Heritability of, and genetic correlations among, forage and seed yield traits in Ladino white clover   总被引：1，自引：0，他引：1  

P. Annicchiarico    E. Piano  I. Rhodes 《Plant Breeding》1999,118(4):341-346

Sixteen white clover genotypes and their half-sib progenies were grown in pure stand. Each clover progeny was also grown in a mixed stand that also included three grass varieties of different species. Dry matter (DM) yield was measured over 2 years and seed yield at the second year. Competitive ability of clover families was defined as the ratio between mixed stand and pure stand for clover DM yield. Narrow-sense heritability from parent-offspring regression of pure stand data was high to moderate (h²0.50) for DM yield, seed yield and most of their components. Persistence as predicted by stolon density showed negative genetic correlations with seed yield (r_g= -0.70) and DM yield (r₂= -0.60), whereas seed yield and DM yield tended towards a negative correlation (r₂=0.45). Sizes of different vegetative or reproductive organs were generally correlated positively. Evidence was provided that the set of parent genotypes represents well the genetic variation available within the Ladino gene pool. The results highlighted the difficulty of combining relatively short-term DM yield, persistence and seed yield into a unique plant type. Differences in competitive ability emerged only in the second year, better ability being related mainly to petiole length among the traits assessed in pure stand.  相似文献   

Measurements of the equation of state of deuterium at the fluid insulator-metal transition   总被引：1，自引：0，他引：1  

GW Collins  Da Silva LB  P Celliers  DM Gold  ME Foord  RJ Wallace  A Ng  SV Weber  KS Budil  R Cauble 《Science (New York, N.Y.)》1998,281(5380):1178-1181

A high-intensity laser was used to shock-compress liquid deuterium to pressures from 22 to 340 gigapascals. In this regime deuterium is predicted to transform from an insulating molecular fluid to an atomic metallic fluid. Shock densities and pressures, determined by radiography, revealed an increase in compressibility near 100 gigapascals indicative of such a transition. Velocity interferometry measurements, obtained by reflecting a laser probe directly off the shock front in flight, demonstrated that deuterium shocked above 55 gigapascals has an electrical conductivity characteristic of a liquid metal and independently confirmed the radiography.  相似文献   

Evaluation of seed production potential in white clover (Trifolium repens L. varietal improvement programmes     

T. A. Williams  M. T. Abberton  W. J. Thornley  D. R. Evans  I. Rhodes 《Grass and Forage Science》1998,53(2):197-207

The components of actual and potential seed yield were examined in field experiments on a wide range of varieties of white clover (Trifolium repens L.). The factors affecting seed yield under conditions typical of management regimes used in the production of commercial seed crops were assessed in two experiments. In the first, carried out on spaced plants, considerable diferences are shown between six varieties across the range of leaf sizes in the distribution and profuseness of inflorescence production through the flowering season. In the second, carried out in plots, typical on-farm criteria were used to choose a single harvest date. Significant variation was found between varieties, including representatives of different leaf size categories, for seed yield components that include number of inflorescences m^?2, number of florets per inflorescence and harvestable seed weight. Large-leaved varieties tended to produce more seeds per floret and higher seed weights per inflorescence, whereas small-leaved varieties gave the highest number of inflorescences ^?2. However, the small-leaved variety AderDale, selected for strong peduncles, was exceptional, giving high values for all seed yield components. The impact of weather conditions on many seed yield components (e.g. total number of inflorescences) was demonstrated by the differences between the 2 years of the experiment. However, other characterstics, e.g. number of florets per inflorescence and number of seeds per floret, did not vary between years. Deviations from potential seed yield were assessed fromthe perspective of commerical seed production. The implications of these results for the production of white clover varieties with increased seed yields under UK conditions are discussed.  相似文献   

An approximately 15,000-year record of El Nino-driven alluviation in southwestern ecuador     

DT Rodbell  GO Seltzer  DM Anderson  MB Abbott  DB Enfield  JH Newman 《Science (New York, N.Y.)》1999,283(5401):516-520

