Windbreaks are valuable resources in conserving soils and providing crop protection in Great Plains states in the US. Currently, Kansas has no up-to date inventory of windbreaks. The goal of this project was to assist foresters with future windbreak renovation planning and reporting, by outlining a series of semi-automated digital image processing methods that rapidly identify windbreak locations. There were two specific objectives of this research. First, to develop semi-automated methods to identify the location of windbreaks in Kansas, this can be applied to other regions in Kansas and the Great Plains. We used a remote sensing technique known as object-based image analysis (OBIA) to classify windbreaks visible in the color aerial imagery of National Agriculture Imagery Program. We also combined GIS techniques and field survey to complement OBIA in generating windbreak inventory. The techniques successfully located more than 4500, windbreaks covering an approximate area of 2500, hectares in 14 Kansas counties. The second purpose of this research is to determine how well the results of the automated classification schemes match with other available windbreak data and the selected sample collected in the field. The overall accuracy of OBIA method was 58.97 %. OBIA combined with ‘heads up’ digitizing and field survey method yielded better result in identifying and locating windbreaks in the studied counties with overall accuracy of 96 %. 相似文献
The waxy character is achieved in durum wheat (Triticum turgidum L. var. durum) when the granule‐bound starch synthase activity is eliminated. The result is a crop that produces kernels with no amylose in the starch. The presence of two Waxy loci in tetraploid wheat permits the production of two partial waxy wheat genotypes. Advanced full and partial waxy durum wheat genotypes were used to study the effect of waxy null alleles on pasta quality. Semolina from full and partial waxy durum wheats was processed into spaghetti with a semicommercial‐scale extruder, and pasta quality was evaluated. Cooked waxy pasta was softer and exhibited more cooking loss than pasta made from traditional durum cultivars. These features were attributed to lower setback of waxy starch as measured with the Rapid Visco Analyser. High cooking loss may be due to the lack of amylose‐protein interaction, preventing the formation of a strong protein network and permitting exudates to escape. Waxy pasta cooked faster but was less resistant to overcooking than normal pasta. Partial waxy pasta properties were similar to results obtained from wild‐type pasta. This indicates that the presence of a single pair of functional waxy genes in durum wheat was sufficient to generate durum grain with normal properties for pasta production. Waxy durum wheat is not suitable for pasta production because of its softening effect. However, this property may offer an advantage in other applications. 相似文献
Tradable biodiversity credit systems provide flexible means to resolve conflicts between development and conservation land-use
options for habitats occupied by threatened or endangered species. We describe an approach to incorporate the influence of
habitat fragmentation into the conservation value of tradable credits. Habitat fragmentation decreases gene flow, increases
rates of genetic drift and inbreeding, and increases probabilities of patch extinction. Importantly, tradable credit systems
will change the level of fragmentation over time for small and/or declining populations. We apply landscape equivalency analysis
(LEA), a generalizable, landscape-scale accounting system that assigns conservation value to habitat patches based on patch
contributions to abundance and genetic variance at landscape scales. By evaluating habitat trades using two models that vary
the relationship between dispersal behaviors and landscape patterns, we show that LEA provides a novel method for limiting
access to habitat at the landscape-scale, recognizing that the appropriate amount of migration needed to supplement patch
recruitment and to offset drift and inbreeding will vary as landscape pattern changes over time. We also found that decisions
based on probabilities of persistence alone would ignore changes in migration, genetic drift, and patch extinction that result
from habitat trades. The general principle of LEA is that habitat patches traded should make at least equivalent contributions
to rates of recruitment and migration estimated at a landscape scale. Traditional approaches for assessing the “take” and
“jeopardy” standards under the Endangered Species Act based on changes in abundance and probability of persistence may be
inadequate to prevent trades that increase fragmentation. 相似文献
Studies investigating improved protein:lipid ratios based on their effects on growth, nutrient utilization, digestive enzyme activities, blood metabolites and erythogram in tropical carnivorous fish are very scarce. This study evaluated the effect of different protein:lipid ratios on these parameters in the hybrid surubim Pseudoplatystoma corruscans × Leiarius marmoratus. Juvenile fish (8.90 ± 0.94 g initial weight) were fed 3% of total biomass for 60 days using four isoenergetic experimental diets with different protein:lipid ratios (9.00, 4.60, 3.54 and 1.78). Higher growth performance parameters were observed at higher protein:lipid ratios. The activities of intestine total alkaline protease, trypsin and lipase (U/mg protein) were not affected by dietary treatments. Chymotrypsin (U/mg protein) was higher in the 4.60 protein:lipid ratio group. Amylase (U/mg protein) was higher in intermediate groups. Blood glucose, total plasma protein, triglycerides, cholesterol and free amino acids decreased as the protein:lipid ratio decreased. Haematocrit was higher at the 9.00 and 4.60 protein:lipid ratios. Hybrid surubim showed metabolic adaptation to the different protein:lipid ratios tested. These results suggest that the 4.60 protein:lipid ratio showed the best protein‐sparing effect of lipids. 相似文献
