Identifying crop yield gaps with site- and season-specific data-driven models of yield potential     

Filippi  Patrick  Whelan  Brett M.  Vervoort  R. Willem  Bishop  Thomas F. A. 《Precision Agriculture》2022,23(2):578-601

Precision Agriculture - There is considerable interest and value in identifying the gap between crop yields that have actually been achieved, and yields that could have potentially been achieved. A...  相似文献   

Application of the tissue transfer technique in veterinary cytopathology     

Brett M. Stone  David Gan 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2014,43(2):295-302

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IMAGING DIAGNOSIS: MULTIPLE CARTILAGINOUS EXOSTOSES AND CALCINOSIS CIRCUMSCRIPTA OCCURRING SIMULTANEOUSLY IN THE CERVICAL SPINE OF A DOG     

Stephanie Engel  Elissa K. Randall  Paul A. Cuddon  Brett T. Webb  Tawfik A. Aboellail 《Veterinary radiology & ultrasound》2014,55(3):305-309

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Dairy sheep production research at the University of Wisconsin-Madison,USA-a review     

David L Thomas  Yves M Berger  Brett C McKusick  Claire M Mikolayunas 《畜牧与生物技术杂志(英文版)》2014,(2):127-138

Commercial milking of sheep is a new agricultural industry in the United States starting approximately 30 yr ago. The industry is still small, but it is growing. The majority of the sheep milk is used in the production of specialty cheeses. The United States is the major importer of sheep milk cheeses with 50 to 60% of annual world exports coming to the United States during the past 20 yr. Therefore, there is considerable growth potential for the industry in the United States. The only dairy sheep research flock in North America is located at the Spooner Agricultural Research Station of the University of Wisconsin-Madison. The research program started in 1993 and has been multifaceted; dealing with several areas important to commercial dairy sheep farmers. The East Friesian and Lacaune dairy breeds were compared and introduced to the industry through the research program. Both dairy breeds produced significantly more milk than traditional meat-wool breeds found in the U.S., but the two breeds differed in their production traits. East Friesian-cross ewes produced more lambs and slightly more milk than Lacaune-cross ewes whereas Lacaune-cross ewes produced milk with a higher percentage of fat and protein than East Friesian-cross ewes. Lactation physiology studies have shown that ewes with active corpora lutea have increased milk yields, oxytocin release during milking is required to obtain normal fat percentages in the milk, large udder cisterns of dairy ewes can allow for increased milking intervals, and short daylengths during late pregnancy results in increased milk yield. In the nutrition area, legume-grass pastures and forages with a higher percentage of legume will result in increased milk production. Grazing ewes respond to additional supplementation with increased milk yield, but it is important to match the supplement to the quality of the grazing. Ewes on high quality legume-grass pastures that are high in rumen degradable protein respond with increased milk production to supplements high in energy and/or  相似文献   

Effects of Added Shelter and Stocking Density on Growth of Sleepy Cod Oxyeleotris lineolatus in Ponds   总被引：2，自引：0，他引：2  

Brett W.  Herbert Peter A.  Graham Scot D.  Foster 《Journal of the World Aquaculture Society》2003,34(4):433-440

Sleepy cod Oxyeleotris lineolatus is a species of freshwater goby in demand in Australian markets by consumers of Asian origin. It is related to marble goby Oxyeleotris marmoratus , the most expensive freshwater food fish in Asia, which is cultured throughout southeast Asia in ponds and cages. The performance of sleepy cod in culture conditions was investigated to assess the viability of farming them in northern Australia. Sleepy cod fingerlings (62.8 ± 0.8 mm total length and 2.56 ± 0.095 g) were stocked into experimental ponds at 32,857 fish/ha, and grown out for 8 mo. Shelter was provided in each of three replicate ponds and was absent in three control ponds. The provision of shelter in juvenile growout was found to be of no benefit, although fish in ponds provided with shelter weighed slightly more per unit length than fish in ponds without shelter. Cannibalism was not a problem in growout, and survival was close to 100%. After the shelter trial was completed, fish were graded into large and small classes (three replicates of each), and grown out without shelter at the same density for 158 d. Following that, fish were again graded, and the largest 30% retained from growout at a density of 8,857 fish/ha (large, 198 ± 6.44 g) or 10,000 fish/ha (small, 48.9 ± 1.27 g). These were grown out for 188 d. Growth of selected stock at low densities was slower than earlier growth rates, although smaller fish gained weight more rapidly than larger fish. Growth rates were better than the only published data for marble goby. Further investigation into high density culture and different genotypes of sleepy cod needs to be undertaken to determine the viability of pond culture.  相似文献   

Effect of Dietary Phospholipids on Digestion of Neutral Lipid by the Prawn Penaeus monodon     

Brett D.  Glencross David M.  Smith Kevin C.  Williams 《Journal of the World Aquaculture Society》1998,29(3):365-369

Abstract— Different amounts of dietary phospholipid were tested for their effect on the digestibility of total neutral lipids in the diet of the prawn Penaeus monodon . A purified source of the phospholipid, L-α-phosphatidylcholine, was included at 0. 5, 10, 20 or 40 g/kg in a purified diet containing 80 g/kg olive oil as the predominant neutral lipid source. The apparent digestibility of the neutral lipid (ADNL) in these diets was determined by comparing concentrations of the digestibility marker, cholestane in the feed and faeces of the prawns. ADNL (%) increased curvilinearly with increasing dietary phospholipid content (X, %) as described by the equation: ADNL = 80.4 + 9.08X -1.705X² (P < 0.05; R² = 0.71); the asymptote of 92.5% was achieved with a phosphatidylcholine value of 27 g/kg. These results demonstrate that phosphatidylcholine significantly increases the digestibility of neutral lipids by penaeid prawns. However, olive oil was used as the predominant neutral lipid source to examine the effects with a relatively poorly digestible lipid source. The effects of phosphatidylcholine on more readily digested lipid sources such as fish oils, may not be as great, but still be sufficient to improve the utilisation of these nutrients.  相似文献   

