Genetic parameters for yield in macadamia     

Craig M. Hardner  Calvin W. Winks  Russ A. Stephenson  Eric G. Gallagher  Cameron A. McConchie 《Euphytica》2002,125(2):255-264

Broad-sense heritability, and genetic and phenotypic correlations were estimated for yield (nut-in-shell; kernel yield; and net present value of crop) per tree in macadamia to 10 years after planting from a trial of 40 cultivars replicated over 4locations. In addition, canopy width at 10years of age was measured and used to calculate yield efficiency as yield per square metre of projected canopy area. Stem girth above the graft union was also measured. There was a low broad-sense heritability (0.06 < H <0.22) and correlation of cultivars across locations (r _gloc = 0.14–0.52) for yield per tree. However, the genetic correlation of cumulative yield was high among 3 of the 4locations (g ≥ 0.75), suggesting the higher genetic variance at Rockhampton was the main cause of the genotype by environmental interaction. Heritability was higher for canopy width (H = 0.28) and yield efficiency (H ≈ 0.47) and cultivar performance was highly correlated across locations (r _gloc ≈ 0.70) for these traits. There was a strong genetic correlation (r _g ≥ 0.90) between cumulative yield per tree of cultivars to 7 years and cumulative yield per tree to 10 years. Genetic correlation among all measures of yield per tree were high (r _g ≥ 0.73), but there was no genetic correlation with canopy width. On the other hand, small cultivars tended to have higher yield efficiency (r _g <–0.62). There was also a slight negative correlation between nut-in-shell yield per tree and kernel recovery (r _g = –0.37). These results suggest the use of family information and index selection may improve the efficiency of selection and breeding programs in macadamia. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Incremental crop tolerance to weeds: A measure for selecting competitive ability in Australian wheats     

Deirdre Lemerle  Alison Smith  Birgitte Verbeek  Eric Koetz  Peter Lockley  Peter Martin 《Euphytica》2006,149(1-2):85-95

Total reliance on herbicides for weed control is unsustainable with the spread of herbicide resistance and the environmental need to reduce pesticide use. Strongly competitive wheat crops that have high tolerance to weed pressure and therefore maintain high yields in the presence of weeds are a low-cost option for reducing dependence on herbicides. We examined the feasibility of selecting for wheat tolerance to weeds by crossing varieties differing for traits associated with competitiveness. Competitive ability and yield potential must be treated as separate traits for selection. Current measures of crop tolerance to weed competition do not separate the two traits so that selection based on these measures is often synonymous with selection for yield potential rather than pure tolerance. We propose a new measure, termed Incremental Crop Tolerance (ICT) that reflects the incremental yield difference between genotypes associated with tolerance, over and above differences in underlying yield potential.  相似文献   

Mark C. Berger (1955‐2003)     

Eric C. Thompson 《Growth and change》2003,34(3):380-383

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Using power priors to improve the binomial test of water quality     

Yuyan Duan  Eric P. Smith  Keying Ye 《Journal of Agricultural, Biological & Environmental Statistics》2006,11(2):151-168

To assess violations of water quality standards, measurements of water quality are collected on a regular basis over a period of time, and are then analyzed to evaluate the percentage of samples exceeding the standard. The challenge to the assessor is that often only a limited amount of data are used to determine if the stream is violating standards. Current assessment uses just the data for a period of two years. To address this issue, we present a Bayesian approach using power priors to incorporate historical information in decision-making. We demonstrate a modified power prior approach and discuss its properties under a binomial model. Exact error probabilities are compared using three approaches: a power prior approach to the binomial test, a Bayesian binomial test with noninformative prior, and a frequentist binomial test. Two examples are presented to illustrate the implementation of the power prior and its differences with alternative binary methods in water quality assessment.  相似文献   

Dry-Weather Metals and Bacteria Loading in an Arid, Urban Watershed: Ballona Creek, California     

Eric D. Stein  Liesl L. Tiefenthaler 《Water, air, and soil pollution》2005,164(1-4):367-382

