Combined application of nitrogen and phosphorus to enhance nitrogen use efficiency and close the wheat yield gap on varying soils in semi‐arid conditions     

Therese M. McBeath  Vadakattu V. S. R. Gupta  Rick S. Llewellyn  Sean D. Mason  Christopher W. Davoren  Raymond L. Correll  Ben Jones  Anthony M. Whitbread 《Journal of Agronomy and Crop Science》2019,205(6):635-646

A primary driver of the wheat yield gap in Australia and globally is the supply of nitrogen (N) and options to increase N use efficiency (NUE) are fundamental to closure of the yield gap. Co‐application of N with phosphorus (P) is suggested as an avenue to increase fertiliser NUE, and inputs of N and P fertiliser are key variable costs in low rainfall cereal crops. Within field variability in the response to nutrients due to soil and season offers a further opportunity to refine inputs for increased efficiency. The response of wheat to N fertiliser input (0, 10, 20, 40 and 80 kg N ha^‐1) under four levels of P fertiliser (0, 5, 10 and 20 kg P ha^?1) was measured on three key low rainfall cropping soils (dune, mid‐slope and swale) across a dune‐swale system in a low rainfall semi‐arid environment in South Australia, for three successive cropping seasons. Wheat on sandy soils produced significant and linear yield and protein responses across all three seasons, while wheat on a clay loam only produced a yield response in a high rainfall season. Responses to P fertiliser were measured on the sandy soils but more variable in nature and a consistent effect of increased P nutrition leading to increased NUE was not measured.  相似文献   

An experimental test of the habitat amount hypothesis reveals little effect of habitat area but transient or indirect effects of fragmentation on local species richness     

With  Kimberly A.  Payne  Alison R. 《Landscape Ecology》2021,36(9):2505-2517

Landscape Ecology - The habitat amount hypothesis (HAH) posits that local species richness is driven more by the amount of habitat in the surrounding landscape than by local patch size or habitat...  相似文献   

Grassland fragmentation affects declining tallgrass prairie birds most where large amounts of grassland remain     

Herse  Mark R.  With  Kimberly A.  Boyle  W. Alice 《Landscape Ecology》2020,35(12):2791-2804

Landscape Ecology - Habitat fragmentation can exacerbate the negative effects of habitat loss for some species. Mitigating fragmentation is difficult, however, because population responses depend...  相似文献   

Identification of a Group of Novel y-Gliadin Genes     

QI Peng-fei  WEI Yu-ming  Ouellet Therese  CHEN Qing  WANG Zhao  WEI Zhen-zhen  ZHENG You-liang 《农业科学学报》2014,13(2):290-298

γ-Gliadins are an important component of wheat seed storage proteins. Four novel γ-gliadin genes （Gli-ngl to Gli-ng4） were cloned from wheat （Triticum aestivum） and Aegilops species. The novel γ-gliadins were much smaller in molecular size when compared to the typical γ-gliadins, which was caused by deletion of the non-repetitive domain, glutamine-rich region, 3＂ part of the repetitive domain, and 5＇ part of the C-terminal, possibly due to illegitimate recombination between the repetitive domain and the C-terminal. As a result, Gli-ngl and Gli-ng4 only contained two and three cysteine residues, respectively. Gli-ngl, as the representative of novel γ-gliadin genes, has been sub-cloned into an Escherichia coli expression system. SDS- PAGE indicated that the both cysteine residues of Gli-ngl could participate in the formation of intermolecular disulphide bonds in vitro. Successful cloning of Gli-ngl from seed cDNA of T. aestivum cv. Chinese Spring suggested that these novel γ-gliadin genes were normally transcribed during the development of seeds. Phylogenic analysis indicated that the four novel γ-gliadin genes had a closer relationship with those from the B （S） genome of wheat.  相似文献   

Public sector soybean (Glycine max) breeding: Advances in cultivar development in the African tropics     

Godfree Chigeza  Steve Boahen  Melaku Gedil  Eric Agoyi  Hapson Mushoriwa  Nicholas Denwar  Therese Gondwe  Abush Tesfaye  Alpha Kamara  Oladeji Emmanuel Alamu  David Chikoye 《Plant Breeding》2019,138(4):455-464

