded over that produced by herbicide combinations applied as post-emergence treatments in the spring. The mean yield increases with isoxaben over untreated controls were 0 · 30 t/ha and 0 · 26 t/ha on winter barley and winter wheat respectively.     

意大利硬粒小麦和面包小麦推广品种对白粉病的抗性

本文介绍了意大利近年来小麦主要推广品种（80个硬粒小麦品种和7 3个面包小麦品种）1992－1996年在田间对白粉病的成株抗性情况，和13个意大利硬粒小麦和20个面包小麦品种及11个中国小麦品种（系）用意大利10个主要菌系进行的苗期抗性鉴定情况。在田间成株抗性监测中，12．2％和58．9％的硬粒小麦品种和面包小麦器分别表现抗病或中抗；在苗期抗性鉴定中，参试的很多中国品种（系）对大部分意大利菌株表现免疫、近免疫或高抗。由于意大利小麦品种或含有其亲本血缘的中国品种曾经在我国小麦育种和生产中起过比较重要的作用，因此希望这些信息对育种和植病工作者有所帮助。     

Effect of Triticum monococcum glutenin loci on cookie making quality and on predictive tests for bread making quality

The effects of Triticum monococcum glutenin loci on cookie making quality and predictive tests for bread making quality were evaluated in recombinant substitution lines (RSLs) between chromosome 1A^m from T. monococcum and chromosome 1A from Chinese Spring. All four combinations of high molecular weight (H M_r-GS) and low molecular weight glutenin alleles (L M_r-GS) were studied in a factorial design to evaluate their interactions. Grain protein content was used as a covariable to evaluate the effect of these loci independently of the variation in protein content among lines. No significant interactions were detected indicating an additive effect. RSLs carrying the HM_r -GS from T. monococcum showed a 13·6% increase in SDS sedimentation volume (p=0·004) and a significant reduction in cookie diameter (−5·2%,p =0·02), and cookie quality (−6·8%, p=0·02). RSLs carrying the LM_r -GS from T. monococcum showed a significant decrease in the proportion of polymeric protein (−2·8%, p<0·0001), SDS sedimentation volume (−8·1%,p =0·03) and gluten strength (−16·5%, p=0·01), and a significant increase in cookie quality (5·9%, p=0·05). The T. monococcum LM_r. -GS allele has potential value to be used in soft wheat breeding programs. These results suggest that diploid T. monococcum could be a valuable source for new allelic variation for storage proteins loci and new quality characteristics.     

Do barley and wheat (bread and durum) differ in grain weight stability through seasons and water-nitrogen treatments in a Mediterranean location?

Under Mediterranean environments, farmers usually prefer to sow barley rather than wheat as it is generally believed that barley yields more under stressful conditions. As terminal stresses such as high temperature and water are common constraints in Mediterranean regions, higher grain weight stability may confer a clear advantage in order to maintain higher yields. The objective of the present study was to compare the stability in terms of grain weight and its components for barley, bread wheat, and durum wheat, exploring a wide range of nitrogen and water availabilities in experiments conducted in a Mediterranean region. Grain weight ranged from 23.8 to 47.7 mg grain⁻¹, being higher for durum wheat than barley and bread wheat. Durum wheat presented higher variability both in maximum grain filling rate and duration of grain filling period than bread wheat or barley. The three species responded similarly in terms of grain nitrogen content to changes in the environmental conditions explored. It is concluded that in terms of grain weight barley is as stable as bread wheat. However, durum wheat presented a lower stability than barley and bread wheat.     

Elastic properties of gluten representing different wheat classes

Traditional instruments used to evaluate dough and/or gluten rheological properties do not provide unambiguous separation of elastic and viscous behaviors. Recovery after shear creep and cyclic large deformation cyclic tensile testing were used here to decouple elastic and viscous effects. A large variation in the recoverable shear strain (∼7.2% to ∼28%) was seen for glutens from 15 U.S. popular common wheat cultivars with varying HMW subunits. Sedimentation values ranged from 29 to 57 ml for 12 hard wheat cultivars and 15 to 22 ml for three soft wheat cultivars. The tensile force at 500% extension ranged from 0.12 to 0.67 N for hard wheat glutens and from 0.10 to 0.20 for soft wheat glutens. However, the recoverable work after large extension was less than 40% of the total work of extension. In addition, recoverable work in tensile testing was highly correlated with the total work of extension (r² = 0.97) and mixograph mix times (r² = 0.81). Good to excellent bread volume was obtained for several cultivars from this sample set. This suggests that optimizing water absorption for mixing doughs to achieve maximal bread volume compensates for the wide range of viscoelastic behaviors of gluten.     

