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排序方式: 共有2028条查询结果,搜索用时 31 毫秒
31.
Renan C. Lima Pablo H. Teixeira Ari F. F. Souza Trazilbo J. Paula Júnior Hudson Teixeira Miller S. Lehner José E. S. Carneiro Tiago S. Marçal Rogerio F. Vieira 《Plant pathology》2020,69(6):1172-1184
Development of common bean cultivars with partial white mould resistance through breeding techniques has been a challenge in Brazil. As yet, lines/cultivars from breeding programmes have not been investigated for resistance; therefore, this study screened 107 lines/cultivars for their reactions to white mould in 14 preliminary trials conducted under irrigation. Thirteen resistant lines/cultivars (three of Andean origin) and six Mesoamerican cultivars (three intermediately resistant and three susceptible) were selected for further investigation. These lines/cultivars and the resistant control A195 were evaluated in six advanced trials and two straw tests to assess the effectiveness of the screening procedure. In 11 preliminary trials, screenings were performed under moderate/high or higher disease pressure. These pressures occurred in two advanced trials in which, when yields were averaged across moderate/high and high pressures, 10 Mesoamerican lines/cultivars selected for resistance yielded 14%, 23%, and 38% more than intermediately resistant cultivars, A195, and susceptible cultivars, with median disease ratings (1–9 scale) of 4.5, 5.7, 5.7, and 6.7, respectively. In the straw test, three Andean lines/cultivars (A195 included) and two susceptible cultivars in the field were among those with the highest levels of physiological resistance. Thus, field rating under high disease pressure and greenhouse rating did not correlate significantly, suggesting that field trials are critical to evaluating resistance and to identifying high-yielding beans. Therefore, lines/cultivars from breeding programmes assessed in field trials may provide a low cost and fast way to identify high-yielding bean cultivars with partial resistance to white mould in the subtropical southern hemisphere. 相似文献
32.
da Silva Isadora Gonçalves Castoldi Renata de Oliveira Charlo Hamilton César de Souza Miranda Mateus Nunes Thaíssa Dias Cardoso Costa Luciene Lacerda Lemes Ernane Miranda 《Journal of Crop Science and Biotechnology》2020,23(2):191-196
Journal of Crop Science and Biotechnology - The cultivation of sweet corn is expanding in Brazil, but there are serious constraints about the availability of commercial cultivars. The selection of... 相似文献
33.
Yusuf Bozkurt Fatih Öğretmen Uğur Erçin Ümmügülsüm Yιldιz 《Aquaculture Research》2008,39(15):1666-1672
In this research, the mineral and organic composition of the seminal plasma, physical spermatological parameters and their physiological relationships were investigated in grass carp (Ctenopharyngodon idella). The seminal plasma contained 98.14±5.23 mM L?1 (Na+), 380.85±25.95 mM L?1 (K+), 30.25±4.96 mg dL?1 (Ca2+), 19.16±1.70 mEq L?1 (Mg2+), 1.36±0.11 mg dL?1 glucose, 0.37±0.08 g dL?1 total protein, 12.02±1.18 mg dL?1 cholesterol, 14.85±1.50 mg dL?1 triglyceride and 43.5±9.56 mg dL?1 urea. The following spermatological parameters were found: sperm volume 14.44±1.16 mL, sperm motility 80.60±1.55%, movement duration 67.68±4.32 s, density 15.43±0.72 × 109 mL?1, total density 337.43+45.86 × 109 and pH 7.24±0.17. The Na+ and Ca2+ ions correlated negatively with spermatozoa motility (r=?0.453, P>0.05 and r=?0.192, P>0.05) respectively. The K+ ion correlated positively with spermatozoa motility (r=0.545, P>0.05). But a statistically significant correlation was not observed between sperm motility and seminal plasma parameters. The following correlations were observed between mineral and organic components. The Mg2+ was positively correlated with glucose and cholesterol (r=0.692, P<0.05 and r=0.680, P<0.05) respectively. A highly significant positive relationship was also found between Mg2+ and total protein (r=0.837, P<0.01). On the other hand, a significantly negative relationship was found between Ca2+ and triglyceride (r=?0.639, P<0.05). These parameters should be considered when developing procedures for either artificial fertilization or for cryopreservation of grass carp sperm. 相似文献
34.
