Organic plant breeding

This report was presented at the UK Organic Research 2002 Conference. To a major extent, organic farming depends currently on plant and animal varieties that have been bred for non-organic farming and that are often not suited to organic production. This position is inconsistent with a holistic approach to organic agriculture. Organically-bred plant varieties are needed to develop both the potential of organic agriculture and its integrity. A first attempt at developing a concept for organic plant breeding methodology has been proposed. A novel approach to breeding for organic production has also been started. Further development needs a parallel approach to animal breeding for organic systems

Historical Lassa Fever Reports and 30-year Clinical Update

Five cases of Lassa fever have been imported from West Africa to the United States since 1969. We report symptoms of the patient with the second imported case and the symptoms and long-term follow-up on the patient with the third case. Vertigo in this patient has persisted for 30 years

A participatory approach to variety trials for organic systems

A participatory research methodology was used to compare the performance of UK wheat varieties under organic conditions. Plots of three breadmaking winter wheat varieties (Hereward, Solstice and Xi19) and a mixture (1:1:1) of the varieties were grown at 19 UK farms in two seasons (2003/04 and 2004/05). Meas-urements were taken of growth habit, yield and grain quality. Grain yields in both seasons showed significant site by variety interactions, although the variation among sites was greater than among varieties in both instances. Wheat grown at Western sites was significantly shorter and higher-yielding than that grown at Eastern sites in 2003/04 but significantly taller in 2004/05. As with grain yield, greater variation among site than variety was found in the Hagberg Falling Number and protein concentra-tion results in both seasons. The results from the two years of trials illustrate the variability of organic systems and the difficulty in selecting a single variety suitable for organic farms

Diversifikationsstrategien für das Management der Kraut-und Knollenfäule der Kartoffel

Fazit: Die bisherigen Ergebnisse deuten auf eine extreme Sortenabhängigkeit in den epidemiologischen Effekten von Diversifikationsstrategien hin. Außerdem spielt die Variabilität des Befallsdruckes selbst innerhalb eines Feldes eine kritische Rolle. Für die Auswertung von Daten muß deshalb die räumliche Verteilung des Befalles viel stärker mit entsprechenden statistischen Modellen in Betracht gezogen werden. Die Ergebnisse aus den Streifenexperimenten sind analog den Ergebnissen aus den Sortenmischungen und deuten darauf hin, daß Kartoffeln extrem empfindlich auf Konkurrenz sowohl verschiedener Sorten als auch Arten reagieren. Um Diversifikationsstrategien sinnvoll einsetzen zu können, sollten als erstes die Reaktionen von Sorten auf andere Sorten und Arten quantifiziert werden, um geeignete Sorten zu identifizieren. Es könnte auch ein Zuchtziel für die ökologische Landwirtschaft werden, die Konkurrenzfähigkeit mehr in den Vordergrund zu stellen. Dies wäre auch in Bezug auf Unkrautunterdrückung unter Umständen von Interesse. Um ein Streifenexperiment sinnvoll auszuwerten, muß der Ertrag und Befall der Außen- und Innenreihen von Parzellen getrennt erfaßt werden. Für die Beurteilung des Gesamtergebnisses kann dann nicht einfach auf Hektarerträge hochgerechnet werden sondern es muß das Gesamtsystem in Betracht gezogen werden. Insgesamt können Diversifikationsstrategien den Krankheitsdruck reduzieren. Dies belegen auch Beobachtungen aus China, wo der Streifenanbau von Kartoffeln und Mais zu bis zu 40% Reduktion im Befall mit P. infestans und damit zu einer Reduktion im Fungizideinsatz geführt hat (Z. Youyong, 2002, pers. Mitteilung)

Evolutionary breeding of wheat for low input systems

Genetically diverse Composite Cross Populations (CCPs) may be useful in environmentally variable low-input systems as an alternative to pure varieties. They are formed by assembling seed stocks with diverse evolutionary origins, recombining these stocks by hybridisation, bulking the F1 progeny, and subsequent natural selection of the progeny in suc-cessive natural cropping environments. CCPs derived from either 10 high yielding parents (YCCPs), 12 high quality parents (QCCPs), or all 22 parents (YQCCPs), were grown at four sites (2 organic, 2 conventional) in the UK. The YCCPs out yielded the QCCPs, which had higher protein concentrations and Hagberg falling numbers. Although the CCPs performed within the range of the parents, they often performed better than the mean of the parents

