Determinants of barley grain yield in drought-prone Mediterranean environments

The determinants of barley grain yield in drought-prone Mediterranean environments have been studied in the Nure x Tremois (NT) population. A large set of yield and other morpho-physiological data were recorded in 118 doubled haploid (DH) lines of the population, in multi-environment field trials (18 site-year combination). Agrometeorological variables have been recorded and calculated at each site too. Four main periods of barley development were considered, vegetative, reproductive early and late grain filling phases, to dissect the effect on yield traits of the growth phases. Relationships between agrometeorological variables, grain yield (GY) and its main components (GN and GW) were also investigated by correlation. Results firstly gave a clear indication of the involvement of water consumption in determining GY and GW (r2=0.616, P=0.007 and r2=0.703, P=0.005, respectively) calculated from sowing to the early grain filling period, while GN showed its highest correlation with the total photothermal quotient (PQ) calculated for the same period (r2=0.646, P=0.013). With the only exception of total PQ calculated during the vegetative period, all significant correlations with GY were associated to water-dependent agrometeorological parameters. As a second result, the NT segregating population allowed us to weight the amount of interaction due to genotypes over environments or to environments in relation to genotypes by a GGE analysis; 47.67% of G+GE sum of squares was explained by the first two principal components. Then, the introduction of genomic information at major barley genes regulating the length of growth cycle allowed us to explain patterns of adaptation of different groups of NT lines according to the variants (alleles) harbored at venalization (Vrn-H1) in combination with earliness (Eam6) genes. The superiority of the lines carrying the Nure allele at Eam6 was confirmed by factorial ANOVA testing the four possible haplotypes obtained combining alternative alleles at Eam6 and Vrn-H1. Maximum yield potential and differentials among the NT genotypes was finally explored through Finlay-Wilkinson model to interpret grain yield of NT genotypes together with yield adaptability (Ya), as the regression coefficient bi; Ya ranged from 0.71 for NT77 to 1.20 for NT19. Lines simply harboring the Nure variants at the two genes behaved as highest yielding (3.04 t ha\u20131), and showed the highest yield adaptability (bi=1.05). The present study constitutes a starting point towards the introduction of genomic variables in agronomic models for barley grain yield in Mediterranean environments

A Combined Field/Laboratory Method for Assessment of Frost Tolerance with Freezing Tests and Chlorophyll Fluorescence

Recent progress in genotyping allows for studies of the molecular genetic basis of cold resistance in cereals. However, as in many other fields of molecular genetic analysis, phenotyping for high numbers of genotypes is still a major bottleneck. The use of chlorophyll fluorescence measurements as an indicator for freezing stress is a well established and rapid method for evaluation of frost tolerance. In order to extend the applicability of this technique beyond plants grown under controlled conditions in growth chambers and sacrificed for the test, here we study its applicability for leaves harvested from field trials during winter and subjected to freezing tests. Such an approach allows for simultaneous studies of the advancement of cold hardening and other components of winter survival apart from frost tolerance. It is shown that cutting or senescence of cut leaves does not have adverse effects on the outcome of subsequent freezing stress tests. The time requirements for field sampling and laboratory testing on high numbers of genotypes allow for the application of the proposed approach for genotyping/phenotyping studies

Carbon Isotope Fractionation in Plant Respiration

Carbon isotopes have long been used to dissect metabolic pathways. More recently, stable isotopes have become an important tool in modeling global fluxes in the biosphere, and notably CO2 isofluxes. The accuracy of these models relies partly on the knowledge of fractionations associated with each individual flux component. This has led to the observation that carbon isotope fractionation occurs during respiration in plants, and exhibits large temporal and spatial variations. Despite important advances in the area, metabolic features underlying such variability remain to be fully elucidated. The present chapter summarizes available data on plant respiratory fractionation, and presents a critical discussion about the metabolic origin of its variation, in the light of recent developments in understanding the compartmentation and plasticity of plant respiration. It emphasizes the need for refining existing frameworks, and points out knowledge gaps that need to be filled so as to achieve a more quantitative modeling of respiratory fractionation

European winegrowers' perceptions of climate change impact and options for adaptation

Sous presse Accepté 8 juillet 2008International audienceA questionnaire on the perception of climate change and the impact of climate change was distributed among winegrowers in France, Germany, and Italy. These countries are located in three macro-climatic regions that experienced different patterns of climatic change in the twentieth century Atlantic, transition to Continental and Mediterranean. The majority of winegrowers perceived changing climatic conditions in the last few decades. The characterization of these changes is consistent with results obtained by the analysis of long-term trends in climatic records. The winegrowers noted impacts on harvestable quantities (mainly in Italy), must quality, and risks of pests and diseases. The majority of respondents (66%) indicated an impact on wine quality, which was perceived as quality improvement in 55% of the cases. Perceived impacts on pests and diseases were reported in 56% of the responses. A strong majority of this group (80%) also reported increasing threats. Perceived climatic change and its noticeable impacts has led to growing interest in adaptation options, combined with a need for more information, among winegrowers. Thus, the transfer of technical knowledge from scientific research to practice is necessary for adaptation. Plans for adaptation by a change of wine varieties were reported with substantially different results among the regions. A majority of German growers said they would consider changing varieties to adapt to warming temperatures, while only a minority of the Italian and French growers said they would consider such changes. However, readiness to adopt adaptation measures is correlated with the degree of changes already planned, independent of climatic change