Debris flows have deposited inorganic laminae in an alpine lake that is 75 kilometers east of the Pacific Ocean, in Ecuador. These storm-induced events were dated by radiocarbon, and the age of laminae that are less than 200 years old matches the historic record of El Nino events. From about 15,000 to about 7000 calendar years before the present, the periodicity of clastic deposition is greater than or equal to 15 years; thereafter, there is a progressive increase in frequency to periodicities of 2 to 8.5 years. This is the modern El Nino periodicity, which was established about 5000 calendar years before the present. This may reflect the onset of a steeper zonal sea surface temperature gradient, which was driven by enhanced trade winds.  相似文献   

NECROTIZING ENCEPHALITIS IN A YORKSHIRE TERRIER: CLINICAL, IMAGING, AND PATHOLOGIC FINDINGS     

Donatella  Lotti  DVM  PhD  Maria Tresa  Capucchio  DVM  Elena  Gaidolfi  DM  Monica  Merlo  DVM 《Veterinary radiology & ultrasound》1999,40(6):622-626

A 5-year-old, male Yorkshire Terrier had chronic and progressive neurologic signs compatible with lesions in the right brain stem and right forebrain. In magnetic resonance images of the brain there were multifocal lesions at different stages of evolution, consistent with an inflammatory disease. The lesions were located in the white matter of the cerebrum, in the diencephalon and mesencephalon. These lesions were hypointense in T1-weighted images and hyperintense in T2-weighted images with no mass effect and minimal enhancement with gadolinium. Necrotizing encephalitis was confirmed post mortem.  相似文献   

Development of plant‐based diets and the evaluation of dietary attractants for juvenile Florida pompano,Trachinotus carolinus L.          下载免费PDF全文

M.A. Rhodes  Y. Zhou  G.P. Salze  T.R. Hanson  D.A. Davis 《Aquaculture Nutrition》2017,23(5):1065-1075

Sustainable and profitable commercial aquaculture production of marine fish species is dependent on the development of sustainable protein sources as substitutes for expensive animal meals such as fishmeal (FM). Previous Florida pompano Trachinotus carolinus studies have indicated that poultry by‐product meal (PBM) and meat and bone meal can be used to produce a FM‐free diet if suitable levels of nutrients (such as taurine) are included in the diets. In this study, we attempted to develop an all‐plant protein diet by removing the animal proteins in practical diets for pompano by substituting back select ingredients. A series of eight FM‐free diets were formulated, four systematically replaced soybean meal (SBM) with soy protein concentrate (SPC) and four replaced PBM with SPC. Based on the results, there is no clear disadvantage to the use of SPC as a replacement for SBM. However, the complete removal of PBM resulted in reduced performance. Two additional growth trials were conducted to supplement additional amino acids including glycine, valine and histidine, a proprietary chemical attractant mix, fish protein concentrate and squid hydrolysate to improve the growth of pompano when fed all‐plant protein diets. The only improvement in performance occurred with the squid hydrolysate. These results demonstrate that using soybean meal, soy protein concentrate and corn gluten meal as the primary protein sources, a plant‐based feed formulation can be developed, but the removal of all animal proteins is not yet feasible.  相似文献   

Hydrolysed salmon meal as a replacement for salmon meal in practical diets for Pacific white shrimp (Litopenaeus vannamei)     

Jingping Guo  Anneleen Swanepoel  Joo Reis  Guillaume Salze  Melanie Rhodes  Donald Allen Davis 《Aquaculture Nutrition》2020,26(2):368-381

A series of growth, feed stability and consumption trials were conducted to evaluate the efficacy of salmon by‐product in practical diets for Pacific white shrimp, Litopenaeus vannamei. This included a salmon by‐product meal (Salmon meal: SM) and a silage hydrolysate (hydrolysed salmon meal: HSM). The basal diet containing 120 g/kg SM was incrementally replaced (0. 25, 50, 75, 100%) by HSM to produce five test diets used in two trials. A sixth diet was included which evaluated gelatin supplementation (trial 1) or pH neutralization (trial 2). In trial 1, each diet was produced using two processing conditions (laboratory extruded and formed with meat grinder) and offered to shrimp in a clear water system. The results demonstrate that up to 50% of the SM can be used to replace with HSM; however, further increases resulted in reduced performance of shrimp. The addition of gelatin reduced leaching but there was limited effect of processing on leaching. There were no detectible effects of pH adjustment of the diets. Results indicated that the growth performance of shrimp has not influenced by HSM up to 60 g/kg to replace 50% of the SM in practical diets; however, higher levels resulted in significant decrease in performance.  相似文献   

