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421.
422.
Quantitative trait loci mapping of forage stover quality traits in six mapping populations derived from European elite maize germplasm
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Pengfei Leng Milena Ouzunova Matthias Landbeck Gerhard Wenzel Joachim Eder Birte Darnhofer Thomas Lübberstedt 《Plant Breeding》2018,137(2):139-147
Four forage maize stover quality traits were analysed including in vitro digestibility of organic matter (IVDOM), neutral detergent fibre (NDF), water‐soluble carbohydrates (WSC) and digestibility of NDF (DNDF). We mapped quantitative trait loci (QTL) in three DH (doubled haploid) populations (totally 250–720 DH lines): one RIL population (358 lines) and two testcross (TC) populations, based on field phenotyping at multiple locations and years for each. High phenotypic and genotypic correlations were found for all traits and significant (p < .01) at two locations, and NDF was negatively correlated with the other traits. QTL analyses were conducted by composite interval mapping. A total of 33, 23, 32 and 25 QTL were identified for IVDOM, NDF, WSC and DNDF, respectively, with three, four, five and two major QTL for each. Few consistent QTL for IVDOM, WSC and DNDF were detected in more than two populations. This study contributed to the identification of key QTL associated with forage maize digestibility traits and is beneficial for marker‐assisted breeding and fine mapping of candidate genes associated with forage maize quality. 相似文献
423.
Carbon fractions in soils apparently vary not only in space, but also over time. A lack of knowledge on the seasonal variability of labile carbon fractions under arable land hampers the reliability and comparability of soil organic carbon(SOC) surveys from different studies. Therefore, we studied the seasonal variability of two SOC fractions, particulate organic matter(POM) and dissolved organic carbon(DOC), under maize cropping: POM was determined as the SOC content in particle-size fractions, and DOC was measured as the water-extractable SOC(WESOC) of air-dried soil. Ammonium, nitrate, and water-extractable nitrogen were measured as potential regulating factors of WESOC formation because carbon and nitrogen cycles in soils are strongly connected. There was a significant annual variation of WESOC(coefficient of variation(CV) = 30%). Temporal variations of SOC in particle-size fractions were smaller than those of WESOC. The stocks of SOC in particle-size fractions decreased with decreasing particle sizes, exhibiting a CV of 20%for the coarse sand-size fraction(250–2 000 μm), of 9% for the fine sand-size fraction(50–250 μm), and of 5% for the silt-size fraction(20–50 μm). The WESOC and SOC in particle-size fractions both peaked in March and reached the minimum in May/June and August, respectively. These results indicate the importance of the time of soil sampling during the course of a year, especially when investigating WESOC. 相似文献
424.
Analytic and quality control validation and assessment of field performance of a point‐of‐care chemistry analyzer for use in the White rhinoceros
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425.
Gerhard Langenberger Georg Cadisch Konrad Martin Shi Min Hermann Waibel 《Agroforestry Systems》2017,91(3):577-596
The last decades brought along a tremendous expansion of rubber plantations as well as respective socio-economic transformations. This paper reviews the historical development of rubber cultivation with special reference to intercropping and illustrates the major development steps. The agronomic challenges of intercropping are analyzed and a management classification scheme is suggested. Though the topic of labor always accompanied rubber management, it is nowadays of even higher relevance due to alternative income options, be it due to competing crops such as oil palm, or be it off-farm income opportunities. This development challenges labor intensive permanent intercropping systems. It can thus be concluded that the permanent integration of additional plants needs either to be highly profitable or at least be labor extensive to be adopted on a considerable scale. Given the large area of rubber plantations the latter seems to be more realistic. In this context timber trees might offer promising options if tree selection is properly adapted to site and plantation conditions. Nevertheless, without external interventions, such as land-use planning and implementation, or incentives, the development will be difficult to control. 相似文献
426.
The efficiency of the botanical insecticide (BI) NeemAzal T/S (containing 1% Azadirachtin A), on the basis of azadirachtin
applied in a dose of 20 g a.i. ha−1 against Brassica pod midge (Dasineura brassicae), has been monitored for 4 years. The biological efficiency of BI was compared with the efficiency of some synthetic insecticides.
