Genetic analysis and genotype × environment (G × E) for grey leaf spot disease resistance in elite African maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) germplasm

Maize grey leaf spot (GLS) disease remains an important foliar disease in sub-Saharan Africa accounting for more than 25% yield losses in maize. Information on inheritance of GLS resistance of germplasm adapted to African environments is required in new sources being identified. Therefore, hybrids generated from a 10 × 10 half-diallel mating of tropical advanced maize inbred lines were evaluated in six environments to determine combining ability, genotype × environment interaction (G × E) and the impact of GLS disease on grain yield. General combining ability effects were highly significant and accounted for 72 and 68% of the variation for GLS resistance and grain yield, respectively. Significant specific combining ability effects associated with reduced disease levels were observed in some hybrids when one parent was resistant, and these may be exploited in developing single cross maize hybrids. Regression analysis showed a 260–320 kg ha^?1 decrease in maize grain yield per each increase in GLS disease severity score, and significant associations (r = ?0.31 to ?0.60) were observed between grain yield and GLS severity scores. This showed the potential of GLS disease to reduce yield in susceptible varieties grown under favourable disease conditions, without control measures. Genotype and genotype × environment biplots and correlation analysis indicated that the significant G × E observed was not due to changes in hybrid ranking, implying absence of a significant crossover interaction. Therefore, predominance of additive gene effects imply that breeding progress for GLS disease resistance would be made through selection and this could be achieved at a few hot-spot sites, such as Baynesfield and Cedara locations in South Africa, and still deploy the resistant germplasm to other environments in which they are adapted.     

Genetic variability of faba bean genotypes for chocolate spot (<Emphasis Type="Italic">Botrytis fabae</Emphasis>) resistance and yield

Faba bean (Vicia faba L.) has high utility as a food and soil fertility improving crop. One of the major fungal pathogens of faba bean is Botrytis fabae, the causative agent of chocolate spot. The disease affects significantly the leaf, stem, pod and seed of faba bean compromise its productivity in the smallholder farming sector. Nonetheless, there are limited resistant/tolerant faba bean varieties available and disease control technology options. Therefore, it was prudent to evaluate faba bean landraces for chocolate spot resistance. Fifty landraces together with ten improved varieties were evaluated both in the field and in the greenhouse under natural and artificial inoculation with previously selected aggressive Botrytis fabae isolate (Iso-016) from West Gojjam, in Ethiopia. There were highly significant differences (p?<?0.001) among the landraces for reaction to the disease and agronomic traits. Significant positive correlation was recorded between reaction of genotypes in the field and greenhouse disease data. The overall mean disease epidemics varied from 92.5 to 697.5 for the area under disease progress curve (AUDPC). The highest level of resistance was found in the ICARDA lines, ILB-4726, ILB-938 and BPL-710. Of all 18 landrace collections displayed significantly lower disease reaction than the susceptible check. However the resistance was moderate. The selected eighteen landraces will be recommended for use in breeding for chocolate resistance. Overall, resistance was highly heritable, suggesting that phenotypic selection can be exploited to improve chocolate spot resistance in faba bean varieties.     

Conventional and future diagnostics for avian influenza

The significant and continued transboundary spread of Asian avian influenza H5N1 since 2003, paired with documented transmission from avian species to humans and other mammals, has focused global attention on avian influenza virus detection and diagnostic strategies. While the historic and conventional laboratory methods used for isolation and identification of the virus and for detection of specific antibodies continued to be widely applied, new and emerging technologies are rapidly being adapted to support avian influenza virus surveillance and diagnosis worldwide. Molecular tools in particular are advancing toward lab-on-chip and fully integrated technologies that are capable of same day detection, pathotyping, and phylogenetic characterization of influenza A viruses obtained from clinical specimens. The future of avian influenza diagnostics, rather than moving toward a single approach, is wisely adopting a strategy that takes advantage of the range of conventional and advancing technologies to be used in "fit-for-purpose" testing.     

Long-term changes in forest floor processes in southern Appalachian forests

Soil nutrient concentrations decreased in an aggrading southern Appalachian forest over a 20-year period. Construction of nutrient budgets showed significant nutrient sequestration aboveground including increased forest floor mass. We hypothesized that the changes in forest floor mass resulted from decreased litter decomposition rates because of decreased litter quality. In 1992 and 1993, we repeated a litter decomposition experiment conducted in 1969 and 1970 to test this hypothesis. In addition, we examined microarthropod populations and functional groups as litter decomposed. For four of the five species tested, first-year decomposition rates were about the same in both experiments. Initial litter nutrient concentrations of P were lower in all tree species in the most recent sampling. N, Ca, and Mg concentrations also declined in some species. These declines often resulted in decreased nutrient release rates during decomposition. Microarthropod populations differed significantly among litter species, as well as between years (probably resulting from differences in growing-season rainfall). For some litter species we found significant relationships between microarthropod populations and nutrient concentration (primarily C and N); however, most r²-values were low. Data suggest that changes in forest floor mass probably resulted from decreased litter quality and that those changes may have an effect on microarthropod populations.     