Dohan Mariam Soma Delwendé Innocent Kiba Nana Ewusi-Mensah Zacharia Gnankambary François Lompo Michel Papoaba Sedogo 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2018,68(5):401-411
Low phosphorus availability in cultivated soils limits sustainable crop production in sub‐Saharan Africa. This study aimed at evaluating the effect of long‐term application of different types of organic amendments on soil P forms, P use efficiency and sorghum yields. A long term experiment established in 1980 at Saria in Burkina Faso, comparing the effects of manure, compost and sorghum straw was used. Manure and compost significantly increased organic P and resin‐P by about 35% and 64%, respectively after 10 and 32 years of sorghum cultivation, and HCl‐P after 32 years of cultivation compared to the control. Manure significantly increased NaHCO3-Pi and NaOH-Pi by 63% and 26%, respectively compared to the control. Sorghum straw had little effect on measured soil P forms. Manure and compost were the best in increasing sorghum grain yield, which effect were strongly correlated to soil pH, carbon and nitrogen. The partial factors productivities of P resulting from the application of studied organic amendments were similar and low, but significantly higher than that of the control treatment. Organic amendments with high P content, maintaining soil carbon and pH could be used to improve soil P availability, sorghum yield and reduce the demand for mineral phosphorus fertilizers. 相似文献
35.
Species composition of arbuscular mycorrhizal fungi in two mountain meadows with differing management types and levels of plant biodiversity 总被引:1,自引:0,他引:1
Boris Börstler Carsten Renker Ansgar Kahmen François Buscot 《Biology and Fertility of Soils》2006,42(4):286-298
Species composition of arbuscular mycorrhizal fungi (AMF) was analysed in two differently managed mountain grasslands in Thuringia
(Germany). Arbuscular mycorrhizal fungi were studied in the roots of 18 dominant plant species from a total of 56 (32%). Additionally,
spores of AMF were isolated from soil samples. Arbuscular mycorrhizal fungi species composition was analysed based on 96 sequences
of the internal transcribed spacer of the nuclear ribosomal DNA, 72 originated from mycorrhizal roots, and 24 originated from
AMF spores. Phylogenetic analyses revealed a total of 19 AMF species representing all genera of the Glomeromycota except Scutellospora and Pacispora. Despite a different farming intensity, resulting in remarkable differences concerning their plant species diversity (27
against 43 plant species), the diversity of AMF was found to be similar with 11 species on the intensively farmed meadow and
ten species on the extensively farmed one. Nevertheless, species composition between both sites was clearly different. It
thus seems likely that the AMF species composition, but not necessarily the species number, is related to above ground plant
biodiversity in the system under study. 相似文献
36.
Faleiro L Miguel G Gomes S Costa L Venâncio F Teixeira A Figueiredo AC Barroso JG Pedro LG 《Journal of agricultural and food chemistry》2005,53(21):8162-8168
Antilisterial activities of Thymbra capitata and Origanum vulgare essential oils were tested against 41 strains of Listeria monocytogenes. The oil of T. capitata was mainly constituted by one component, carvacrol (79%), whereas for O. vulgare three components constituted 70% of the oil, namely, thymol (33%), gamma-terpinene (26%), and p-cymene (11%). T. capitata essential oil had a significantly higher antilisterial activity in comparison to O. vulgare oil and chloramphenicol. No significant differences in L. monocytogenes susceptibilities to the essential oils tested were registered. The minimum inhibitory concentration values of T. capitata essential oil and of carvacrol were quite similar, ranging between 0.05 and 0.2 microL/mL. Antioxidant activity was also tested, the essential oil of T. capitata showing significantly higher antioxidant activity than that of O. vulgare. Use of T. capitata and O. vulgare essential oils can constitute a powerful tool in the control of L. monocytogenes in food and other industries. 相似文献
37.