Phenolics in the bran of waxy wheat and triticale lines

The present study was designed to determine total phenolic acid contents (TPC) and compositions of bran from newly developed near-isogenic waxy wheat and triticale translocation lines. Two waxy wheat sets, Svevo (durum) and N11 (bread wheat), consisting of partial and waxy null lines and four sets of triticales (GDS7, Trim, Rhino and Rigel) having translocations at 1A.1D and 1R.1D with high molecular weight glutenin subunits (HMW-GS) 5 + 10 and 2 + 12 were investigated. Similar to non-waxy wheat, ferulic acid was the predominant phenolic acid found in waxy wheats analyzed. Two other major phenolics include p-coumaric and vanillic acids followed by lesser quantities of syringic acid. Waxy lines had higher TPC than the parent line in the N11 set, whereas the Svevo set showed the opposite trend. TPC of waxy bread wheats were correlated with amylose fractions in which the order was complete waxy < double waxy nulls < single waxy nulls. Lines with HMW-GS 2 + 12 have lower TPC than other lines in each group of triticales, except the Trim set. TPC was negatively correlated (r = −0.41; p > 0.1) with bran yields in triticale lines studied, indicating that variation in phenolics was not only due to bran yields but also to genotypic differences.     

Antioxidant activity of small grain cereals caused by phenolics and lipid soluble antioxidants

In this study, the content of soluble, free forms of phenolic compounds (total phenolics, flavonoids, PVPP (polyvinylpolypyrrolidone) bound phenolics, proanthocyanidins and phenolic acids), as well as the content of carotenoids and tocopherols, were determined in whole grains of bread and durum wheat, rye, hull-less barley and hull-less oat, each represented with four genotypes. Antioxidant activity was evaluated as radical scavenging activity with DPPH (2,2-diphenyl-1-picrylhydrazyl) reagent, as well as by hydrogen transfer reaction (reduction power) based on the reduction of Fe³⁺. Generally, a considerable variation in antioxidant activities and phytochemical contents was observed between the cereals. Remarkably higher DPPH radical scavenging ability and reducing power were detected in hull-less barley, followed by rye and hull-less oat and durum and bread wheat, indicating that small grain species have different major antioxidants with different properties. Hull-less barley had the highest content of total free phenols, flavonoids, PVPP bound phenolics and contained flavan-3-ols, not found in other species. Hull-less oat had the highest content of tocopherols, very high content of yellow pigments and PVPP bound phenolics. Ferulic acid was the major free phenolic acid in small grain cereals tested. The relationship between the content of soluble phenols, as well as reducing power and DPPH^• scavenging activity are also considered.     

Instrumental Texture of White Salted Noodles Prepared from Recombinant Inbred Lines of Wheat Differing in the Three Granule Bound Starch Synthase (Waxy) Genes

Texture is a key quality determinant of white salted noodles (WSN). Recombinant inbred lines (RILs) (n=130) of wheat with all combinations of the three Waxy genes provided a unique opportunity to relate granule bound starch synthase (GBSS) gene dosage with the texture of WSN using texture profile analysis. Harder noodles tended to be more adhesive and chewier (r=−0·68 and 0·97, respectively), whereas a reduction in adhesiveness was correlated with greater cohesiveness (r=0·65), springiness (r=0·72), and resilience (r=0·66). Cohesiveness and resilience were highly correlated (r=0·94). Highly significant variation existed among the RILs for all noodle texture parameters. Normal starch RIL noodles tended to produce the hardest, most adhesive and chewy, but least cohesive, springy and resilient noodles. Full waxy RIL noodles were the softest, thickest, least adhesive and chewy, and most cohesive and springy. Partial waxy RIL noodles generally were intermediate in texture. The GBSS genotype comprised 27–68% of the variance of noodle texture compared to 27–60% variance for RILs within GBSS class. Based on these results, starch composition is a major contributor to the texture of white salted noodles.     