Natural selection towards wild-type in composite cross populations of winter wheat

Most of our crops are grown in monoculture with single genotypes grown over wide acreage. An alternative approach, where segregating populations are used as crops, is an exciting possibility, but outcomes of natural selection upon this type of crop are not well understood. We tracked allelic frequency changes in evolving composite cross populations of wheat grown over ten generations under organic and conventional farming. At three generations, each population was genotyped with 19 SSR and 8 SNP markers. The latter were diagnostic for major functional genes. Gene diversity was constant at SSR markers but decreased over time for SNP markers. Population differentiation between the four locations could not be detected, suggesting that organic vs. non-organic crop management did not drive allele frequency changes. However, we did see changes for genes controlling plant height and phenology in all populations independently and consistently. We interpret these changes as the result of a consistent natural selection towards wild-type. Independent selection for alleles that are associated with plant height suggests that competition for light was central, resulting in the predominance of stronger intraspecific competitors, and highlighting a potential trade-off between individual and population performanc

Lattice dynamics and correlated atomic motion from the atomic pair distribution function

The mean-square relative displacements (MSRD) of atomic pair motions in crystals are studied as a function of pair distance and temperature using the atomic pair distribution function (PDF). The effects of the lattice vibrations on the PDF peak widths are modelled using both a multi-parameter Born von-Karman (BvK) force model and a single-parameter Debye model. These results are compared to experimentally determined PDFs. We find that the near-neighbor atomic motions are strongly correlated, and that the extent of this correlation depends both on the interatomic interactions and crystal structure. These results suggest that proper account of the lattice vibrational effects on the PDF peak width is important in extracting information on static disorder in a disordered system such as an alloy. Good agreement is obtained between the BvK model calculations of PDF peak widths and the experimentally determined peak widths. The Debye model successfully explains the average, though not detailed, natures of the MSRD of atomic pair motion with just one parameter. Also the temperature dependence of the Debye model largely agrees with the BvK model predictions. Therefore, the Debye model provides a simple description of the effects of lattice vibrations on the PDF peak widths.Comment: 9 pages, 11 figure

Discovery of a compact gas-rich DLA galaxy at z = 2.2: evidences for a starburst-driven outflow

We present the detection of Ly-alpha, [OIII] and H-alpha emission associated with an extremely strong DLA system (N(HI) = 10^22.10 cm^-2) at z=2.207 towards the quasar SDSS J113520-001053. This is the largest HI column density ever measured along a QSO line of sight, though typical of what is seen in GRB-DLAs. This absorption system also classifies as ultrastrong MgII system with W2796_r=3.6 A. The mean metallicity of the gas ([Zn/H]=-1.1) and dust depletion factors ([Zn/Fe]=0.72, [Zn/Cr]=0.49) are consistent with (and only marginally larger than) the mean values found in the general QSO-DLA population. The [OIII]-Ha emitting region has a very small impact parameter with respect to the QSO line of sight, b=0.1", and is unresolved. From the Ha line, we measure SFR=25 Msun/yr. The Ly-a line is double-peaked and is spatially extended. More strikingly, the blue and red Ly-a peaks arise from distinct regions extended over a few kpc on either side of the star-forming region. We propose that this is the consequence of Ly-a transfer in outflowing gas. The presence of starburst-driven outflows is also in agreement with the large SFR together with a small size and low mass of the galaxy (Mvir~10^10 Msun). From the stellar UV continuum luminosity of the galaxy, we estimate an age of at most a few 10^7 yr, again consistent with a recent starburst scenario. We interpret the data as the observation of a young, gas rich, compact starburst galaxy, from which material is expelled through collimated winds powered by the vigorous star formation activity. We substantiate this picture by modelling the radiative transfer of Ly-a photons in the galactic counterpart. Though our model (a spherical galaxy with bipolar outflowing jets) is a simplistic representation of the true gas distribution and velocity field, the agreement between the observed and simulated properties is particularly good. [abridged]Comment: 15 pages, 18 figures, 4 tables, accepted for publication in Astronomy and Astrophysic