Dry-season urban runoff from watersheds in arid regions can contribute substantial concentrations and loads of bacteria and metals to downstream receiving waters. However, there are few studies that have evaluated the relative contributions of different sources of these constituents along a specific creek or channel. This study involved analysis of the relative contribution of various storm drain sources to the total dry-season loading of metals and bacteria in the Ballona Creek (California) watershed. Approximately 40 actively flowing storm drains and 12 in-river sites were sampled three times during the spring and summer of 2003 for flow, total and dissolved metals, and bacteria. These data were analyzed in terms of mean concentration and load, temporal variability, and spatial distribution of substantial inputs to the creek. In general, Ballona Creek exhibited a bimodal distribution of elevated metals and bacteria, corresponding to locations where storm drains with consistently high concentrations and loads discharge to the creek. Of the 40 drains sampled, 4 accounted for 85% of the daily storm drain volume. Between 91% and 93% of the total daily load for metals was contributed by eight drains, while nine drains consistently had the highest concentrations of metals and bacteria. Metals concentrations were observed to vary by up to five-fold and bacterial counts by up to five orders of magnitude on an intra- and inter-annual basis. However, despite this variability, a relatively small number of storm drain inputs can be expected to account for the majority of loading.  相似文献   

Time Course Transformations and Fate of Mercury in Aquatic Model Ecosystems     

Emmanuel Tessier  Rosa C. Rodriguez Martin-Doimeadios  David Amouroux  Anne Morin  Christian Lehnhoff  Eric Thybaud  Eric Vindimian  Olivier F. X. Donard 《Water, air, and soil pollution》2007,179(1-4):265-281

In order to achieve remediation of contaminated substrates, phyto-extraction in pot experiments utilizing lettuce seedlings as universal accumulator plants was investigated. As test substrates, mine tailings from Shiheung and Okdong mines in Korea (particularly high in Pb, Zn, Cu, and Cd), as well as samples from historic mining site at Oberzeiring in Austria (particularly high in Pb, Sb and As) were used, and compared with adjacent farmland soils. After 21 days of growth in the test substrate, the lettuce plants were harvested, and the adjacent soils parted in bulk and root soils. Special soil bacteria, adapted to high Cd levels (Exiguobacter sp.) and capable of adsorbing large amounts of cadmium from solution, as well as perlite (Samson Perlite Inc.) were added to the test substrates before plant growth. Speciation changes in the solids were investigated by sequential leaching, utilizing neutral MgCl₂ (exchangeable), 0.16 M acetic acid, hydroxylamine pH 2, oxalate pH 3, H₂O₂ oxidation, and reflux with aqua regia. Plant growth induced differentiation between root and bulk soils, the differences were more pronounced for the non-contaminated controls. The iron-hydroxide phase increased about 30%, and also the amount of iron-hydroxide bound Be, Cd, Co, Cu, Mg, Mo, Sb and V concentrations, coming mainly from less mobile fractions. The Mn hydroxide phase, however (hydroxylamine), remained rather constant. After plant growth, the root soils were significantly lower in available P, and significantly higher in available Ca, Mn, and Na than the corresponding bulk soils. Addition of Cd-adapted soil bacteria led to a severe decrease of plant yield, but metal uptake changed in both directions. Exchangeable P in both root and bulk soil decreased, and Be, Co, Cr, Fe, K, Li, Mg, Mn, Ni, and Sr in the residual organic fraction increased. This can be interpreted as competition for nutrients, dissolution of residuals by bacterial action, and adsorption to a tightly bound biomass. Addition of perlite hardly affected the plant yield, and again metal uptake changed in both directions, but led to a decrease of siderophilic elements in the Fe- and Mn hydroxides of the bulk soil. In the root soil, perlite addition above all decreased available K, P and As, with respect to the untreated samples. Bacteria addition to perlite treated soils shifted some elements from weak acid mobile towards less available fractions.  相似文献   

