The Aegilops ventricosa segment on chromosome 2AS of the wheat cultivar 'VPM1' carries the cereal cyst nematode resistance gene Cre5

Previous studies showed that the intermediate level of resistance in bread wheat line ‘VPM1’ to pathotype Ha12 of the cereal cyst nematode could be conferred by an Aegilops ventricosa‐derived gene, CreX, in chromosome arm 2AS, which also carries the rust resistance genes Yrl7, Lr37 and Sr38. Near isogenic lines (NILs) differing for the presence and absence of the Ae. ventricosa‐derived linked genes Yrl7/Lr37/Sr38 were tested with cereal cyst nematode. Lines carrying Yr17 produced significantly fewer nematode cysts than the controls. An infested soil experiment produced better differentiation among resistant and susceptible genotypes. Susceptibility of ‘Trident’ indicated that linkage between CreX and Yr17 is incomplete. Microsatellite markers did not differentiate between ‘Trident’ and CreX‐carrying genotypes. However, Xgwm636 (104) was associated with the presence of Yr17 in all six genetic backgrounds. Since none of the reported cereal cyst nematode resistance genes is located in chromosome 2AS, CreX was designated as Cre5.     

Functional Properties of Wheat Gliadins. II. Effects on Dynamic Rheological Properties of Wheat Gluten

The effects of addition of purified total gliadin and its subgroups (α-, β-, γ- and ω-gliadins) on the dynamic rheology of gluten were investigated. The frequency sweeps of gluten with added α-, β-, γ- and ω2-gliadins showed unexpected increases in the magnitude of G′ and G′′, suggesting stiffening of the native gluten. Conversely, a reduction in the magnitude of G′ and G′′ occurred upon addition of the total gliadin fraction and the ω1-gliadin, implying softening of the gluten. Addition of individual gliadin fractions increased the values of slope log G′ vs log frequency, suggesting increased concentrations of uncrossed-linked material compared with the native gluten. There were significant differences in the slope values for individual gliadin fractions. The increasing order of slopes for different gliadins was: β- >γ- >α- =ω1>ω2, indicating that glutens containing ω- and α- gliadins are relatively less crossed-linked than those containing β- and γ-gliadins. The dynamic moduli, G′ and G′′, of cv. Hereward gluten showed significant positive relationships with Mixograph parameter peak dough resistance (PDR), and loaf volume for gliadin subgroups added to cv. Hereward flour.     

Analysis of variation in growth and spline-based growth models for Marecha and Lassi dromedary camels

Tropical Animal Health and Production - Camel is an important domestic animal that is well adapted to extremely harsh environments. Due to its multi-purpose role, the camel is gaining importance,...     

Resistance in Australian barley (Hordeum vulgare) germplasm to the exotic pathogen Puccinia striiformis f. sp. hordei,causal agent of stripe rust

Eighty‐eight Australian and 10 international barley cultivars were assessed for resistance to the barley stripe (yellow) rust pathogen, Puccinia striiformis f. sp. hordei (Psh). All cultivars were tested for seedling resistance to two UK‐derived isolates of Psh (11.01 and 83.39) that were shown to differ in virulence based on responses on 16 differential barley genotypes. The 98 barley cultivars differed substantially in stripe rust response; 45% were susceptible to Psh 11.01, 53% to Psh 83.39 and 44% to both isolates. The observed diverse infection types (ITs) suggest the presence of both known and uncharacterized resistance. However, further multipathotype tests are required for accurate gene postulation. The Yerong × Franklin (Y×F) doubled haploid (DH) population was phenotypically assessed as seedlings using both Psh isolates. Yerong and Franklin were immune and highly resistant, respectively, to both isolates used in this study. Marker‐trait and QTL mapping identified a major effect on the long arm of chromosome 7H contributed by Franklin in response to all isolates. The resistance of Yerong was mapped to 113·96 and 169·38 cM on chromosome 5HL in response to Psh 11.01 and 83.39, respectively. The Psh resistance sources identified in this study can be used for further genetic analysis and introgression for varietal improvement.     

The Role of Gluten Proteins in the Baking of Arabic Bread

Fractionation and reconstitution/fortification techniques were utilised to study the role of gluten in Arabic bread. Glutens from two wheat cultivars of contrasting breadmaking quality were fractionated by dilute HCl into gliadin and glutenin. Gluten, gliadin and glutenin doughs from the good quality flour had higher G ′ and lower tan δ values than those from the poor quality flour at all the frequencies examined. Interchanging the gliadin and glutenin fractions between the reconstituted flours showed that the glutenin fraction is largely responsible for differences in the breadmaking performance. Fortification of an average quality flour with the gliadin and glutenin fractions from the poor and good quality flours, at the levels of 1% and 2% (protein to flour mass), induced marked differences in the mechanical properties of bread. The resilience of the loaves was not adversely affected by the addition of gliadins and increased, with a concomitant significant (p<0·05) improvement in quality, at the 2% level of fortification with gliadins from the good quality flour. Addition of glutenin resulted in loaves with leather-like properties that became particularly apparent at the higher level of fortification; the observed deterioration in quality paralleled the increase in the elastic character of the doughs. It is suggested that highly-elastic doughs are not compatible with the rapid expansion of gases at the high-temperature short-time conditions employed in the baking of Arabic bread and that there exists a threshold in dough elasticity beyond which a rapid decline in quality takes place.