Bread making quality of durum wheat genotypes with some novel glutenin subunit compositions

Durum wheat genotypes with some novel high M_r (high molecular weight, HMW) and low M_r (low molecular weight, LMW) glutenin subunits were grown in Sicily for two years of testing in order to compare their rheological and baking properties with respect to commercial durum wheat cultivars. Good bread making quality, as measured by Alveograph W and P/L, Farinograph and Mixograph parameters, and loaf volume was observed in genotypes combining high M_r subunits 2⁺, 1 or 11 encoded at the Glu-A1 locus with the so-called LMW-2 subunit group encoded at the Glu-B3 locus. The cultivar Avanzi, which carries high M_r subunit 2⁺ and LMW-2-like subunits, and the cultivars Dritto and Keops, which contain novel high and low M_r subunits, gave higher loaf volumes than control cultivars. The LMW-2 group subunits were found to be the main factor in determining dough strength (Alveograph W). The increase in the amount of high M_r subunits in genotypes with one expressed Glu-A1 gene may account for their improved rheological and baking properties.     

The effect of systemic fungicides,applied as seed treatments or early foliar sprays,on speckled leaf blotch of wheat, Mycosphaerella graminicola (Fuckel) Schroeter

Control of speckled leaf blotch (Mycosphaerella graminicola) of wheat (Triticum aestivum) with systemic fungicides used as seed treatments or foliar sprays was studied. Seed treatment with either imazalil (1·125 g/kg seed), nuarimol (0·2 g/kg), thiabendazole (1·5 and 0·75 g/kg), triadimenol (0·3 and 0·2 g/kg) or Shell WL 47675 (0·415 g/kg) reduced the number of infected plants by 28–62% when assessments were made 11 weeks after sowing. Thiabendazole (1·5 and 0·75 g/kg) and triadimefon (0·3 and 0·2 g/kg) slowed the development of speckled leaf blotch for c. 15 weeks after sowing. A single foliar spray of triadimefon (125 g/ha) slowed the development of the disease for c. 10 weeks, but a single spray of benomyl controlled it for the whole season. There was no additional benefit from combining a seed treatment of triadimefon (0·225 g/kg) with the foliar spray.     

Grain yield,zinc efficiency and zinc concentration of wheat cultivars grown in a zinc-deficient calcareous soil in field and greenhouse

Field experiments were carried out to study grain yield, zinc (Zn) efficiency and concentrations of Zn in shoot and grain of 37 bread wheat (Triticum aestivum) and three durum wheat (Triticum durum) cultivars grown in a Zn-deficient calcareous soil with (23 kg Zn ha⁻¹), and without, Zn fertilization in 1993–1994 and 1994–1995. The same Zn-deficient soil was used in greenhouse experiments to study shoot dry weight, Zn efficiency and shoot Zn concentrations of 21 bread and three durum wheat cultivars (same cultivars used in the field experiments). Zinc fertilization of cultivars in the field enhanced grain yield on average by 30% in both years. Increases in grain yield to Zn fertilization varied substantially between cultivars from 8% to 76%. Accordingly, there was large variability in Zn efficiency of cultivars, expressed as the ratio of grain yield or shoot dry-matter yield produced under Zn deficiency compared to that under Zn fertilization. On average, Zn efficiency values ranged from 57% to 92% for grain yield in field experiments and from 47% to 83% for shoot dry weight in greenhouse experiments. Most of the cultivars behaved similarly in their response to Zn deficiency in the field and greenhouse. The cultivars selected from local landraces had both, a high Zn efficiency and high yield under Zn-deficient conditions. The bread wheat cultivars, improved for irrigated conditions, had generally low Zn efficiency and low yield, both in the field and greenhouse. All durum wheat cultivars in this study also showed low levels of Zn efficiency, grain yield and shoot dry weight under Zn deficiency. Overall, there was no relation between Zn efficiency values and Zn concentrations in grain or shoot dry matter. The results presented here demonstrate the existence of substantial variation in Zn efficiency among wheat cultivars, particularly bread wheat cultivars, and suggest that wheat landrace populations are a valuable source of genes to improve high Zn efficiency of wheat for Zn-deficient soils.     

Use of tetrahymena pyriformis to evaluate the relative nutritive value (RNV) of some crop cultivars and processed cereals

Tetrahymena pyriformis was used to compare the relative nutritive value (RNV) of various components of wheat and rye bread. Rye bread crumbs were superior to those of wheat crumbs. The crust of both breads had considerably reduced RNV. When applied as an intervarietal screening tool in barley, this organism failed to detect small differences in the lysine content. Gross differences among various cereals and legumes could be detected. A colorimetric method for biomass measurement was compared with the direct microscope counting and found to be superior. The merits and limitations ofT. pyriformis as a test organism in the RNV determination are discussed.     

