Hard Winter Research Articles

Genotyping of U.S. Wheat Germplasm for Presence of Stem Rust Resistance Genes Sr24, Sr36 and Sr1RSAmigo

The stem rust resistance genes Sr24, Sr26, Sr36, and Sr1RSAmigo confer resistance to race TTKSK (= Ug99) of Puccinia graminis f. sp. tritici Pers. (Pgt). A collection of 776 cultivars and breeding lines of wheat (Triticum aestivum L.) from all growing regions of the United States were screened with simple sequence repeat and sequence tagged site markers linked to Sr24, Sr26, Sr36, and Sr1RSAmigo to determine frequencies of these genes in U.S. wheat germplasm. Marker efficacy in predicting the presence of these genes was evaluated via comparison with assayed seedling infection type. Among the lines evaluated, the most predominant gene is Sr24, present in hard winter, hard spring, and soft winter wheat lines. Resistance in soft winter wheat is primarily due to Sr36 The 1RS·1AL rye translocation carrying Sr1RSAmigo is present at equal frequencies in hard winter and soft winter wheat. Utilization of marker‐assisted selection for stem rust resistance genes can hasten the development of wheat cultivars resistant to TTKSK and its variants and allow for the development of resistance gene pyramids for more durable stem rust resistance.

Grain Yield Performance and Stability of Cultivar Blends vs. Component Cultivars of Hard Winter Wheat in Nebraska

In diverse growing environments, cultivar blends of hard winter wheat (Triticum aestivum L.) are considered as an option over pure cultivars for maintaining grain yield and reducing risk to producers. The objectives of this research were to evaluate the grain yield between blends and their component cultivars over several locations in Nebraska and to compare blend grain yield stability. Two separate experiments of six three‐cultivar blends and their component cultivars tested in a total of 30 environments and three two‐cultivar blends and their component cultivars tested in a total of 20 environments were grown in replicated randomized block designs. All component cultivars and cultivar blends (referred to as lines, hereafter) were evaluated for mean grain yield performance and stability. ‘Pronghorn’‐‘Goodstreak’‐‘Buckskin’ was the sole cultivar blend that significantly increased grain yield when compared with the average of its component cultivars. The grain yield advantage for the mean average cultivar blends varied from 2.2% lower to 1.9% higher with overall advantage of 0.4% yield increase for all the nine cultivar blends. Cultivar blends of ‘Millennium’‐‘Wesley’‐‘Wahoo’, Millennium‐‘Halt’‐Wahoo, and Millennium‐‘Alliance’‐Wahoo were the most stable lines using regression estimates for stability. When compared with the average of component cultivars, cultivar blends were more stable over different environments with little or no reduction in grain yield.

Sensitivity of Winter Wheat Cultivars to Selected Herbicides

Sensitivity of Winter Wheat Cultivars to Selected HerbicidesThe experiments on tolerance of winter wheat cultivars to herbicides were performed under field conditions during 2003-2005 in the region of Wrocław (South-West of Poland). Five cultivars were examined (Zyta, Tonacja, Sukces, Clever, Kobra). Two herbicide mixtures: isoproturon + pendimethalin and diflufenican + flurtamon were applied in the autumn, in stage of 3-4 leaves. In the spring, when wheat reached stage of full tillering, the following herbicides were used: florasulam + 2.4-D and fluroxypyr + 2.4-D. Phytotoxicity of herbicides was determined on the base of plants vigour assessment, plants counting, yield and some yield components. During the experimental period, impact of the mixture pendimethalin + isoproturon on grain yield of Clever cultivar was observed only in the season with hard winter conditions (2002/2003). The remaining varieties: Zyta, Tonacja, Sukces and Kobra were completely tolerant to this herbicide mixture. Mild winter seasons did not show a negative influence of herbicides on grain yield of tested varieties. All cultivars showed a complete tolerance to diflufenican + flurfamon and florasulam + 2.4-D. The mixture fluroxypyr + 2.4-D caused ear deformation of all tested wheat cultivars, but did not affect negatively grain yield.