International Harmonization of Nomenclature and Diagnostic Criteria (INHAND) progress to date and future plans

The INHAND Proposal (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) has been operational since 2005. A Global Editorial Steering Committee (GESC) manages the overall objectives of the project and the development of harmonized terminology for each organ system is the responsibility of the Organ Working Groups (OWG), drawing upon experts from North America, Europe and Japan.Great progress has been made with 9 systems published to date – Respiratory, Hepatobiliary, Urinary, Central/Peripheral Nervous Systems, Male Reproductive and Mammary, Zymbals, Clitoral and Preputial Glands in Toxicologic Pathology and the Integument and Soft Tissue and Female Reproductive System in the Journal of Toxicologic Pathology as supplements and on a web site – www.goreni.org. INHAND nomenclature guides offer diagnostic criteria and guidelines for recording lesions observed in rodent toxicity and carcinogenicity studies. The guides provide representative photo-micrographs of morphologic changes, information regarding pathogenesis, and key references. During 2012, INHAND GESC representatives attended meetings with representatives of the FDA Center for Drug Evaluation and Research (CDER), Clinical Data Interchange Standards Consortium (CDISC), and the National Cancer Institute (NCI) Enterprise Vocabulary Services (EVS) to begin incorporation of INHAND terminology as preferred terminology for SEND (Standard for Exchange of Nonclinical Data) submissions to the FDA. The interest in utilizing the INHAND nomenclature, based on input from industry and government toxicologists as well as information technology specialists, suggests that there will be wide acceptance of this nomenclature. The purpose of this publication is to provide an update on the progress of INHAND.     

Crown allometry and growing space requirements of four rare domestic tree species compared to oak and beech: implications for adaptive forest management

European Journal of Forest Research - Rare domestic tree species are increasingly being viewed as promising alternatives and additions to current main tree species in forests facing climate change....     

Stability of landscape trees in engineered and conventional urban soil mixes

Urban trees are frequently exposed to unsuitable soil conditions that can hamper root system development, potentially affecting both tree health and stability. Engineered soil designs have been developed to increase soil volume for trees planted in confined spaces, and past research has shown that these designs improve growing conditions. However, tree stability in these engineered soils has received limited attention from researchers. In this study, we evaluated the stability of two tree species of contrasting soil quality tolerance (Prunus serrulata and Ulmus parvifolia) after 3 years growth in two skeletal soil mixes, in a suspended pavement design (uncompacted soil), and in a conventionally prepared soil pit. Tree stability was evaluated by measuring trunk resistance to a lateral deflecting force applied with a rope winch system under both ambient and near-saturated soil conditions. Although heavily irrigating the experimental soils had no effect on tree stability, species-specific responses to soil mixes were observed. P. serrulata grown in the gravel-based skeletal soil showed greater trunk deflection resistance than trees grown in the other soil treatments, yet the stability of U. parvifolia was unaffected by soil type. These species-specific responses were consistent with earlier observations of root development in which P. serrulata grew up to 60 times greater root length in gravel-based skeletal soil whereas U. parvifolia root growth was similar in all soil treatments. This research provides evidence that certain tree species planted in conventional tree pits may be more prone to uprooting due to poor root development and that root anchorage might be improved for these species by utilizing a skeletal soil mix.     

Typology of historical sources and the reconstruction of long‐term historical changes of riverine fish: a case study of the Austrian Danube and northern Russian rivers

Historical data are widely used in river ecology to define reference conditions or to investigate the evolution of aquatic systems. Most studies rely on printed documents from the 19th century, thus missing pre‐industrial states and human impacts. This article discusses historical sources that can be used to reconstruct the development of riverine fish communities from the Late Middle Ages until the mid‐20th century. Based on the studies of the Austrian Danube and northern Russian rivers, we propose a classification scheme of printed and archival sources and describe their fish ecological contents. Five types of sources were identified using the origin of sources as the first criterion: (i) early scientific surveys, (ii) fishery sources, (iii) fish trading sources, (iv) fish consumption sources and (v) cultural representations of fish. Except for early scientific surveys, all these sources were produced within economic and administrative contexts. They did not aim to report about historical fish communities, but do contain information about commercial fish and their exploitation. All historical data need further analysis for a fish ecological interpretation. Three case studies from the investigated Austrian and Russian rivers demonstrate the use of different source types and underline the necessity for a combination of different sources and a methodology combining different disciplinary approaches. Using a large variety of historical sources to reconstruct the development of past fish ecological conditions can support future river management by going beyond the usual approach of static historical reference conditions.