Formal public sector soybean breeding in Africa spans over four decades, and it was initiated by the International Institute of Tropical Agricultural (IITA). As the demand of soybean continues to outstrip production, strategic projects such the Tropical Legume (TL) were initiated, in which the main goal was to enhance the productivity of soybean in the farmers’ fields in Sub‐Saharan Africa. One of the strategies to enhance the productivity of soybean in the farmers’ fields is through developing and deploying improved soybean varieties in the target countries. Through the TL I and TL II projects, a number of varieties were released in the target countries, Kenya, Nigeria, Malawi and Mozambique by employing participatory variety selection (PVS). This review provides highlights of the achievements made by IITA breeding programme and insights of what needs to be done to enhance yield improvement for soybean in Africa using demand‐driven breeding approaches.  相似文献   

Early weaning and postweaning nutritional management affect feedlot performance of angus x simmental heifers and the relationship of 12th rib fat and marbling score to feed efficiency     

Wertz E  Berge LL  Walker PM  Faulkner DB  McKeith FK  Rodriguez-Zas S 《Journal of animal science》2001,79(7):1660-1669

Early-weaned Angus x Simmental heifers were used to evaluate the effects of postweaning nutritional management on feedlot performance, carcass merit, and the relationship of intramuscular and subcutaneous fat deposition to the feed efficiency among heifers fed for a high-quality market. Sixteen heifers were weaned at 73+/-5.5 d of age and grazed on endophyte-infected tall fescue for 18 mo before entering the feedlot (early-weaned-P). Eighty heifers from the following year's calf crop were weaned at 71+/-5.5 d of age and allowed either ad libitum access to a 25% concentrate diet (early-weaned-25C) or limit-fed a 90% concentrate diet (early-weaned-90C) to achieve a similar ADG. Following a 119-d growing period, 16 early-weaned-90C and 16 early-weaned-25C calves were paired based on BW and growth rate and individually fed during the finishing period along with the early-weaned-P heifers. Ultrasound measurements of s.c. and i.m. fat were recorded at approximately 60-d intervals throughout the finishing period. Feed efficiency was regressed against s.c. and i.m. fat, and i.m. fat was regressed on s.c. fat. Despite a similar ADG, early-weaned-90C calves gained more efficiently (P < or = 0.05) in the feedlot than early-weaned-25C calves. Heifers finished as yearlings tended (P < or = 0.10) to gain faster but gained less efficiently (P < or = 0.01) than early-weaned-90C heifers finished as calves. The rate of s.c. and i.m. fat deposition was similar between early-weaned-90C and early-weaned-25C heifer calves. The calves were grouped together for comparison to yearlings. Feed efficiency decreased quadratically (P < or = 0.01) as s.c. fat cover increased. The rate at which feed efficiency decreased relative to increasing s.c. fat cover was similar regardless of age at feedlot entry. However, heifers finished as calves gained more efficiently (P < or = 0.01) than yearlings at any given fat thickness. Feed efficiency decreased linearly (P < or = 0.01) as i.m. fat increased among heifers finished as calves. Additionally, heifers finished as calves deposited i.m. fat at a faster rate relative to s.c. fat (P < or = 0.01) than yearlings. These data suggest that heifers finished as calves produce high-quality carcasses with less s.c. fat cover while gaining more efficiently than heifers finished as yearlings.  相似文献   

Plasma ascorbic acid concentrations in healthy dogs     

Wang S  Berge GE  Sund RB 《Research in veterinary science》2001,71(1):33-35

Using a highly sensitive and selective analytical method and careful stability control, plasma concentrations of ascorbic acid were determined in German Shepherd Dogs, Labrador Retrievers and Siberian Huskies, a total 99 animals. Mean concentration was 35.9 micromol l(-1)(range 18.2-50.7), and no significant variation was observed neither between breeds nor between females and males. These and previous reported data on plasma ascorbic acid levels in dogs are discussed in the light of methodological aspects.  相似文献   

Assessing antibiotic resistance in fecal Escherichia coli in young calves using cluster analysis techniques     