RED FLAT BARK LARVAE VITRIFY TO SURVIVE –150°C

When the long hard northern winter sets in, insect larvae have two options: beat the ice or perish. Some insects tolerate ice formation while others avoid freezing and cheat death by stuffing themselves full of antifreeze compounds. However, insects that live in the extreme latitudes may have to go to even greater lengths to survive; their supercooled body fluids may transform into a viscous glass (vitrify) at extremely low temperatures to avoid freezing. Todd Sformo and colleagues from the University of Alaska Fairbanks, the University of Notre Dame and 21st Century Medicine, Inc., explain that larvae from some Alaskan populations of the red flat bark beetle seem to remain unfrozen at temperatures as low as –80°C, and they wondered whether the larvae may have opted for the vitrification option. Curious to find out how overwintering larvae survive, Sformo and his colleagues measured the antifreeze protein activity, water and glycerol contents as well as the change in heat capacity of the larvae's bodies as they cooled to find out if their body fluids were transformed into a glass (p. 502).Amazingly, the larvae did not freeze, even at temperatures as low as –150°C; instead of forming ice crystals, their body fluids vitrified to protect them from damage. They also found that the larvae lost body fluids as the temperature fell, increasing their glycerol levels to an impressive 4–6 mol l–1.The team explains that as summer turns into autumn the larvae begin producing antifreeze proteins to protect them down to –20°C, before beginning to dehydrate, which raises their glycerol and antifreeze concentrations even further for protection down to –40°C. Finally, as the winter temperatures fall even further, they lose more body fluids, raising their glycerol concentrations to such an extent that their body fluids turn into a viscous glass at –58°C, protecting them all the way down to –150°C.

Molecular Mapping of Wheat Leaf Rust Resistance Gene Lr42

ABSTRACTLeaf rust, caused by Puccinia triticina Eriks., is an important foliar disease of wheat (Triticum aestivum L.) worldwide. Leaf rust resistance gene Lr42 from Aegilops tauschii Coss. has been used as a source of rust resistance in breeding programs. To identify molecular markers closely linked to Lr42, a segregating population of near‐isogenic lines contrasting for the presence of Lr42 was developed in the hard winter wheat cultivar Century background and evaluated for rust infection type at both seedling and adult‐plant stages. Simple sequence repeat (SSR) markers were screened using bulked‐segregant analysis. Two markers closely linked to Lr42 were identified on chromosome 1DS. The closest marker, Xwmc432, is about 0.8 cM from Lr42. Physical mapping of both SSR markers using Chinese Spring nullitetrasomic and ditelosomic genetic stocks confirmed that the markers linked to Lr42 were on 1DS. Markers for Lr42 were highly polymorphic between parents and among a diverse set of wheat germplasm collected from several countries, indicating that these markers are useful for marker‐assisted selection for Lr42.

Multifractal spectrum analysis of nonlinear dynamical mechanisms in China’s agricultural futures markets

Based on Partition Function and Multifractal Spectrum Analysis, we investigated the nonlinear dynamical mechanisms in China’s agricultural futures markets, namely, Dalian Commodity Exchange (DCE for short) and Zhengzhou Commodity Exchange (ZCE for short), where nearly all agricultural futures contracts are traded in the two markets. Firstly, we found nontrivial multifractal spectra, which are the empirical evidence of the existence of multifractal features, in 4 representative futures markets in China, that is, Hard Winter wheat (HW for short) and Strong Gluten wheat (SG for short) futures markets from ZCE and Soy Meal (SM for short) futures and Soy Bean No.1 (SB for short) futures markets from DCE. Secondly, by shuffling the original time series, we destroyed the underlying nonlinear temporal correlation; thus, we identified that long-range correlation mechanism constitutes major contributions in the formation in the multifractals of the markets. Thirdly, by tracking the evolution of left- and right-half spectra, we found that there exist critical points, between which there are different behaviors, in the left-half spectra for large price fluctuations; but for the right-hand spectra for small price fluctuations, the width of those increases slowly as the delay t increases in the long run. Finally, the dynamics of large fluctuations is significantly different from that of the small ones, which implies that there exist different underlying mechanisms in the formation of multifractality in the markets. Our main contributions focus on that we not only provided empirical evidence of the existence of multifractal features in China agricultural commodity futures markets; but also we pioneered in investigating the sources of the multifractality in China’s agricultural futures markets in current literature; furthermore, we investigated the nonlinear dynamical mechanisms based on spectrum analysis, which offers us insights into the underlying dynamical mechanisms in China’s agricultural futures markets.

