High Frequencies of Fertilization and Haploid Seedling Production in Crosses Between Commercial Hexaploid Wheat Varieties and Maize

Nineteen commercial hexaploid wheat varieties were crossed with the maize F₁ hybrid ‘Seneca 60’. Fertilization frequencies ranged from 32.1 % to 47.5 % of pollinated florets (mean 39.5 %) in the 14 winter wheat varieties and from 40.7 % to 51.4 % (mean 47.8 %) in the five spring wheat varieties. In some cases only an endosperm was formed and the frequencies of embryo formation were therefore slightly lower, being 28.2 % to 45.9 % (mean 36.4 %) for winter wheats and 39.8 % to 48.6 % (mean 45.1 %) for spring wheats. Mean values were significantly higher in the spring wheats but no significant variation was found between varieties within the spring or winter categories. In the five spring wheats the mean yield of embryos, and hence the potential yield of haploid plants, was 3.4-fold higher than with the tetraploid Hordeum bulbosum clone PB179. For the 14 winter wheats the figure was 10.9-fold higher. These differences were highly significant (p < 0.001) in all varieties. A single 2,4-D treatment given to spikes one day after pollination with maize enabled embryos to be recovered from all 19 varieties. A total of 311 embryos were recovered from 950 florets (an average of 7.3 embryos per spike) of which 191 germinated, giving an average yield of one haploid plant for every 5.0 florets pollinated (4.4 haploid plants per spike).     

Cytological Evidence for Fertilization in Hexaploid Wheat × Sorghum Crosses

Crosses were made between the hexaploid wheat ‘Chinese Spring’ (2n = 42) and the diploid grain sorghum ‘S9B’ (2n = 20). Sixty-nine out of 100 florets fixed 48 h after pollination contained an embryo, an endosperm, or both, a remarkably high frequency in view of the taxonomic distance spanned by the cross. Percentages of single or double fertilization ranged from 50 % to 91 % for individual spikes. The hybrid origin of the embryos was confirmed by examining zygotes from spikes fixed 25 to 27 h after pollination. Seven of the 8 zygotes in which chromosomes were sufficiently contracted to be counted contained 21 large wheat chromosomes and 10 much smaller sorghum chromosomes. The eighth contained 21 chromosomes from wheat and 20 from sorghum. Sorghum chromosomes did not appear to be attached to the spindle in zygote nietaphases and showed no evidence of movement towards the spindle poles in the single zygote anaphase found. Embryos with two or more cells invariably contained one or more micronuclei and metaphases in embryos with three or more cells contained only 21 wheat chromosomes showing that sorghum chromosomes were rapidly eliminated. Endosperm, when present, was always highly abnormal.     

Mapping of QTL controlling NIR predicted hot water extract and grain nitrogen content in a spring barley cross using marker-regression

A restriction fragment length polymorphism (RFLP) map constructed from 99 doubled haploid lines of a cross between two spring barley varieties (‘;Blenheim’בKym’) was used to map QTL controlling hot water extract and grain nitrogen content (predicted by analysis with near-infrared reflectance spectroscopy). Eight QTL affecting predicted hot water extract were identified by a marker-regression approach. The largest effects were found on chromosomes 3HL, associated with the denso dwarfing gene which is present in‘Blenheim’and conferred poorer predicted hot water extract quality, and 4HL. Other QTL were detected on chromosomes IHS. IHL. 2HS, 2HL. 5HL and 6HS. Analysis of single markers by analysis of variance detected an additional effect on chromosome 1H. Eight QTL affecting predicted grain nitrogen content were identified by marker-regression, on chromosomes 1HS, 1HL. 2HL. 5HS, 6H, 7HS and 7HL. There was also evidence for an additional QTL on chromosome 5HL. The positions of the grain nitrogen content QTL on 5HS and 5HL are comparable to QTL on wheat chromosomes 5A and 5D that affect grain protein content. The denso gene had no detectable effect on grain nitrogen content.     

Light wavelength effects on a lutein-fortified model colloidal beverage

The effect of light on a model colloidal beverage system containing whey protein, lutein, and limonene was investigated. Changes in volatile chemistry were evaluated under accelerated conditions (12 h, 25 °C) at selected wavelengths regions (395, 463, 516, 567, and 610 nm absorbance maxima) using a photochemical reactor. The most damaging wavelengths to lutein stability were UV (200-400 nm) and 463 nm wavelengths. Hexanal formation was highest in the control beverage when exposed to full spectrum light and UV (200-400 nm) wavelengths. Hexanal also was formed in the lutein-fortified beverage under full spectrum light and UV (200-400 nm) wavelengths but to a significantly lesser degree. Limonene degraded significantly under all treatment conditions, with most degradation occurring during full spectrum light exposure. Lutein fortification did not completely protect limonene from degradation.     

