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51.
Genetic association mapping has been widely applied to determine genetic markers favorably associated with a trait of interest and provide information for marker-assisted selection. Many association mapping studies commonly focus on main effects due to intolerable computing intensity. This study aims to select several sets of DNA markers with potential epistasis to maximize genetic variations of some key agronomic traits in barley. By doing so, we integrated a MDR (multifactor dimensionality reduction) method with a forward variable selection approach. This integrated approach was used to determine single nucleotide polymorphism pairs with epistasis effects associated with three agronomic traits: heading date, plant height, and grain yield in barley from the barley Coordinated Agricultural Project. Our results showed that four, seven, and five SNP pairs accounted for 51.06, 45.66 and 40.42% for heading date, plant height, and grain yield, respectively with epistasis being considered, while corresponding contributions to these three traits were 45.32, 31.39, 31.31%, respectively without epistasis being included. The results suggested that epistasis model was more effective than non-epistasis model in this study and can be more preferred for other applications. 相似文献
52.
A. Rigotto S.R. Cotta A.C.F. Dias J.L.N. Carvalho F.D. Andreote 《Letters in applied microbiology》2020,71(5):444-450
Sugarcane cultivation supports Brazil as one of the largest world sugar and ethanol producer. In order to understand the impact of changing sugarcane harvest from manual to mechanized harvest, we studied the effect of machinery traffic on soil and consequently soil compaction upon soil microbial communities involved in nitrogen cycling. The impact of sugarcane harvest was dependent on soil depth and texture. At deeper soil layers, mechanized harvesting increases the abundance of nitrogen fixers and denitrifying communities (specifically nosZ clade I and II) while manual harvesting increases the abundance of ammonia oxidizers (specifically AOA) and increases denitrifying communities (nosZ clade I and II) on top and at intermediate depth. The effect of change on the harvest system is more evident on sandy soil than on clay soil, where soil indicators of compaction (bulk density and penetration resistance) were negatively correlated with soil microorganisms associated with the nitrogen cycle. Our results point to connections between soil compaction and N transformations in sugarcane fields, besides naming biological variables to be used as proxies for alterations in soil structure. 相似文献
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Paul M. Severns 《Journal of Insect Conservation》2008,12(6):651-661
Fender’s blue butterfly is an endangered species restricted to fragmented, grassland remnants that are becoming increasingly
dominated by tall, invasive grasses in western Oregon, USA. I performed a removal experiment to assess the impacts of structural
degradation accompanying the invasion of Arrhenatherum elatius, tall oat grass, on butterfly fitness and fitness related behaviors. Clipping of A. elatius to native grass sward height resulted in 2.5–5 times as many eggs laid per leaf of host plant. Both male and female butterflies
basked more frequently in areas removed of A. elatius inflorescences and upon encountering the treatment edge butterflies had a high rate of return into a large area removed of
the grass inflorescences. Although butterfly behavior appeared to be affected by the change in sward height on the treatment
edge, there was no evidence for the edge causing a disproportionate egg load. Invasion and dominance by A. elatius appeared to diminish host plant apparency which may result in overloading of eggs on conspicuous host plants, increased incidence
of emigration, and a decrease in the likelihood of colonization because female butterflies appeared indifferent to larval
resources beneath A. elatius inflorescences. Dominance of natural shortgrass prairies by tall stature grasses like A. elatius may be an insidious form of habitat degradation for grassland Lepidoptera worldwide, but it may go largely unnoticed because
larval and adult resources can persist under the unnaturally tall grass canopy. 相似文献
57.
Patterns generated from ecological surveys are rarely tested in similar habitats to assess the accuracy of predictions. Testing empirically derived predictions provides a strong tool for establishing the consistency of general patterns in ecology. We test the consistency of beetle community associations with habitat complexity in open canopy forests and make both community and morphospecies-level comparisons with results from a previous study. We use Normalized Difference Vegetation Indices (NDVIs) from remote sensing as a surrogate for habitat complexity. The positive relationships between NDVIs and site-based beetle species richness and abundance were consistent in open canopy forests both south and north of Sydney, Australia. NDVIs were also useful for predicting differences in beetle composition in open canopy forests. Taxon-specific responses to NDVI differences in 'southern forests' were very similar to responses in 'northern forests', most likely reflecting beetle trophic roles. This study shows that NDVIs can be used as rapid biodiversity indicators, when integrated with identified faunal responses to vegetation structure, provided that the lower vegetation strata may be measured by remote sensing. 相似文献
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A recursive least squares based on Multi-model is proposed for non-uniformly sampled-data nonlinear (NUSDN) systems. The corresponding state space model of an NUSDN system is derived using lifting technique. Taking advantage of the Fuzzy c-Mean Clustering algorithm, NUSDN is divided into several local models. The basic idea is that the NUSDN system is viewed as a model switching system under a given rule. Once the local models are identified, the global model is determined. A pH neutralization process validate the performance of the proposed algorithm. 相似文献
60.
Andreas König 《European Journal of Wildlife Research》2008,54(1):101-109
Throughout Central Europe, foxes have taken over urban areas as their habitat. In Southern Germany, these foxes are also carriers
of the small fox tapeworm, which causes a serious zoonotic infection in humans. Therefore, a survey was carried out in a suburb
of the city of Munich. A postal questionnaire was used to analyse the attitudes, opinions and fears of these participants
towards their urban foxes and the background to these attitudes. Questionnaires were sent to all households with gardens and
collected in again via the community council. Seven hundred and seventy-nine or 31% of questionnaires were returned. Only
a few people are afraid of the fox itself; however, 55% are afraid of the fox tapeworm. Worming the animals is the preferred
counter-measure, with 81% in favour. The majority of inhabitants are pleased to see a fox in the community and feel the animals
have a right to live. People are afraid of the tapeworm either because they have children in the household or because of increased
knowledge of the subject or because it has increasingly become an issue. On the basis of the results of this study, it is
to be expected that radical solutions such as killing the foxes are unlikely to be accepted among the population. Worming
of the foxes does, however, meet with general approval. 相似文献