Cuticular proteins and seasonal photoperiodism in aphids

For poikilotherm animals such as insects, extreme temperatures can be a severe issue in continental regions. Aphids, which reproduce in spring and summer by viviparity, are prone to death in hard winter conditions. These species exhibit reproductive plasticity adapted to winter by producing oviparous females in autumn, which lay overwintering eggs. This switch is driven by photoperiodism, and long nights are sufficient to trigger the change in reproductive mode. Global transcriptomic analyses applied to the pea aphid Acyrthosiphon pisum for which genomic resources are now available have allowed the identification of several genetic programs regulated by photoperiod shortening. Unexpectedly, one of these genetic programs concerns cuticle proteins and cuticle structure. This opens new tracks for investigations and poses new hypotheses on the link between cuticle modification and neuronal signalisation of photoperiod in aphids in response to seasonal photoperiodism. This review focuses on the description of cuticular protein genes in the pea aphid and their regulation during the change of reproductive mode.

ALKALINE NOODLES AND FLOUR/GEL PROPERTIES OF HARD RED AND WHITE WINTER WHEAT

ABSTRACT Alkaline noodle characteristics and flour gel properties made with one white and one red hard winter wheat cultivar were studied. The wheat was grown in four Oklahoma agricultural districts, with two to seven locations on each district. Both cultivars had similar flour protein content and overall raw dough sheet color stability (ΔL* andΔb*) in three out of four agricultural districts. Cimarron and Oro Blanco showed differences inΔa*,Δb* and adhesiveness in the North Central agricultural district. Resilience values of cooked noodles from Oro Blanco were small, but significantly higher in the Central district. Higher flour peak viscosity was observed for Oro Blanco, plus a trend to lower polyphenol oxidase activity and higher elastic modulus than Cimarron.PRACTICAL APPLICATIONSHard red winter wheat from the U.S.A. is used in the manufacturing of alkaline noodles in Asia. Color and texture characteristics are among the most important attributes that determine the quality of this type of noodles. Two types of winter wheat cultivars, red and white, were compared and their key properties (including gel properties) of importance in the international trade and noodle manufacturing are reported.

Molecular Mapping of Stem‐Rust‐Resistance Gene Sr40 in Wheat

ABSTRACTStem rust, caused by Puccinia graminis f. sp. tritici, was historically one of the most destructive diseases of wheat (Triticum aestivum L.) worldwide. Deployment of resistant cultivars successfully prevented rust epidemics over the past several decades. Unfortunately, race TTKS (termed Ug99) has emerged in Africa to render several stem‐rust‐resistance genes ineffective. Sr40, a stem‐rust‐resistance gene from Triticum timopheevii ssp. armeniacum, was transferred to wheat on translocation chromosome T2BL/2G#2S and provides effective levels of seedling and adult plant resistance against Ug99. Two mapping populations were developed using Ug99‐resistant line RL6088 and moderately susceptible to susceptible hard winter wheat cultivars Lakin and 2174. The parents were screened with 83 simple sequence repeats (SSR) from chromosome 2B and the polymorphic markers were analyzed on F2 populations. F2 and F2:3 populations were inoculated with North American stem rust race RKQQ at the seedling stage. Marker locus Xwmc344 was most closely linked to Sr40 (0.7 cM) in the RL6088/Lakin linkage map, followed by Xwmc474 and Xgwm374 Marker locus Xwmc474 was mapped ∼2.5 cM proximal to Sr40 in the RL6088/2174 population. Xwmc474 and Xwmc661 flanked Sr40 in both populations. Markers linked to Sr40 will be useful for marker‐assisted integration and pyramiding of Sr40 into elite wheat breeding lines, and reduction in the size of the T. timopheevii segment harboring this gene.

A Comprehensive Genotype and Environment Assessment of Wheat Grain Ash Content in Oregon and Washington: Analysis of Variation