Quantitative taurine requirement for juvenile Florida pompano (Trachinotus carolinus) fed soy‐based practical diets     

Guillaume P. Salze  Melanie Rhodes  Donald Allen Davis 《Aquaculture Nutrition》2019,25(2):388-395

Florida pompano Trachinotus carolinus is an important species in which the essentiality of taurine has been demonstrated, yet a quantitative requirement has not been estimated. Two experiments were conducted where a combined twelve diets were formulated with graded levels of taurine (ranging 1.6–41.6 g/kg dry matter) and fed to juvenile pompano (initial weight 7.73 and 4.37 g in trial 1 and 2, respectively). Dose responses were observed in terms of growth, feed efficiency and whole‐body taurine content, but there was no effect on survival. Several regression models were evaluated to determine the most appropriate one to draw conclusions from. A 4‐parameter saturation kinetic model was selected to model feed efficiency, while a 5‐parameter saturation kinetic model fitted the growth data (as thermal‐unit growth coefficient, TGC). A broken‐quadratic model served to estimate a breaking point in the whole‐body taurine content, although it also showed that whole‐body taurine kept increasing even at dietary levels in far excess of the requirement. The dietary taurine requirement was estimated at 2.5 g/kg (2.0–3.3 g/kg, 95% CI, dry matter basis) based on feed efficiency, while TGC was maximized at levels between 4.9 and 31.4 g/kg dietary taurine.  相似文献   

Clinical and biochemical abnormalities in endurance horses eliminated from competition for medical complications and requiring emergency medical treatment: 30 cases (2005–2006)     

C. Langdon Fielding  DVM  DACVECC  ; K. Gary Magdesian  DVM  DACVIM  DACVECC  DACVCP  ; Diane M. Rhodes  ; Chloe A. Meier  Jill C. Higgins  DVM 《Journal of Veterinary Emergency and Critical Care》2009,19(5):473-478

  相似文献   

Postfire Succession in Big Sagebrush Steppe With Livestock Grazing     

Jonathan D. Bates  Edward C. Rhodes  Kirk W. Davies  Robert Sharp 《Strength and Conditioning Journal》2009,62(1):98-110

Prescribed fire in rangeland ecosystems is applied for a variety of management objectives, including enhancing productivity of forage species for domestic livestock. In the big sagebrush (Artemisia tridentata Nutt.) steppe of the western United States, fire has been a natural and prescribed disturbance, temporarily shifting vegetation from shrub–grass codominance to grass dominance. There is limited information on the impacts of grazing to community dynamics following fire in big sagebrush steppe. This study evaluated cattle grazing impacts over four growing seasons after prescribed fire on Wyoming big sagebrush (Artemisia tridentata subsp. Wyomingensis [Beetle & Young] Welsh) steppe in eastern Oregon. Treatments included no grazing on burned and unburned sagebrush steppe, two summer-grazing applications after fire, and two spring-grazing applications after fire. Treatment plots were burned in fall 2002. Grazing trials were applied from 2003 to 2005. Vegetation dynamics in the treatments were evaluated by quantifying herbaceous canopy cover, density, annual yield, and perennial grass seed yield. Seed production was greater in the ungrazed burn treatments than in all burn–grazed treatments; however, these differences did not affect community recovery after fire. Other herbaceous response variables (cover, density, composition, and annual yield), bare ground, and soil surface litter did not differ among grazed and ungrazed burn treatments. All burn treatments (grazed and ungrazed) had greater herbaceous cover, herbaceous standing crop, herbaceous annual yield, and grass seed production than the unburned treatment by the second or third year after fire. The results demonstrated that properly applied livestock grazing after low-severity, prescribed fire will not hinder the recovery of herbaceous plant communities in Wyoming big sagebrush steppe.  相似文献