Reproduction of Mm.106 Rootstocks Propagated by Stooling as Affected by Organic Sources

Six organic sources of nutrients including commercial organic fertilizer (CF), poultry litter (PL), green compost (GC), wood chips (WC), shredded paper (SP), grass clippings (GR), and extracts from water (NF, as a control) were investigated under controlled conditions. One-year-old MM.106 apple (Malus × domestica Borkh.) trees grown under greenhouse conditions in 10 L pots were treated with nutrient solutions. All treatments were applied proportionally based on the volume ratio of material recommended for organic apple orchard field production. A nutrient solution from GC provided the greatest total nitrogen (N) input over the 12-week experimental period, followed in order by the GR, PL, WC, CF, SP, and NF treatments. The PL- and GR-treated plants had the largest stem diameter, largest leaf area, longest stem extension, and fastest dry matter production rate, as well as greater carbon dioxide (CO₂) assimilation, SPAD readings, N accumulation, and N use efficiency.     

Defining the ecological values of rivers: the views of Australian river scientists and managers

• 1. The first step in making a case for river conservation is to define the particular values and attributes that describe conservation significance.
• 2. Australia's rivers vary widely in their characteristics and ecological communities. The conservation values of Australian rivers have not been well articulated.
• 3. A survey of Australian river scientists and managers was undertaken to identify the criteria and attributes of rivers of high ecological value. This was the first attempt to establish a baseline for defining natural conservation values for Australian rivers.
• 4. The final list comprised five broad criteria with a total of 47 attributes considered to be indicators of high ecological value. These included not only biotic values, but also values attributed to river hydrology, geomorphology, instream processes, and landscape functions.
• 5. The list of criteria and attributes provides a context from which specific values may be drawn to assess conservation values of rivers for particular purposes.

Copyright © 2004 John Wiley & Sons, Ltd.     

Response to root-knot nematodes of a germplasm collection of red clover and related species

A germplasm collection of red clover (Trifolium pratense L.) and seven related species was evaluated in greenhouse tests for resistance to Meloidogyne arenaria (Neal) Chitwood, M. hapla Chitwood, M. incognita (Kofoid & White) Chitwood, and M. Javanica (Treub) Chitwood. Plants were rated for root galling severity and nematode egg production at eight weeks after inoculation with 1500 nematode eggs. A resistance index, RI = (gall₂; + egg₂;), was generated to assess the plants' reaction to nematode infection as immune, highly resistant, resistant, moderately resistant, intermediate, moderately susceptible, susceptible, or highly susceptible. More than 98% of red clover accessions were intermediately to highly susceptible to all four root-knot nematode species. Only one accession, PI 271627 introduced from India, had a moderate resistance level to the four nematodes tested. About one third of the T. medium accessions were resistant or highly resistant to M. arenaria, M. incognita, and M. javanica whereas more than 50% of the T. alpestre accessions were highly resistant or immune to all four nematodes species. Genetic factors for resistance to root-knot nematode could be introduced into T. pratense through interspecific hybridization with T. medium and/or T. alpestre     

Rice growth, yield and water productivity responses to irrigation scheduling prior to the delayed application of continuous flooding in south-east Australia

The majority of rice grown in south-east Australia is continuously flooded for much of its growing season, but reduced irrigation water availability brought about by a combination of drought and environmental flow legislation has presented a need to maintain (or even increase) rice production with less irrigation water. Delaying the application of continuous flooding until prior to panicle initiation can increase input water productivity by reducing non-beneficial evaporation losses from free water and the soil. A field experiment was conducted over two growing seasons, 2008/9 and 2009/10, comparing a conventional dry seeded treatment (the control - continuous flooding from the 3 leaf stage) with delayed continuous flooding (10-20 days prior to panicle initiation) with several irrigation scheduling treatments prior to flooding commencement. In the first year, the delayed water treatments were irrigated at intervals of 40, 80 and 160 mm of cumulative reference evapotranspiration (ETo) prior to delayed continuous flooding, thereby imposing differing degrees of crop water stress. In year 2, the 80 and 160 mm treatments were modified by use of a crop factor (Kc) when the plants were small and the 40 mm treatment was replaced with a continuously flooded treatment throughout the crop duration.Decreases in net water input (irrigation + rain − surface drainage) and increases in input water productivity were achieved by reducing the flush irrigation frequency during the pre-flood period. Savings of 150 and 230 mm (10 and 15%) were achieved in Year 1 from the 80 and 160 mm cumulative ETo irrigation frequency treatments, respectively, in comparison to the control. In the second year, net water input savings of 230 and 330 mm (15 and 22%) were achieved with the 80/Kc and 160/Kc mm treatments, respectively. Input water productivity of the 160 mm treatment was 0.06 kg/m³ (8%) higher than the control in Year 1, while in Year 2 a 0.15 kg/m³ (17%) increase in input water productivity above the control was achieved by the 160/Kc mm treatment. Delaying the application of continuous flooding in the second year greatly extended the period of crop growth suggesting the need for earlier sowing (by 7-10 days) to ensure pollen microspore still occurs at the best time to minimise yield loss due to cold damage. Nitrogen fertiliser management is an important issue when delaying continuous flooding, and nitrogen losses appeared to increase with the frequency of irrigation prior to continuous flooding. This was likely due to increased denitrification from alternate wetting and drying of the soil. Further research is required to determine the most appropriate nitrogen management strategies, and to also better define the optimal pre-flood irrigation frequency.     