ABSTRACTA comprehensive analysis of the variation in wheat grain ash content has not been previously conducted. This study assessed the relative contribution of genotype and environment to variation in ash content, with a particular aim of ascertaining the potential for manipulating the trait using contemporary adapted germplasm. A total of 2,240 samples were drawn from four years of multilocation field plots grown in the wheat production areas of Oregon and Washington states. Genotypes included commercial cultivars and advanced breeding lines of soft and hard winter, and soft and hard spring wheats with red and white kernel color, several soft white club wheats, and one soft white spring waxy wheat cultivar. In addition to ash, protein content, test weight, and Single Kernel Characterization System kernel hardness, weight and size were also measured. In total, 20 separate fully balanced ANOVA results were conducted. Whole model R2 values were highly significant, 0.62–0.91. Nineteen of the 20 ANOVA results indicated significant genotype effects, but the effects were not large. In contrast, environment effects were always highly significant with F values often one to two orders of magnitude larger than the genotype F values. The grand mean for all samples was 1.368% ash. For individual data sets, genotype means across environments varied ≈0.1–0.3% ash. The genotypes judged noteworthy because they had the highest least squares mean ash content were OR9900553 and ClearFirst soft white winter, NuHills hard red winter, Waxy‐Pen and Cataldo soft white spring, and WA8010 and Lochsa hard spring wheats. Genotypes with lowest least squares mean ash were Edwin (club) soft white winter, OR2040073H hard red winter, WA7952 soft white spring, and WA8038 hard spring wheats. In conclusion, wheat grain ash is more greatly influenced by crop year and location than by genotype. However, sufficient genotype variation is present to plausibly manipulate this grain trait through traditional plant breeding.

In Vitro Bile‐Acid‐Binding of Whole vs. Pearled Wheat Grain

ABSTRACTHealth benefits of consuming whole grains are reduced risk of heart disease, stroke, and cancer. The U.S. Health and Human Services and USDA dietary guidelines recommend consumption of 6–10 oz of grain products daily and one‐half of that amount should contain whole grains. Whole grains contain vitamins, minerals, fiber, and phytonutrients. Bile‐acid‐binding capacity has been related to cholesterol lowering potential of food fractions. Lowered recirculating bile acids results in utilization of cholesterol to synthesize bile acid and reduced fat absorption. Secondary bile acids have been associated with increased risk of cancer. Bile‐acid‐binding potential has been related to lowering the risk of heart disease and that of cancer. It has been reported that bile‐acid‐binding of wheat bran is not related to its total dietary fiber (TDF) content. Whole (W) grain as well as pearled (P) hard red winter wheat (Hrw), hard white winter wheat (Hww), and durum wheat (DU) cooked grains were evaluated for in vitro, bile‐acid‐binding relative to cholestryramine (a cholesterol lowering bile‐acid‐binding drug). On dry matter basis (db) relative bile‐acid‐binding values were 7.7% WHrw; 7.5% WHww; 6.3% PHww; 6.0% PHrw; 5.5% WDU; and 5.4% PDU. On a TDF basis, binding values were 42–57% of that for cholestyramine for the whole and pearled wheat grains tested. Bile‐acid‐binding values (db) for WHrw and WHww were similar and significantly higher than those of PHww, PHrw, WDU and PDU. Similar bile‐acid‐binding of WHww to that of WHrw suggest that the red color commonly associated with whole grain may not necessarily indicate more healthful potential. Data suggest that cooked WHrw and WHww wheat have significantly higher health‐promoting potential than pearled grains. WDU or PDU wheat health‐promoting potential was similar to that of PHww or PHrw. Consumption of products containing WHrw and WHww are recommended.

Registration of ‘Thunder CL’ Wheat

‘Thunder CL’ (Reg. No. CV‐1031, PI 655528) hard white winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in August 2008 through a marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorado State University (CSU), USDA–ARS researchers at Manhattan, KS, St. Paul, MN, and Pullman, WA, participated in the development of Thunder CL. Thunder CL was selected from the cross KS01‐5539/CO99W165 made in 2000 at Fort Collins, CO. KS01‐5539 is an unreleased experimental line from Kansas State University with the pedigree FS2/KS97HW150//KS97HW349, and CO99W165 is an unreleased experimental line from CSU with the pedigree KS92WGRC25/‘Halt’. Thunder CL was derived from a population advanced from the F2 to F4 by single‐seed descent. Thunder CL was selected as an F4:5 line in September 2003 and assigned experimental line number CO03W239. Thunder CL was released because of its superior grain yield under nonirrigated and irrigated production conditions in eastern Colorado, it carries the Als1 gene for tolerance to imazamox herbicide, it is moderately resistant to wheat streak mosaic virus, stripe rust (Puccinia striiformis f. sp. tritici), and stem rust (P. graminis f. sp. tritici), and it has superior milling and bread baking quality.

