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This study investigated the effects of different elevated CO2 concentrations [ambient CO2 concentration (CK), CK plus 40 μmol mol-1 (T1), CK plus 200 μmol mol-1 (T2)] on photosynthetic characteristics and growth of rice (Oryza sativa L.) and winter wheat (Triticum aestivum L.). The results showed that T2 treatment decreased the net photosynthetic rate and leaf nitrogen content (LNC) but increased the light-saturated net photosynthetic rate of rice. Additionally, T2 treatment increased biomass accumulation and yield in both rice and winter wheat to some extent. T1 treatment, however, had little effect on photosynthetic parameters, LNC, biomass, and yield during the rice and winter wheat growing seasons. The above results suggest that the photosynthesis and growth responses of rice and winter wheat to different CO2 concentrations differed, in general, the increase of CO2 concentrations influenced more photosynthetic performance and growth of C3 plants than lower CO2 concentrations. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of diets containing different amounts of wheat, as a partial or whole substitute for corn, on digestibility, digestive enzyme activities, serum metabolite contents and ruminal fermentation in beef cattle. Four Limousin LuXi crossbred cattle with a body weight (400±10 kg), fitted with permanent ruminal, proximal duodenal and terminal ileal cannulas, were used in a 4×4 Latin square design with four treatments: Control (100% corn), 33% wheat (33% substitution for corn), 67% wheat (67% substitution for corn), and 100% wheat (100% substitution for corn) on a dry matter basis. The results showed that replacing corn with increasing amounts of wheat increased the apparent digestibility values of dry matter, organic matter, and crude protein (p<0.05). While the apparent digestibility of acid detergent fiber and neutral detergent fiber were lower with increasing amounts of wheat. Digestive enzyme activities of lipase, protease and amylase in the duodenum were higher with increasing wheat amounts (p<0.05), and showed similar results to those for the enzymes in the ileum except for amylase. Increased substitution of wheat for corn increased the serum alanine aminotransferase concentration (p<0.05). Ruminal pH was not different between those given only corn and those given 33% wheat. Increasing the substitution of wheat for corn increased the molar proportion of acetate and tended to increase the acetate-to-propionate ratio. Cattle fed 100% wheat tended to have the lowest ruminal NH3-N concentration compared with control (p<0.05), whereas no differences were observed among the cattle fed 33% and 67% wheat. These findings indicate that wheat can be effectively used to replace corn in moderate amounts to meet the energy and fiber requirements of beef cattle. [ABSTRACT FROM AUTHOR]

The influences of differently processed wheat products on rumen fermentation, microbial populations, and serum biochemistry profiles in beef cattle were studied. Four ruminally cannulated Limousin ? Luxi beef cattle (400 ± 10 kg) were used in the experiment with a 4 4 Latin square design. The experimental diets contained (on a DM basis) 60% corn silage as a forage source and 40% concentrate with 4 differently processed wheat products (extruded, pulverized, crushed, and rolled wheat). Concentrations of ruminal NH3-N and microbial protein (MCP) in cattle fed crushed and rolled wheat were greater (P < 0.05) than the corresponding values in cattle fed pulverized and extruded wheat. Ruminal concentrations of total VFA and acetate and the ratio of acetate to propionate decreased (P < 0.05) with increased geometric mean particle size (geometric mean diameter) of processed wheat, except for extruded wheat; cattle fed extruded wheat had the lowest concentrations of total VFA and acetate among all treatments. The relative abundance of Ruminococcus flavefaciens, Prevotella ruminicola, ciliated protozoa, and Butyrivibrio fibrisolvens was lower in cattle fed the pulverized wheat diet than in the other 3 diets (P < 0.05), whereas the relative abundance of Streptococcus bovis was decreased in cattle fed extruded wheat compared with cattle fed crushed and rolled wheat (P < 0.05). No treatment effect was obtained for serum enzyme activity and protein concentration (P > 0.05). Our findings suggest that the method of wheat processing could have a significant effect on ruminal fermentation parameters and microbial populations in beef cattle and that crushed and rolled processing is better in terms of ruminal NH3-N and MCP content, acetate-to-propionate ratio, and relative abundance of rumen microorganisms. [ABSTRACT FROM AUTHOR]