Berge AC  Atwill ER  Sischo WM 《Preventive veterinary medicine》2003,61(2):91-102

This study uses cluster analysis techniques to describe the antibiotic susceptibility patterns seen in calf fecal Escherichia coli (E. coli). Cohorts of 30 dairy calves at six farms were sampled at 2-week intervals during the pre-weaning period. At each sampling occasion five fecal E. coli isolates per calf were analyzed for antibiotic susceptibility to 12 antibiotics using the disk diffusion method. All isolates had a profile consisting of the aggregate measured inhibition zone size for each of the evaluated antibiotics. Several cluster analytic algorithms were assessed to partition the E. coli isolates. For our data, Ward's minimum variance method met the objectives of the study. Relative to the number of possible combinations of resistance clusters, a parsimonious set of 14 patterns was developed. This set of E. coli isolates exhibited a limited set of resistance patterns to the different antibiotics indicating that certain resistance genes may be linked.  相似文献   

Echinococcus multilocularis (Cestoda,Taeniidae) in Red foxes (Vulpes vulpes) in northern Belgium     

Vervaeke M  Dorny P  Vercammen F  Geerts S  Brandt J  Van Den Berge K  Verhagen R 《Veterinary parasitology》2003,115(3):257-263

The first record of the tapeworm Echinococcus multilocularis (Cestoda, Taeniidae) in Red foxes (Vulpes vulpes) in northern Belgium is described. Between 1996 and 1999, 237 dead foxes were examined for the presence of this tapeworm using the intestinal scraping technique. Four foxes (1.7%) were found to be infected with E. multilocularis and showed medium to very high parasitic burdens. Three infected foxes originated from the south of the study area and the fourth animal came from the north of the study area near the border with The Netherlands. These findings are discussed in relation to the high endemicity of E. multilocularis in southern Belgium and to the increased distribution of the Red fox (V. vulpes) in northern Belgium during the last two decades.  相似文献   

Die Differenzierunggas-, rauch- und staubförmiger Immissionen bei landwirtschaftlichen,gartenbaulichen und forstwirtschaftlichen Kulturen     

H. Berge 《Journal of pest science》1972,45(6):84-86

Summary The differentiation between acute, direct chronic and indirect chronic immissions caused by atmospheric pollution brought about by emissions having the nature of gas, smoke and dust is described. Several positive examples are quoted to the question whether indirect chronic immissions are possible without damage to growth up, yield and/or production.A differentiation has value for autotrophic and heterotrophic life forms:1. Insignificant immissions in the animate world prevail when autotrophic/heterotrophic life forms are not adversely affected, as compared with their condition in their usual situation and surroundings, i. e. when: their anatomical/morphological development, their function, their efficiency, their powers of propagation, their immunity to disease, their longevity and their physiological function and/or psychical well-being are not impaired.2. Considerable immissions in the animate world prevail when the development, function, efficiency, powers of propagation, immunity to disease and/or general well-being of autotrophic/ heterotrophic life forms, as compared with their condition in their usual situation and surroundings, are affected by reversible physiological/ psychical disturbances (direct and indirect chronic immissions) but when their longevity remains unaffected and when anatomical/morphological anomalies, changes and/or damage (acute immissions) do not occur.3. Severe immissions in the animate world prevail when the development, function, efficiency, power of propagation, immunity to disease, longevity and/or general well-being of autotrophic/heterotrophic life forms, as compared with their condition in their usual situation and surroundings, is affected or interrupted by repeated or irreversible physiological/psychical disturbances (direct and indirect chronic immissions), whereby, under certain circumstances, limited but typical anatomical/ morphological anomalies, changes and/or damage (acute immissions) occur to separate organic parts.4. Excessive immissions in the animate world prevail when the development, function, efficiency, power of propagation, immunity to disease, longevity and/or general well-being of autotrophic/ heterotrophic life forms, as compared with their condition in their usual situation and surroundings, are prevented or ended by repeated or irreversible physiological changes or by psychical disturbances (direct and indirect chronic immisssions), whereby, under certain circumstances, some organs or complete organisms suffer extended and typical anatomical/morphological anomalies, changes and/or damage (acute immissions).  相似文献