ABSTRACT The genome of Tomato leaf curl virus (ToLCV) from Bangalore, India, a whitefly-transmitted geminivirus, was cloned (pIND9) and sequenced. The circular DNA of 2,759 nucleotides (U38239) is organized similarly to that of other begomoviruses with monopartite genomes. Comparison of the nucleotide sequence of pIND9 with other tomato-associated begomoviruses from India (Tomato leaf curl Bangalore virus [ToLCBV, Z48182]) and Tomato leaf curl New Delhi virus-Severe (ToLCNdV-Svr, U15015) showed moderate DNA sequence identities (82 to 87%) between capsid protein (CP) genes but low identities (66 to 67%) for the intergenic regions and the replication-associated protein (Rep) genes (75 to 81% identity). Phylogenetic trees generated with nucleotide sequences of the Rep and CP genes of 26 begomoviruses indicated that this ToLCV is distinct from other begomoviruses and that it may be a recombinant virus derived from at least three different viral lineages. Tomatoes (Lycopersicon esculentum) inoculated with the cloned DNA monomer of ToLCV (pIND9) via particle bombardment developed leaf curling and yellowing symptoms. The virus was transmitted by Bemisia tabaci biotype B from tomatoes infected via particle bombardment to healthy tomatoes and by sap inoculation from infected tomatoes to tomato, Nicotiana benthamiana and N. tabacum. This ToLCV is a distinct member of the genus Begomovirus from India that differs from the previously characterized Tomato leaf curl Sadasivanagar virus isolate Bangalore 1 (L12739), ToLCBV (Z48182), ToLCBV isolate Bangalore 4 (AF165098), and the bipartite ToLCNdV (U15015, U15016). Thus, this ToLCV is named Tomato leaf curl Karnataka virus (ToLCKV). 相似文献
It has long been recognised that steroids can have both organisational and activational effects on the reproductive neuroendocrine axis of many species, including the sheep. Specifically, if the ovine foetus is exposed to testosterone during a relatively short 'window' of in utero development (from approximately day 30-90 of a 147 day pregnancy) the neural mechanisms regulating gonadotrophin releasing hormone (GnRH) secretion become organised in a male-specific manner. In post-natal life the consequences of foetal androgen exposure are sexually differentiated responses of the GnRH neuronal network to activation by factors such as photoperiod and ovarian steroid hormones. Studies in the gonadectomized lamb have demonstrated that elevated concentrations of oestrogen (E) are unable to trigger a preovulatory-like GnRH surge in the male and the androgenized ewe lamb. Further, these animals have markedly reduced sensitivity to the inhibitory actions of progesterone on tonic GnRH release compared with normal ewes. The reasons for these abnormal steroid feedback mechanisms may reside in sexually dimorphic inputs to the GnRH neurone, including those from oestrogen-receptive neurones in the arcuate nucleus that synthetize the neuropeptide, neurokinin B (NKB). The consequences of in utero androgen exposure are reflected in a progressive and dramatic impairment of fertility in the ovary-intact ewe. 相似文献
Human appropriation of net primary productivity (HANPP) is employed as a measure of human pressures on biodiversity, though largely at global and national scales rather than landscape to regional scales where many conservation decisions take place. Though gaining in familiarity, HANPP is not widely utilized by conservation professionals.
Objectives
This study, encompassing the US side of the Great Lakes basin, examines how regional distributions of HANPP relate to landscape-based biodiversity proxy metrics used by conservation professionals. Our objectives were (1) to quantify the HANPP of managed lands at the county scale; and (2) to assess spatial patterns of HANPP in comparison to landscape diversity and local habitat connectedness to determine if the metric can provide useful information to conservation professionals.
Methods
We aggregated forest and cropland NPP data between 2005 and 2015 and coupled it with previously published potential vegetation maps to quantify the HANPP of each county in the study region. We mapped the outputs at 500 m resolution to analyze spatial relationships between HANPP and landscape metrics of biodiversity potential.
Results
Area-weighted HANPP across our study region averaged 45% of NPP, down to 4.9% in forest-dominated counties. Greater HANPP correlated with reduced landscape diversity (p?<?0.001, r2?=?0.28) and reduced local habitat connectedness (p?<?0.001, r2?=?0.36).
Conclusion
HANPP could be used as an additional tool for conservation professionals during regional-scale land use planning or conservation decision-making, particularly in mixed-use landscapes that both support important biodiversity and have high levels of primary production harvest.
Low cost unmanned aerial systems (UAS) have great potential for rapid proximal measurements of plants in agriculture. In the context of plant breeding and genetics, current approaches for phenotyping a large number of breeding lines under field conditions require substantial investments in time, cost, and labor. For field-based high-throughput phenotyping (HTP), UAS platforms can provide high-resolution measurements for small plot research, while enabling the rapid assessment of tens-of-thousands of field plots. The objective of this study was to complete a baseline assessment of the utility of UAS in assessment field trials as commonly implemented in wheat breeding programs. We developed a semi-automated image-processing pipeline to extract plot level data from UAS imagery. The image dataset was processed using a photogrammetric pipeline based on image orientation and radiometric calibration to produce orthomosaic images. We also examined the relationships between vegetation indices (VIs) extracted from high spatial resolution multispectral imagery collected with two different UAS systems (eBee Ag carrying MultiSpec 4C camera, and IRIS+ quadcopter carrying modified NIR Canon S100) and ground truth spectral data from hand-held spectroradiometer.
Results
We found good correlation between the VIs obtained from UAS platforms and ground-truth measurements and observed high broad-sense heritability for VIs. We determined radiometric calibration methods developed for satellite imagery significantly improved the precision of VIs from the UAS. We observed VIs extracted from calibrated images of Canon S100 had a significantly higher correlation to the spectroradiometer (r = 0.76) than VIs from the MultiSpec 4C camera (r = 0.64). Their correlation to spectroradiometer readings was as high as or higher than repeated measurements with the spectroradiometer per se.
Conclusion
The approaches described here for UAS imaging and extraction of proximal sensing data enable collection of HTP measurements on the scale and with the precision needed for powerful selection tools in plant breeding. Low-cost UAS platforms have great potential for use as a selection tool in plant breeding programs. In the scope of tools development, the pipeline developed in this study can be effectively employed for other UAS and also other crops planted in breeding nurseries.