Temporal and spatial patterns of wetland extent influence variability of surface water connectivity in the Prairie Pothole Region,United States

Context

Quantifying variability in landscape-scale surface water connectivity can help improve our understanding of the multiple effects of wetlands on downstream waterways.

Objectives

We examined how wetland merging and the coalescence of wetlands with streams varied both spatially (among ecoregions) and interannually (from drought to deluge) across parts of the Prairie Pothole Region.

Methods

Wetland extent was derived over a time series (1990–2011) using Landsat imagery. Changes in landscape-scale connectivity, generated by the physical coalescence of wetlands with other surface water features, were quantified by fusing static wetland and stream datasets with Landsat-derived wetland extent maps, and related to multiple wetness indices. The usage of Landsat allows for decadal-scale analysis, but limits the types of surface water connections that can be detected.

Results

Wetland extent correlated positively with the merging of wetlands and wetlands with streams. Wetness conditions, as defined by drought indices and runoff, were positively correlated with wetland extent, but less consistently correlated with measures of surface water connectivity. The degree of wetland–wetland merging was found to depend less on total wetland area or density, and more on climate conditions, as well as the threshold for how wetland/upland was defined. In contrast, the merging of wetlands with streams was positively correlated with stream density, and inversely related to wetland density.

Conclusions

Characterizing the degree of surface water connectivity within the Prairie Pothole Region in North America requires consideration of (1) climate-driven variation in wetness conditions and (2) within-region variation in wetland and stream spatial arrangements.

     

Do fences protect birds from human disturbance?

Outdoor recreation and ecotourism are becoming increasingly popular, but such human activities are not entirely benign to birds. One way to manage wildlife habitats is to restrict public access with a fence or some similar barrier, under the assumption that this provides wildlife with a refuge from human activities. We tested this assumption by measuring the responses of 10 species of birds at a site containing a fence with a relatively large number of visitors on only one side. We compared these responses to those at a less-visited, control site. Responses were measured by quantifying flight initiation distance (FID), the distance birds would allow a human to approach before fleeing. Overall, we found birds on the protected side of the fence responded similarly to birds at the low visitation control site, and significantly differently from birds at the high visitation site. Our results suggest that by reducing the number of humans and providing areas of refuge within highly visited habitats, protective barriers allow birds to behave as they would in an undisturbed environment.     

Hemorrhagic Gastritis Associated with Renal Failure, Hemoglobinuria, and Isolation of Clostridium perfringens in a Horse

A 3-year-old Quarter Horse mare was presented for acute colic with bright red-black foul-smelling gastric reflux containing long rod-shaped bacteria consistent with Clostridium sp. and red-black urine. The serum creatinine concentration was 5.5 mg/dL (N = 0.9–1.7), and blood urea nitrogen was 41 mg/dL (N = 9–20). At necropsy, the stomach wall was diffusely thickened, hemorrhagic, and edematous. Histopathologically, hemorrhagic necrosis was evident, with numerous colonies of spore-forming rods within the submucosa. Clostridium perfringens was cultured from the stomach contents. Polymerase chain reaction (PCR) genotyping was consistent with type A C. perfringens. Bilaterally, the kidneys were grossly enlarged, diffusely dark red-brown, and congested. The renal tubular epithelium was diffusely, acutely necrotic, with interstitial hemorrhage and massive accumulation of intratubular granular and proteinaceous casts. A diagnosis of massive hemolysis with hemoglobinuria and renal failure due to C. perfringens, type A infection was made. Alpha-toxin–induced intravascular hemolysis occurs rarely in humans and sheep. To our knowledge, this has not been described in horses with clostridial enterocolitis nor in equine clostridial gastritis.     

Canine elliptocytosis due to a mutant β‐spectrin

Abstract: A 5‐year‐old, spayed female, mixed‐breed dog with persistent elliptocytosis was evaluated at the Veterinary Medical Teaching Hospital at Kansas State University. The elliptocytosis was asymptomatic and was detected during the evaluation of lameness. When subjected to shear stress in an ektacytometer, the dog's erythrocytes had reduced cellular deformability and erythrocyte membranes had decreased mechanical stability. Analysis of erythrocyte membrane spectrin by nondenaturing gel electrophoresis revealed an increased amount of spectrin dimers, indicating a defect in spectrin self‐association. DNA analysis detected a β‐spectrin mutation in codon 2110 in which threonine was replaced by methionine. This mutation likely altered the molecular structure of the erythrocyte membrane, leading to impaired spectrin self‐association and elliptocyte formation.