Brucella melitensis infection following military duty in Iraq

Brucellosis is a common zoonotic disease worldwide; however, few cases are reported in the US. Brucella melitensis infections are primarily acquired via consumption of high-risk foods or travel to endemic areas. We describe a case of B. melitensis infection in a Tennessee soldier following deployment in Iraq. Initial symptoms included knee and back pain. Culture of an aspirate of the left sacroiliac joint yielded B. melitensis. Genetic analysis indicated that this isolate came from the Middle East. Investigation of laboratory workers identified risky exposures and positive serology prompting post-exposure prophylaxis. Military personnel and other travellers should be advised to reduce risk regarding food consumption and animal contact in endemic areas. Additionally, medical providers should remain vigilant for non-endemic zoonoses among recent travellers.     

Scaling relations between riparian vegetation and stream order in the Whitewater River network,Kansas, USA

Riparian communities have been well-studied along individual streams, but not within the context of networks of which streams are a part. To study networks, hydrologists use Horton–Strahler ordering to assign streams to discrete categories in which increasing numerical value (ω) reflects increasing size of the stream and complexity of the network. A key use of this classification method has been to demonstrate scaling relations between hydrogeomorphic variables and order. These relations now provide a foundation to determine how ecological processes are associated with the geometry and topology of river networks. We used geographic information systems (GIS) to map and measure the stream network and riparian vegetation of the Whitewater River basin of eastern Kansas, USA. With the resulting data, we tested if (1) riparian vegetation scaled with order, and (2) riparian vegetation at confluences of two streams differed from that found along constituent streams. Most characteristics of riparian vegetation scaled with order. In confluence zones, density and diversity of riparian vegetation generally were equivalent to that of the largest constituent stream. Scaling relations between riparian vegetation and order provide a framework to quantify the role of riparian vegetation in the water balance of stream networks and a tool to predict area and distribution of riparian vegetation from network topology.     

Multiple bluetongue virus-cloned genetic probes: application to diagnostics and bluetongue virus genetic relationships

A shotgun-cloning method incorporating all 10 bluetongue virus genome segments can simultaneously produce complete and partial copies of any of the genome segments. We report here 4 different cloned probes derived from 3 genome segments and individually defined by different hybridization recognition capabilities. One probe hybridized strongly with all 5 United States prototype strains of the 5 different bluetongue virus (BTV) serotypes existing in the United States and, as such, is a strong candidate for a broad BTV diagnostic probe in the United States. Another probe derived from genome segment 2 of BTV-17 hybridized only with the BTV-17 prototypic serotype, thereby demonstrating serospecific hybridization diagnostic potential. The implications for diagnostic and genetic relationship studies on BTV, using various genetic probes, are discussed.     

Evidence of Brucella sp. infection in marine mammals stranded along the coast of southern New England.

After recent isolations of Brucella sp. from pinnipeds and cetaceans, a survey was initiated to investigate the prevalence of Brucella sp. infections and serologic evidence of exposure in marine mammals stranded along the coasts of Connecticut and Rhode Island. One hundred and nineteen serum samples from four species of cetaceans and four species of pinnipeds were collected from 1985 to 2000 and tested for antibodies to Brucella sp. using the brucellosis card test, buffered acidified plate antigen test, and rivanol test. In addition, 20 of these were necropsied between 1998 and 2000, with lymphoid and visceral tissues cultured for Brucella sp. Three of 21 (14%) harbor seals (Phoca vitulina) and four of 53 (8%) harp seals (Phoca groenlandica) were seropositive. Brucella sp. was isolated from two of four (50%) harbor seals and three of nine (33%) harp seals. Of the five animals with positive cultures, two were seropositive and three seronegative. Brucella sp. was most frequently cultured from the lung and axillary, inguinal, and prescapular lymph nodes. Tissues from which Brucella sp. was isolated showed no gross or histopathologic changes. These results indicate that marine mammals stranded along the coast of southern New England can be exposed to and infected with Brucella sp.