Detection of Extended He II Reionization in the Temperature Evolution of the Intergalactic Medium

We present new measurements of the temperature of the intergalactic medium (IGM) derived from the Lyman-alpha forest over 2.0 < z < 4.8. The small-scale structure in the forest of 61 high-resolution QSO spectra is quantified using a new statistic, the curvature, and the conversion to temperature calibrated using a suite of hydrodynamic simulations. At each redshift we focus on obtaining the temperature at an optimal overdensity probed by the Lyman-alpha forest, T(Delta), where the temperature is nearly a one-to-one function of the curvature regardless of the slope of the temperature-density relation. The median 2-sigma statistical uncertainty in these measurements is 8 per cent, though there may be comparable systematic errors due to the unknown amount of Jeans smoothing in the IGM. We use our T(Delta) results to infer the temperature at the mean density, T0. Even for a maximally steep temperature-density relation, T0 must increase from ~8000 K at z ~ 4.4 to >~12000 K at z ~ 2.8. This increase is not consistent with the monotonic decline in T0 expected in the absence of He II reionization. We therefore interpret the observed rise in temperature as evidence of He II reionization beginning at z >~ 4.4. The evolution of T0 is consistent with an end to He II reionization at z ~ 3, as suggested by opacity measurements of the He II Lyman-alpha forest, although the redshift at which T0 peaks will depend somewhat on the evolution of the temperature-density relation. These new temperature measurements suggest that the heat input due to the reionization of He II dominates the thermal balance of the IGM over an extended period with Delta_z >~ 1.Comment: 19 pages, 15 figures, accepted to MNRA

Prevalence of comorbidities in rheumatoid arthritis and evaluation of their monitoring: results of an international, cross-sectional study (COMORA)

Background: Patients with rheumatoid arthritis (RA) are at increased risk of developing comorbid conditions.&lt;p&gt;&lt;/p&gt; Objectives: To evaluate the prevalence of comorbidities and compare their management in RA patients from different countries worldwide.&lt;p&gt;&lt;/p&gt; Methods Study design: international, cross-sectional. Patients: consecutive RA patients. Data collected: demographics, disease characteristics (activity, severity, treatment), comorbidities (cardiovascular, infections, cancer, gastrointestinal, pulmonary, osteoporosis and psychiatric disorders).&lt;p&gt;&lt;/p&gt; Results: Of 4586 patients recruited in 17 participating countries, 3920 were analysed (age, 56±13 years; disease duration, 10±9 years (mean±SD); female gender, 82%; DAS28 (Disease Activity Score using 28 joints)–erythrocyte sedimentation rate, 3.7±1.6 (mean±SD); Health Assessment Questionnaire, 1.0±0.7 (mean±SD); past or current methotrexate use, 89%; past or current use of biological agents, 39%. The most frequently associated diseases (past or current) were: depression, 15%; asthma, 6.6%; cardiovascular events (myocardial infarction, stroke), 6%; solid malignancies (excluding basal cell carcinoma), 4.5%; chronic obstructive pulmonary disease, 3.5%. High intercountry variability was observed for both the prevalence of comorbidities and the proportion of subjects complying with recommendations for preventing and managing comorbidities. The systematic evaluation of comorbidities in this study detected abnormalities in vital signs, such as elevated blood pressure in 11.2%, and identified conditions that manifest as laboratory test abnormalities, such as hyperglycaemia in 3.3% and hyperlipidaemia in 8.3%.&lt;p&gt;&lt;/p&gt; Conclusions: Among RA patients, there is a high prevalence of comorbidities and their risk factors. In this multinational sample, variability among countries was wide, not only in prevalence but also in compliance with recommendations for preventing and managing these comorbidities. Systematic measurement of vital signs and laboratory testing detects otherwise unrecognised comorbid conditions.&lt;p&gt;&lt;/p&gt