Foreword (to the special issue of Rapid Communications in Mass Spectrometry, 2009, Vol. 23)

N/AJRC.D.3-Knowledge Transfer and Standards for Securit

(Preface) Selected papers from the 2nd Joint European Stable Isotope Users Meeting (JESIUM) 31 August¿5 September 2008, Presqu¿île de Giens, France

The first Joint European Stable Isotope Users group Meeting (JESIUM) was organised in 2004 in Vienna by Rebecca Hood-Nowotny with the participation of the Stable Isotope Network Austria (SINA). Following the success of this first meeting, the French association of stable isotopes (SFIS) was proud to organise the second JESIUM in Giens (France) in 2008, under the coordination of Jaleh Ghashghaie, and with the collaboration of the other European national associations/networks of stable isotopes (BASIS Benelux, ESIR Eastern and central Europe, GASIR Germany, SIMSUG UK, and SINA Austria). The objectives of JESIUM are to bring together scientists with a broad range of interests in stable isotopes, to encourage communication across disciplines and country boundaries, to provide the opportunity to discuss theoretical and methodological difficulties, and to exchange ideas about howtechniques might be transferred to other areas of research. The papers in the current and the following issues cover reports on progress in applications in medicine and environmental control. Further results presented at JESIUM are published in Rapid Communications in Mass Spectrometry, 2009, Vol. 23, Issue 16 and Acta Oecologica, 2009, Vol. 35, Issue 6.JRC.D.3-Knowledge Transfer and Standards for Securit

Influence of heterogeneous landscapes on computed green-up dates based on daily AVHRR NDVI observations

International audienc

Preface

International audienc

Relationship between taproot morphological traits, carbon isotope composition and grain yield in safflower

International audienceThe purpose of this study was to determine to what extent root characteristics, other than the taproot length, contribute to high grain yield and/or high water use efficiency (WUE) in safflower. A greenhouse trial was conducted using four safflower accessions (USDA6, USDA23, USDA29 and VARTOUG) with contrasting yield and WUE. A randomised complete block design was chosen, which included a typical (control) and a drought stress (withholding watering at the pre-flowering stage) treatments. The carbon isotope composition (C-13) as an estimate of WUE, taproot diameter (D-TR), diameter and number of secondary roots (D-SR and N-SR, respectively), biomass of the upper section of the taproot (BMTR-up) as well as grain yield (GY) and its components were measured. Our results revealed that N-SR could be involved in drought adaptation of USDA23, with N-SR increasing significantly (p=0.045) by 27% under drought stress in this accession. BMTR-up was the only taproot trait correlated to GY and/or WUE, however the nature of the correlation was different for control and stressed plants. BMTR-up was significantly (p=0.01) and negatively correlated with C-13 (r=-0.63) but had no correlation with GY (r=0.23) in control plants. In contrast, BMTR-up was significantly (p=0.03) and positively correlated with GY (r=0.56) but not with C-13 (r=0.23) under drought stress conditions. This finding suggests that, in the absence of drought conditions selecting safflower for a lower biomass in the upper section of the taproot may lead to high WUE, without affecting the yield

Using ecological and life-history characteristics for projecting species' responses to climate change

Assessing the impact of climate change on range dynamics is difficult in the absence of large-extent distribution data. We developed a novel two-step approach as an instrument for biodiversity risk assessment. First, we established relationships between modelled loss of occupied grid cells (‘range loss’, R2=0.29), or gain of currently unoccupied grid cells (‘range gain’, R2=0.30), for 195 plant species with distributional data under the A1FI climate change scenario up to 2080, and ecological and life history traits (life form, leaf persistence, ecological strategy, pollen vector, Ellenberg indicator values and characteristics derived from species’ ranges). Secondly, we used the resulting coefficients to predict climatic sensitivity for 688 plant species without spatially explicit distributional information. The models predicted range losses of 34±20 % (mean±standard deviation) and range gains of 3±4 %. Specifically, measures of species’ distribution, such as range size, were significantly related to both range loss and range gain. Other traits associated with range loss (e.g. life form, number of floristic zones) were not necessarily related to range gain (instead related to Ellenberg temperature indicator), indicating that two distinct sets of ecological processes govern range expansion and contraction. We found interaction effects between moisture indicator values and life form for range loss, and between moisture and temperature indicator values for range gain. The responses of species to climate change are complex and context dependent. Thus, our results highlight the importance of incorporating trait interactions in models to assess risks of climate change. &nbsp