It was ascertained that BI was very efficient in decreasing the number of damaged oilseed rape pods (ranging from 56.5 to
85.9% compared to untreated plants) and its efficiency was comparable with synthetic insecticides based on Chloronicotinyl
(Thiacloprid) and Neonicotinoid (Acetamiprid). BI’s efficiency was, in some years, even significantly higher compared to pyrethroid
(λ-cyhalothrin). The high biological efficiency of azadirachtin that we ascertained was significantly reflected in increasing
potential crop yields. The yield increase of azadirachtin ranged between 9.3 and 19.4% compared to the control sample. Azadirachtin
showed the highest yield for the whole time of experimentation, and in some years the yield increase was significantly higher
compared to some synthetic agents. 相似文献
427.
Tiemo Kahl Christian Wirth Martina Mund Gerhard Böhnisch Ernst-Detlef Schulze 《European Journal of Forest Research》2009,128(5):467-473
To evaluate the mass of coarse woody debris (CWD), it is necessary to quantify its density. Drill resistance measurements
are introduced as a approach to estimate the density of CWD in different stages of decay. Dead logs of Norway spruce [Picea abies (L.) Karst.] from a Central European mountainous site were used as a test system to compare the new method with conventional
predictors of wood density such as fast quantitative field estimates (e.g., knife probe) and classification of decay classes
based on a set of qualitative traits and quantitative estimates. The model containing only drill resistance as a predictor
explained 65% of the variation in wood density and was markedly better than models containing one or more of several conventional
predictors. However, we show that the relationship between drill resistance and gravimetric wood density relationship is sensitive
to the decay status. Therefore, the best model combines drill resistance and decay class (adj. R2 = 0.732). An additional experiment showed that drill resistance is also sensitive to the moisture state (fresh vs. oven-dry)
of the sample. The major potential of the method lies in its non-destructive nature which allows repeated sampling in long-term
ecosystem studies or in protected areas where destructive sampling is prohibited. The limitations of the method are discussed
and recommendations for applications are given. 相似文献
428.
429.
Development of high-performance strand boards: engineering design and experimental investigations 总被引:1,自引:0,他引:1
Reinhard Stürzenbecher Karin Hofstetter Thomas Bogensperger Gerhard Schickhofer Josef Eberhardsteiner 《Wood Science and Technology》2010,44(1):13-29
Strand-based engineered wood products such as oriented strand boards enjoy great popularity in structural engineering and
are widely used for a variety of applications. To strengthen their competitiveness and to enlarge their range of utilization
particularly in the load-bearing sector, the mechanical properties of these products need to be improved. This motivated the
research efforts to use large-area, slender veneer strands for the production of strand boards with increased stiffness and
strength. Target-oriented development of these products requires comprehending the effects of the relevant (micro-)characteristics,
such as wood quality, strand geometry, and strand orientation and compaction during the production process, as well as layer
assembly and density profile, on the mechanical properties of the finished strand boards. Comprehensive test series, in which
these effects on tension, bending and shear properties of the boards have been studied individually, are presented in this
paper. The obtained results provided insight into the microstructural load-carrying mechanisms and, thus, yielded valuable
knowledge for product optimization and further improvement of custom-designed strand-based engineered wood products. 相似文献
430.
Bäumler S Sierotzki H Gisi U Mohler V Felsenstein FG Schwarz G 《Pest management science》2003,59(3):310-314
A single nucleotide polymorphism (snp) in the cytochrome b gene confers resistance to strobilurin fungicides in Erysiphe graminis DC fsp tritici Marchal. On the basis of this point mutation three different types of molecular markers have been developed. Cleaved amplified polymorphic sequences and allele-specific PCR were used to score resistant and sensitive isolates from specifically selected regional populations across Europe. The results of molecular tests were in total agreement with the resistance phenotypes revealed by in vivo tests. Serial dilutions of mixed samples (resistant/sensitive) delimited the detection for strobilurin-resistant alleles to a range of 10-50% for both marker classes. Due to these detection limits no mixture of mitochondria within individual isolates was found. Denaturing high performance chromatography was used to increase the detection sensitivity for the mutant allele. Although the detection limit was lowered to 5-10%, there was no evidence for the existence of mixed mitochondrial genotypes. 相似文献