Genetic and Agronomic Variation in Arabinoxylan and Ferulic Acid Contents of Durum Wheat (Triticum durumL.) Grain and Its Milling Fractions

Total arabinoxylan (AXt), water-extractable arabinoxylan (WeAX) and ferulic acid (FA) from five cultivars of durum wheat (Triticum durumL.), grown under four different agronomic conditions, were measured. Among the varieties analysed, AXt, WeAX and FA contents ranged between 4·07%–6·02%, 0·37%–0·56% and 0·784 mg/g–7·98 mg/g, respectively. High genetic and agronomic variability was detected for AXt, WeAX and FA. AXt and FA increased sharply in milling products for extraction rates above 60%. FA was quantified in durum wheat milling fractions. High concentrations of FA esterified to cell-wall arabinoxylans were found in the aleurone layer (69% of total FA), germ and seedcoat (26·6% of total FA). Only trace amounts were detected in the starchy endosperm (1·4% of total FA). A highly significant correlation appeared between AXt and FA contents.     

Glutenin subunit compositions and breadmaking quality characteristics of synthetic hexaploid wheats derived from Triticum turgidum × Triticum tauschii (coss.) Schmal Crosses

The Glu-B1, Glu-D1 and Glu-B3 encoded glutenin subunit compositions of a population of synthetic hexaploid wheats (AABBDD, 2n=6x=42), which was random for flour protein (FP), SDS-sedimentation (SDSS), Alveograph strength (W), the tenacity/extensibility (P/G) ratio and bread loaf volume (LV) were examined in this study. The synthetics were produced from various crosses involving several Triticum lurgidum cultivars and Triticum lauschii (coss.) Schmal accessions. The Glu-A1 null allele as well as three Glu-B1 (subunits 7 + 8, 6 + 8 and 20), 13 Glu-D1 and two Glu-B3 (LMW-1 and LMW-2) allelic variants were present in the synthetic population. Thirty-six different glutenin subunit combinations, including the Glu-B1, Glu-D1 and Glu-B3 encoded alleles, were observed. The synthetic hexaploids showed large variations for all quality parameters evaluated. All quality characteristics except one (P/G ratio, which showed no association with allelic variations at Glu-B3) were influenced by allelic variations at the Glu-B1 and Glu-B3 loci; subunits 6 + 8 and 7 + 8 showed significantly better quality effects than subunit 20. Low M_r glutenin subunits LMW-1 and LMW-2 showed both negative and positive quality effects. The Glu-D1 locus of T. tauschii contributed various alleles not found in bread wheat. The influence of new Glu-D1 alleles on the bread-making quality characteristics of the synthetic wheats could not be established, partly because there was a limited frequency of some of the alleles in the population, and partly because some synthetics, having a common Glu-D1 allele, showed quality differences associated with allelic variation at Glu-B1 and/or Glu-B3. Differential quality effects could be observed, however, among some Glu-D1 alleles. Synthetics derived from a common durum wheat source showed better overall quality characteristics and bread loaf volume when they possessed subunits 5 + 12 or 1·5 + 10 than when they had any other Glu-D1 encoded glutenin subunit.     

Influence of Non-Starch Polysaccharides Structure on the Metabolisable Energy of U.K. Wheat Fed to Poultry

With the inclusion of wheat in European poultry diets at 600 g/kg, or more, there is increasing concern that its apparent metabolisable energy (AME) is more variable than would be predicted by conventional analysis. Twelve samples of wheat with a range of AME values (8·34–13·74 MJ/kg dry matter when fed to broiler chicks aged 11–14 d at 750 g/kg diet) were used to investigate the causes of this variability. AME was not correlated with the amount of total water-soluble non-starch polysaccharide (sNSP), soluble arabinoxylan (the major polysaccharide contributing to NSP) or (1→3, 1→4)-β-glucan released from the grain or with the viscosity of aqueous extracts. Surprisingly,in vitroviscosity was negatively related to soluble (r²=0·61) and total (r²=0·82) arabinoxylan. This was thought to be due to the slow, but cumulative, action of endogenous hydrolases in the stored grain. Soluble NSP from each wheat was characterised by measurement of molecular weight distribution and the structural features of arabinoxylan determined from the amount and nature of the oligosaccharides released following treatment with an endo-xylanase. Oligomer molecular weight was determined by matrix-assisted laser desorption/ionisation time of flight mass spectrometry and structure by NMR. Multivariate analysis of the 32 variables measured provided a three-term model able to explain approximately 0·80 of the variation between wheat samples: AME=8·07+11·16(XRAX)+30·67(AX-6)−0·355(sNSP) Two terms (XRAX, the proportion of arabinoxylan resistant to hydrolysis by xylanase and AX-6, the properties of branched six-sugar present in hydrolysates) reflected the degree of branching of arabinoxylan and were positively associated with AME while the third term, the amount of sNSP present, was negatively related.     