Front-face fluorescence spectroscopy allows the characterization of mild heat treatments applied to milk. Relations with the denaturation of milk proteins   总被引：2，自引：0，他引：2  

Kulmyrzaev AA  Levieux D  Dufour E 《Journal of agricultural and food chemistry》2005,53(3):502-507

Emission and excitation spectra of intrinsic fluorophores present in milk were used to evaluate changes in milk following thermal treatments in the 57-72 degrees C temperature range from 0.5 min up to 30 min. Alternatively, the concentrations of native alkaline phosphatase, lactoferrin, immunoglobulin G, bovine serum albumin, beta-lactoglobulin, and alpha-lactalbumin were determined in the same samples by enzymatic and immunochemical techniques. As principal component analysis applied to the normalized fluorescence spectra successfully discriminated different milk samples according to the temperature and time of thermal treatment, principal component regression was applied to predict the amounts of the native proteins investigated using fluorescence data. The results showed strong correlations between measured and predicted data for alkaline phosphatase and beta-lactoglobulin. This study has demonstrated that front-face fluorescence spectroscopy has a promising potential to become a rapid and nondestructive analytical technique for the evaluation of physicochemical changes in milk induced by low thermal treatment.  相似文献   

Effects of forest vegetation on spatial variability of surface mineral soil pH,soluble aluminum and carbon     

Susan J. Riha  Gail Senesac  Eric Pallant 《Water, air, and soil pollution》1986,31(3-4):929-940

The purpose of this study was to examine spatial variability in forest soils at several levels including variability due to soil structure, to the presence of individual trees and to populations of different species of trees. Both classic statistical and geostatistical methods were used. Soil chemical properties measured include pH and Al and C in solution which was in equilibrium with the surface mineral soil. Results indicated that soil cores 1.8 cm in diameter were as effective as larger cores in incorporating variability in surface mineral soil pH. There was no spatial correlation in soil pH in samples separated by a distance of 20 to 360 cm. The presence of individual Norway spruce and red pine trees affected soil in their vicinity. Soil pH was depressed and soluble Al elevated. in soil near the base of the tree compared to soil 120 cm from the tree, independent of direction. In addition, in soil sampled at least 100 cm from the base of trees, pH was lower in Norway spruce compared to sugar maple plantations and soluble C was greater in red pine compared to Norway spruce plantations. It is concluded that in less than 50 yr the presence of individual trees and populations of different tree species can affect chemical properties of surface mineral soils. These effects should be considered in the design and interpretation of experiments.  相似文献   

Pro-oxidative characteristics of trout hemoglobin and myoglobin: a role for released heme in oxidation of lipids     

Richards MP  Dettmann MA  Grunwald EW 《Journal of agricultural and food chemistry》2005,53(26):10231-10238

The molecular mass of trout myoglobin was 16017 Da based on electrospray ionization mass spectrometry. A Root effect (low oxygen affinity at pH 6.3) was determined in trout hemoglobin but not myoglobin. At pH 6.3, myoglobin autoxidized more rapidly (3.5-fold) as compared to anodic hemoglobin. Anodic hemoglobin was a better catalyst of lipid oxidation in washed cod muscle as compared to myoglobin at pH 6.3. This suggested that some process other than met heme protein formation was the rate-limiting step in lipid oxidation processes. Heme loss rates were determined using the apomyoglobin mutant H64Y prepared from sperm whale. Anodic hemoglobin released its heme group much more rapidly than myoglobin. In comparisons of anodic and cathodic hemoglobins, heme loss rate better predicted the onset of lipid oxidation than autoxidation rate. These studies collectively suggest that heme dissociation has a primary role in the ability of different heme proteins to promote lipid oxidation processes.  相似文献   

Differentially enhanced insect resistance, at a cost, in Arabidopsis thaliana constitutively expressing a transcription factor of defensive metabolites     

Johnson ET  Dowd PF 《Journal of agricultural and food chemistry》2004,52(16):5135-5138

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