Oxidation of methane in the rhizosphere of rice plants 总被引:14,自引:0,他引:14
Oxidation of CH4 in the rhizosphere of rice plants was quantified using (1) methyl fluoride, a specific inhibitor of CH4 oxidation, and (2) measuring changes in plant-mediated CH4 emission after incubation under air, N2, or 40% O2. No significant rhizospheric CH4 oxidation was observed from rice plants in the ripening stage. CH4 emission from rice plants 1 week before panicle initiation increased by 40% if CH4 oxidation in the rhizosphere was blocked. The growth stage of the rice plant is an important factor determining the rhizospheric CH4 oxidation. Fluctuation of rhizospheric CH4 oxidation during the growing season may help to explain the observed seasonal CH4 emission patterns in field studies. Measurements from four rice varieties showed that one variety, Pokkali, had higher rhizospheric CH4 oxidation. This was probably because Pokkali was in an earlier growth stage than the other three varieties. Both in the early and in the late growth stages, incubation under N2 caused a much stronger CH4 flux than inhibition of CH4 oxidation alone. Apparently, N2 incubation not only blocked CH4 oxidation but also stimulated methanogenesis in the rhizosphere. Incubation under a higher O2 atmosphere (40% O2) than ambient air decreased the CH4 flux, suggesting that increasing the oxidation of the rice rhizosphere may help in reducing CH4 fluxes from rice agriculture. The O2 pressure in the rhizosphere is an important factor that reduces the plant-mediated CH4 flux. However, inhibition of methanogenesis in the rhizosphere may contribute more to CH4 flux reduction than rhizospheric CH4 oxidation. 相似文献
38.
Fenaille F Visani P Fumeaux R Milo C Guy PA 《Journal of agricultural and food chemistry》2003,51(9):2790-2796
Two headspace techniques based on mass spectrometry detection (MS), electronic nose, and solid phase microextraction coupled to gas chromatography-mass spectrometry (SPME-GC/MS) were evaluated for their ability to differentiate various infant formula powders based on changes of their volatiles upon storage. The electronic nose gave unresolved MS fingerprints of the samples gas phases that were further submitted to principal component analysis (PCA). Such direct MS recording combined to multivariate treatment enabled a rapid differentiation of the infant formulas over a 4 week storage test. Although MS-based electronic nose advantages are its easy-to-use aspect and its meaningful data interpretation obtained with a high throughput (100 samples per 24 h), its greatest disadvantage is that the present compounds could not be identified and quantified. For these reasons, a SPME-GC/MS measurement was also investigated. This technique allowed the identification of saturated aldehydes as the main volatiles present in the headspace of infant milk powders. An isotope dilution assay was further developed to quantitate hexanal as a potential indicator of infant milk powder oxidation. Thus, hexanal content was found to vary from roughly 500 and 3500 microg/kg for relatively non-oxidized and oxidized infant formulas, respectively. 相似文献
39.
40.
V. Maquere J. P. Laclau M. Bernoux L. Saint‐Andre J. L. M. Gonçalves C. C. Cerri M. C. Piccolo J. Ranger 《European Journal of Soil Science》2008,59(5):863-877
In Brazil, most Eucalyptus stands have been planted on Cerrado (shrubby savanna) or on Cerrado converted into pasture. Case studies are needed to assess the effect of such land use changes on soil fertility and C sequestration. In this study, the influence of Cerrado land development (pasture and Eucalyptus plantations) on soil organic carbon (SOC) and nitrogen (SON) stocks were quantified in southern Brazil. Two contrasted silvicultural practices were also compared: 60 years of short‐rotation silviculture (EUCSR) versus 60 years of continuous growth (EUCHF). C and N soil concentrations and bulk densities were measured and modelled for each vegetation type, and SOC and SON stocks were calculated down to a depth of 1 m by a continuous function. Changes in SOC and SON stocks mainly occurred in the forest floor (no litter in pasture and up to 0.87 kg C m?2 and 0.01 kg N m?2 in EUCSR) and upper soil horizons. C and N stocks and their confidence intervals were greatly influenced by the methodology used to compute these layers. C/N ratio and 13C analysis showed that down to a depth of 30 cm, the Cerrado organic matter was replaced by organic matter from newly introduced vegetation by as much as 75–100% for pasture and about 50% for EUCHF, poorer in N for Eucalyptus stands (C/N larger than 18 for Eucalyptus stands). Under pasture, 0–30 cm SON stocks (0.25 kg N m?2) were between 10 and 20% greater than those of the Cerrado (0.21 kg N m?2), partly due to soil compaction (limit bulk density at soil surface from 1.23 for the Cerrado to 1.34 for pasture). Land development on the Cerrado increased SOC stocks in the 0–30 cm layer by between 15 and 25% (from 2.99 (Cerrado) to 3.86 (EUCSR) kg C m?2). When including litter layers, total 0–30 cm carbon stocks increased by 35% for EUCHF (4.50 kg C m?2) and 53% for EUCSR (5.08 kg C m?2), compared with the Cerrado (3.28 kg C m?2), independently of soil compaction. 相似文献