Echinococcus granulosus Infection and Options for Control of Cystic Echinococcosis in Tibetan Communities of Western Sichuan Province, China

BackgroundHuman cystic echinococcosis (CE) is highly endemic in the Tibetan regions of Sichuan where most families keep guard dogs and where there are considerable numbers of ownerless/stray dogs. Strong Buddhist beliefs do not allow for elimination of stray dogs, and many strays are actually fed and adopted by households or monasteries. On account of the high altitude (3900–5000 m), pasturage is the major agricultural activity in this area. The harsh mountainous climate often leads to many grazing animals dying on the pasture at the end of a hard winter. The skin and some meat are taken, and the rest of the animal is left for scavenging birds and animals. The poor sanitation and hygiene, the Buddhist doctrine of allowing old livestock to die naturally, plus the unrestricted disposal of animal viscera post-slaughter may be responsible for the high prevalence of human CE in this setting.Methods and FindingsAs part of a large collaborative control program for CE in Ganzi County, situated in the west of Sichuan Province, surveillance for Echinococcus infection in domestic dogs using a coproantigen method and necropsy of unwanted dogs was carried out prior to (in 2000) and after (in 2005) dog anthelminthic treatment (5 mg/kg oral praziquantal at 6 month intervals) to determine the efficacy of the treatment for control. The prevalence of E. granulosus only in dogs by necropsy was 27% and 22%, and prevalence of both Echinococcus spp. by necropsy was 63% and 38%; prevalence of both Echinococcus spp. by coproantigen analysis was 50% and 17%. Necropsy of sheep/goats (age <1 to 12 years) (prevalence of E. granulosus in 1–6-year-old animals was 38% and in 10–12-year-old animals was 70%) and yaks (age 4 years) (prevalence of E. granulosus was 38%) was undertaken to determine the baseline transmission pressure. Protoscoleces were only found in very old sheep/goats and yaks. Necropsy of dogs in the Datangma district indicated that there was no apparent significant change in the overall prevalence of E. granulosus in unwanted dogs after 5 years of 6-month praziquantel treatment. However, this was likely due to the number of dogs available for necropsy being too small to reflect the real situation prevailing. There was a highly significant decrease in Echinococcus prevalence after the 5-year treatment program shown by coproantigen-ELISA. This indicated a decreasing but continuing risk for re-infection of domestic and stray dogs. Genotyping of E. granulosus samples obtained from necropsied sheep/goats and yaks and from locally infected humans at surgery was carried out to determine the strain of parasite responsible for human infection. DNA genotyping indicated that only the sheep strain (G1) of E. granulosus was present in the study area.ConclusionsConsiderable re-infection rates of E. granulosus among dogs indicated a high infection pressure from infected livestock in this region, most likely from older animals dying on the pasture. A combination of livestock vaccination with the Eg95 vaccine, which is effective against the sheep strain of E. granulosus, and dog anthelmintic treatment, thus targeting two critical points of the parasite life-cycle, would avoid the conflicts of religion or local culture and could achieve the goal of hydatid control in the long term.

Genetic characterization of powdery mildew resistance in U.S. hard winter wheat

Powdery mildew significantly affects grain yield and end-use quality of winter wheat in the southern Great Plains. Employing resistance resources in locally adapted cultivars is the most effective means to control powdery mildew. Two types of powdery mildew resistance exist in wheat cultivars, i.e., qualitative and quantitative. Qualitative resistance is controlled by major genes, is race-specific, is not durable, and is effective in seedlings and in adult plants. Quantitative resistance is controlled by minor genes, is non-race-specific, is durable, and is predominantly effective in adult plants. In this study, we found that the segregation of powdery mildew resistance in a population of recombinant inbred lines developed from a cross between the susceptible cultivar Jagger and the resistant cultivar 2174 was controlled by a major QTL on the short arm of chromosome 1A and modified by four minor QTLs on chromosomes 1B, 3B, 4A, and 6D. The major QTL was mapped to the genomic region where the Pm3 gene resides. Using specific PCR markers for seven Pm3 alleles, 2174 was found to carry the Pm3a allele. Pm3a explained 61% of the total phenotypic variation in disease reaction observed among seedlings inoculated in the greenhouse and adult plants grown in the field and subjected to natural disease pressure. The resistant Pm3a allele was present among 4 of 31 cultivars currently being produced in the southern Great Plains. The genetic effects of several minor loci varied with different developmental stages and environments. Molecular markers associated with these genetic loci would facilitate incorporating genetic resistance to powdery mildew into improved winter wheat cultivars.