The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), is a serious economic pest of wheat (Triticum aestivum L.) worldwide. Although resistant wheat cultivars provide good control of RWA, genetic characterization is critical to the continual use of aphid-resistance genes. The objective of this study was to determine the chromosome location and the genetic relationships of the RWA-resistance genes Dn1, Dn2, Dn4, Dn5, Dn6, Dnx, and several uncharacterized Dn genes. Molecular mapping demonstrated that Dn genes in four uncharacterized wheat lines (PI 47545, PI 222666, PI 222668, and PI 225245) as well as Dn1, Dn2, Dn5, Dn6, and Dnx are tightly linked to microsatellite markers Xgwm44 and Xgwm111. Deletion bin mapping assigned Xgwm44 physically in the region distal to the breakpoints 7DS-4 (FL 0.61) and Xgwm111 distal to 7DS-5 (FL 0.36) of wheat chromosome arm 7DS. Allelism tests detected no segregation for susceptibility among TC1F1 plants from the test crosses or among F2 plants derived from intercrosses between wheat lines containing each of these known Dn genes. Both marker-linkage analyses and allelism tests revealed that all these Dn genes are clustered in a region linked to Xgwm111 and are either alleles of a single locus or are closely related members of a Dn gene family. Dn4 and the uncharacterized Dn gene in PI 151918 are either allelic or linked on wheat chromosome 1DS. The linked markers and genetic relationships of these Dn genes will greatly facilitate their use in wheat breeding and the deployment of aphid-resistant cultivars. [ABSTRACT FROM AUTHOR]

The Russian wheat aphid (RWA), Diuraphis noxia Mordvilko, is a serious economic pest of wheat and barley in North America, South America, and South Africa. Using aphid-resistant cultivars has proven to be a viable tactic for RWA management. Several dominant resistance genes have been identified in wheat, Triticum aestivum, including Dn1 in PI 137739, Dn2 in PI 262660, and at least three resistance genes (Dn5+) in PI 294994. The identification of RWA-resistant genes and the development of resistant cultivars may be accelerated through the use of molecular markers. DNA of wheat from near-isogenic lines and segregating F2 populations was amplified with microsatellite primers via PCR. Results revealed that the locus for wheat microsatellite GWM111 (Xgwm111), located on wheat chromosome 7DS (short arm), is tightly linked to Dn1, Dn2 and Dn5, as well as Dnx in PI 220127. Segregation data indicate RWA resistance in wheat PI 220127 is also conferred by a single dominant resistance gene (Dnx). These results confirm that Dn1, Dn2 and Dn5 are tightly linked to each other, and provide new information about their location, being 7DS, near the centromere, instead of as previously reported on 7DL. Xgwm635 (near the distal end of 7DS) clearly marked the location of the previously suggested resistance gene in PI 294994, here designated as Dn8. Xgwm642 (located on 1DL) marked and identified another new gene Dn9, which is located in a defense gene-rich region of wheat chromosome 1DL. The locations of markers and the linked genes were confirmed by di-telosomic and nulli-tetrasomic analyses. Genetic linkage maps of the above RWA resistance genes and markers have been constructed for wheat chromosomes 1D and 7D. These markers will be useful in marker-assisted breeding for RWA-resistant wheat. [ABSTRACT FROM AUTHOR]

Focuses on the registration of KS99WGRC42, a hard red winter wheat with resistance to the Hessian fly. Date of the release as a germplasm; Control of the resistance of KS99WGRC42 to Hessian fly by a single partially dominant gene; Similarity between KS99WGRC42 to the Karl 92 parent in height and days to heading.