Single nucleotide polymorphism markers linked to QTL for wheat yield traits     

Chunlian Li  Guihua Bai  Brett F. Carver  Shiaoman Chao  Zhonghua Wang 《Euphytica》2015,206(1):89-101

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Relationship between relative water content during reproductive development and winter wheat grain yield   总被引：2，自引：0，他引：2  

Makoto Tahara  Brett F. Carver  Richard C. Johnson  Edward L. Smith 《Euphytica》1990,49(3):255-262

Summary Water is often the most limiting factor to winter wheat (Triticum aestivum L.) production in the southern Great Plains of the U.S.A., yet the lack of reliable screening criteria has precluded direct selection for drought resistance in breeding programs. Previous work showed that leaf relative water content (RWC) was highly heritable when measured under field-drought conditions, but its adoption as a screening tool for yield improvement requires further investigation of the genetic relationship between grain yield and RWC. Plants representing high and low yield potential under drought stress, and a random group of plants, were selected from an F₂ population having the pedigree, TAM W-101/Sturdy. Two sets of entries, each comprised of the two parents and 24 F₂-derived lines, were evaluated under a rainshelter in the F₃ (1986) and F₄ (1987) generations to determine differences in leaf RWC during reproductive development. One set of entries did not receive any water after the jointing stage, and the other set was grown under well-watered conditions. A positive relationship was observed between grain yield and RWC measured during anthesis and mid-grain fill, as the high-yield selections maintained a significantly higher RWC than the low-yield selections. Grain yield and RWC were also positively associated among random selections segregating for both traits. Subsequent adjustment of genotype means for differences in reproductive development at time of sampling underscored the need to consider differences in maturity when RWC is the selection criterion.  相似文献   

Enzymatic modification of pectin to increase its calcium sensitivity while preserving its molecular weight     

Hotchkiss AT  Savary BJ  Cameron RG  Chau HK  Brouillette J  Luzio GA  Fishman ML 《Journal of agricultural and food chemistry》2002,50(10):2931-2937

A commercial high-methoxy citrus pectin was treated with a purified salt-independent pectin methylesterase (PME) isozyme isolated from Valencia orange peel to prepare a series of deesterified pectins. A series of alkali-deesterified pectins was also prepared at pH 10 under conditions permitting beta-elimination. Analysis of these pectins using high-performance size exclusion chromatography (HPSEC) with on-line multiangle laser light-scattering, differential viscometer, and refractive index (RI) detectors revealed no reduction in weight-average molecular weight (M(w); 150000) in the PME-treated pectin series, whereas a 16% reduction in intrinsic viscosity (IV) occurred below a degree of esterification (DE) of 47%. In contrast, alkali deesterification rapidly reduced both M(w) and IV to less than half of that observed for untreated pectin. PME treatment of a non-calcium-sensitive citrus pectin introduced calcium sensitivity with only a 6% reduction in the DE. Triad blocks of unesterified galacturonic acid were observed in (1)H nuclear magnetic resonance spectra of this calcium-sensitive pectin (CSP). These results demonstrate that the orange salt-independent PME isozyme utilizes a blockwise mode of action. This is the first report of the preparation of a CSP by PME treatment without significant loss of the pectin's M(w) due to depolymerization.  相似文献   

The effects of belowground resources on aboveground allometric growth in Bornean tree species     

Katherine D. Heineman  Ethan JensenAutumn Shapland  Brett BogenriefSylvester Tan  Richard RebarberSabrina E. Russo 《Forest Ecology and Management》2011,261(11):1820-1832

Tree height and crown allometries reflect adaptations for resource acquisition and structural stability, as well as plastic responses to a heterogeneous environment. While both light and soil resources limit growth and influence competitive responses in tropical forests, the effects of belowground resources on allometries are less understood, especially within the understory. To characterize outcomes of tree competition along an edaphic resource gradient, we quantified variation in height and crown allometries of six Bornean tree species from contrasting regeneration niches (light-demanding vs. shade-tolerant) on two soil habitats (clay-fine loam and sandy loam) within a 52-ha forest dynamics plot. Using empirically-fit allometric parameters and diameter growth rates from plot census data, we modeled tree height and crown area growth over the projected life span of each species. Based on resource competition theory, we hypothesized that tree species specializing on and populations of generalist species growing on the relatively moister, more fertile clay-fine loam soil habitat would have faster height and crown growth rates, compared to those on the sandy loam habitat, regardless of regeneration niche. Among soil specialists and within generalists of both genera, trees growing on clay-fine loam had taller stems and larger crowns at a given age and faster height and crown area growth rates at most sizes than trees on sandy loam. Differences in height and crown growth were driven by the faster diameter growth rates of trees on clay-fine loam, not by differences in height- and crown-diameter allometries, as trees on sandy loam were significantly taller at a given diameter, and differences in crown allometry were not consistent across soil habitats. Characterizing the height and crown growth responses of trees along resource gradients provides insight into the mechanisms that maintain diversity in tropical forests. Our results point to the importance of adaptive and plastic responses to both above and belowground resource availability in determining the allometric growth of trees and suggest that this diversity of responses may contribute tree species coexistence through competition-based trade-off mechanisms and variation in growth among individuals. Additionally, as the importance estimating natural carbon sequestration increases with the escalating effects of anthropogenic climate change, differences in tree growth and architecture across soil habitats also have implications for the approximation of forest carbon storage on heterogeneous tropical soils.  相似文献