Genetic loci in the photoperiod pathway interactively modulate reproductive development of winter wheat

Responses to photoperiod and low temperature are the two primary adaptive mechanisms which enable wheat plants to synchronize developmental processes with changes in seasonal climate. In this study, the developmental process was characterized at two stages: stem length during the onset of stem elongation and heading date. These two developmental events were monitored and mapped in recombinant inbred lines (RILs) of a population generated from a cross between two complementary and locally adapted hard winter wheat cultivars. 'Intrada' undergoes stem elongation earlier but reaches heading later, whereas 'Cimarron' undergoes stem elongation later but reaches heading earlier. Variation in the developmental process in this population was associated with three major QTLs centered on Xbarc200 on chromosome 2B, PPD-D1 on chromosome 2D, and Xcfd14 on chromosome 7D. The Intrada Xbarc200 and Xcfd14 alleles and the Cimarron PPD-D1 allele accelerated both stem elongation and heading stages, or the Cimarron Xbarc200 and Xcfd14 alleles and the Intrada PPD-D1 allele delayed both stem elongation and heading stages. Integrative effects of the three QTLs accounted for 43% (initial stem length) and 68% (heading date) of the overall phenotypic variation in this population. PPD-D1 is a reasonable candidate gene for the QTL on chromosome 2D, PPD-B1 could be associated with the QTL on chromosome 2B, but VRN-D3 (=FT-D1) was not linked with the QTL on chromosome 7D, suggesting that this is a novel locus involved in winter wheat development. Because the PPD-D1 QTL was observed to interact with other two QTLs, all of these QTLs could play a role in the same pathway as involved in photoperiod response of winter wheat.

Bubbles in Commodities Markets

We investigate the presence of rational speculative bubbles in 28 commodities traded in the U.S. markets. Using the duration dependence test on the stochastic interest-adjusted basis, we find that 11 of 28 commodities experienced some episodes of rational speculative bubble. These commodities are in the energy sector WTI crude oil; in foodstuffs and industrials sector coffee; in livestock and meats sector lean hogs; and in metals gold and platinum. In the grains and oilseeds sector corn, the soybean sub-sector (soybean No. 2, soybean meal and oil) and the wheat sub-sector, (wheat No. 2 soft red and hard winter) all exhibited speculative bubbles. Additionally, we report mean reversion in natural gas, propane, live cattle, and pork bellies.

Differential responses of two types of winter wheat ( Triticum aestivum L.) to autumn- and spring-applied mesosulfuron-methyl

Field experiments were conducted in the 2005/2006 and 2006/2007 crop seasons to evaluate the tolerance of hard winter wheat (HWW) and soft winter wheat (SWW) varieties to post-emergence mesosulfuron-methyl treatment. The application of mesosulfuron-methyl at 11.25 g a.i. ha −1 plus a noninonic surfactant at 252 g a.i. ha −1 to three HWW and three SWW varieties in either autumn (Zadoks stage 14–15) or spring (Zadoks stage 24–25) resulted in visible injury, including chlorisis, stunting and leaf deformities. The greatest injury occurred at fourteen days after treatment (DAT) for all wheat varieties. All varieties showed the same initial sensitivity to herbicide treatment, but differed significantly in their recovery from plant damages. The HWW varieties recovered more successfully from spring-applied herbicide than the SWW varieties; conversely, the SWW varieties recovered more rapidly from damage caused by autumn-applied herbicide than the HWW varieties. Normalized Difference Vegetative Index (NDVI) values were severely affected by autumn herbicide application for HWW varieties and spring application for SWW varieties. Autumn herbicide application for SWW varieties and spring herbicide application for HWW varieties produced higher grain yields. Based on these data, we conclude that applying mesosulfuron-methyl plus a noninonic surfactant in autumn for SWW varieties and in spring for HWW varieties is optimal, and that application timing has profound implications for herbicide tolerance and production of wheat.