Effect of the grain protein content locus Gpc-B1 on bread and pasta quality

Grain protein concentration (GPC) affects wheat nutritional value and several critical parameters for bread and pasta quality. A gene designated Gpc-B1, which is not functional in common and durum wheat cultivars, was recently identified in Triticum turgidum ssp. dicoccoides. The functional allele of Gpc-B1 improves nitrogen remobilization from the straw increasing GPC, but also shortens the grain filling period resulting in reduced grain weight in some genetic backgrounds. We developed isogenic lines for the Gpc-B1 introgression in six hexaploid and two tetraploid wheat genotypes to evaluate its effects on bread-making and pasta quality. In common wheat, the functional Gpc-B1 introgression was associated with significantly higher GPC, water absorption, mixing time and loaf volume, whereas in durum wheat, the introgression resulted in significant increases in GPC, wet gluten, mixing time, and spaghetti firmness, as well as a decrease in cooking loss. On the negative side, the functional Gpc-B1 introgression was associated in some varieties with a significant reduction in grain weight, test weight, and flour yield and significant increases in ash concentration. Significant gene × environment and gene × genotype interactions for most traits stress the need for evaluating the effect of this introgression in particular genotypes and environments.     

Effect of incorporation of an i-type low-molecular-weight glutenin subunit and a modified γ-gliadin in durum and in bread wheat doughs as measured by micro-mixographic analyses

The effects of incorporation of an i-type low-molecular-weight glutenin subunit (LMW-i) and of a modified γ-gliadin showing an additional cysteine residue, on 2 g Mixograph parameters of durum (biotypes 42 and 45 of the Italian cv. Lira) and bread wheat (Australian cv. Kukri) doughs were studied. In bread wheat flour incorporation of the modified γ-gliadin resulted in a significant decrease in dough strength (decreased mixing time and peak resistance), but at the same time it produced a slight increase in dough stability (decreased resistance to breakdown). The incorporation of the LMW-i type into bread wheat dough had minimal effects on dough mixing requirements. The incorporation of both LMW-i type and modified γ-gliadin in durum wheat doughs produced a significant decrease in the overall dough strength, especially in Lira 45 biotype doughs. Reversed phase high-performance liquid chromatography (RP-HPLC), size exclusion high-performance liquid chromatography (SE-HPLC) and two-dimensional gels analyses of control and reconstituted semolina doughs showed that the two polypeptides were in the polymeric fraction. The effect of the incorporation of the two polypeptides in durum and bread wheat doughs showed remarkable differences and the reasons for this is discussed in terms of both intrinsic differences between wheat flour and durum semolina and in methodological approaches.     

Tiller traits of spring cereals under tiller-depressing long day conditions

Long days partially depress tiller growth of spring cereals. In this study we characterised and quantified growing conditions and cultivar-induced variation in tiller traits and contribution of tillers to grain yield. Experiments were done at two locations in southern Finland, incorporating two nitrogen fertiliser application rates (80 and 120 kg N ha⁻¹) and 12 two-row barley (Hordeum vulgare L.), 10 six-row barley, ten oat (Avena sativa L.) and 11 wheat (Triticum aestivum L.) cultivars. Spring cereal species differed significantly in their tillering: two-row barley was superior compared with other spring cereals, with the highest number and growth capacity of tillers and head-bearing tillers. Grain yield produced by tillers was, however, always modest compared with that of main shoots, ranging from 13% and 15% in oat and wheat to 20% in six-row barley and 64% in two-row barley. Cultivar and growing condition-induced differences were marked in tiller traits, but tillers were never able to out-yield the main shoot. This is likely to be emphasised by standard use of high seeding rates. Tillers are dominated by the main shoot under long day conditions at high latitudes, and tiller yield potential remains clearly underutilised even under conditions favouring growth.