Effects of Baking Conditions, Dough Fermentation, and Bran Particle Size on Antioxidant Properties of Whole-Wheat Pizza Crusts

This study investigated the effects of processing conditions including bran particle size, dough fermentation time, and baking time and temperature on the extractable antioxidant properties of whole-wheat pizza crust. Experiments were carried out using two different varieties of hard white winter wheat, Trego and Lakin. Antioxidant properties examined included oxygen radical absorbing capacity (ORAC), hydroxyl radical scavenging capacity (HOSC), relative 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity (RDSC), cation 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging capacity, total phenolic contents (TPC), and ferulic acid contents. Results indicated that bran particle size had no effect on the antioxidant properties evaluated. Increasing dough fermentation time from 0 to 48 h had no significant influence on antioxidant properties except HOSC, which increased as much as 28%, possibly as a result of increase in soluble free ferulic acid, which increased as much as 130%. Increasing baking temperature from 204 to 288 degrees C with a 7 min bake time increased all evaluated antioxidant properties by as much as 82%. Increasing baking time from 7 to 14 min with 204 degrees C baking temperature might increase some antioxidant properties as much as 60%. The results from this study suggest that longer dough fermentation times and increased baking time or temperature may be potential approaches to increase the antioxidant availability in whole-wheat pizza crust.

Genotype and Environment Variation for Arabinoxylans in Hard Winter and Spring Wheats of the U.S. Pacific Northwest

ABSTRACTThe development of high‐quality wheat (Triticum aestivum L.) cultivars depends on a thorough understanding of the constituents of grain and their variation due to genetics and environment. Arabinoxylans (pentosans) are key constituents of wheat grain and have broad and far‐reaching influences on milling and baking quality. However, variation in arabinoxylans due to genotype and environment are not fully understood. In this study, 25 hard winter and 25 hard spring wheat commercial cultivars and advanced breeding lines developed from eight public and private breeding programs in the U.S. Pacific Northwest were analyzed for water‐extractable and total arabinoxylan contents (WE‐AX and total AX), and the proportion of total AX that was water‐extractable. Winter and spring genotypes were grown in three environments each. The results indicated that there were significant differences among both sets of hard wheat genotypes for WE‐AX, total AX, and proportion of total AX that was WE‐AX. The WE‐AX and total AX mean content ranges for the winter cultivars were 0.390–0.808 and 3.09–4.04%, respectively; and for the spring cultivars 0.476–0.919 and 3.94–4.70%, respectively. WE‐AX as a percentage of total AX was similar between the two genotype sets, 11.7–23.0%. Arabinoxylan fractions were generally not correlated with grain protein, test weight, and kernel hardness. The two highest correlations for winter wheats were between protein and total AX (r = –0.40) and test weight and percentage of total AX that were water‐extractable (r = 0.37) for winter wheats. Among spring wheats, single‐kernel characterization system hardness was negatively correlated with WE‐AX and proportion of total AX that was WE‐AX (r = –0.46 and –0.51, respectively). Although often significant, arabinoxylan fractions were usually not highly intercorrelated, indicating some independence of traits. Notable genotypes, being especially high or low for one or more arabinoxylan fraction and, thus, candidates for further genetic study and cross‐breeding, included Juniper, Eddy, and ORN980995 winter wheats, and Hollis, Alta Blanca, and WQL9HDALP spring wheats. Although the results indicate that arabinoxylan fractions of wheat grain can be highly influenced by environment, there is clear support for the existence of genetic differences, especially for WE‐AX and the proportion of total AX that is water‐extractable. As such, the manipulation of arabinoxylan content of wheat grain seems to be a reasonable breeding objective.

Molecular markers for wheat leaf rust resistance gene Lr41

Leaf rust, caused by Puccinia triticina Eriks., is an important foliar disease of common wheat (Triticum aestivum L.) worldwide. Pyramiding several major rust-resistance genes into one adapted cultivar is one strategy for obtaining more durable resistance. Molecular markers linked to these genes are essential tools for gene pyramiding. The rust-resistance gene Lr41 from T. tauschii has been introgressed into chromosome 2D of several wheat cultivars that are currently under commercial production. To discover molecular markers closely linked to Lr41, a set of near- isogenic lines (NILs) of the hard winter wheat cultivar Century were developed through backcrossing. A population of 95 BC3F2:6 NILs were evaluated for leaf rust resistance at both seedling and adult plant stages and analyzed with simple sequence repeat (SSR) markers using bulked segregant analysis. Four markers closely linked to Lr41 were identified on chromosome 2DS; the closest marker, Xbarc124, was about 1 cM from Lr41. Physical mapping using Chinese Spring nullitetrasomic and ditelosomic genetic stocks con- firmed that markers linked to Lr41 were on chromosome arm 2DS. Marker analysis in a diverse set of wheat germplasm indicated that primers BARC124, GWM210, and GDM35 amplified poly- morphic bands between most resistant and susceptible accessions and can be used for marker-assisted selection in breeding programs.