Assessment of terminal drought tolerance among elite wheat (Triticum aestivum L.) genotypes using selected agronomic and physiological traits

ABSTRACT

The selection response of wheat (Triticum aestivum L.) under water-limited condition can be enhanced through breeding novel genotypes possessing drought-adaptive and yield-related agronomic and physiological traits. The objective of this study was to evaluate terminal drought tolerance among bread wheat genotypes and select superior parents for breeding. Agronomic and physiological responses of 28 wheat lines were assessed under well-watered (WW) and terminal drought (TD) treatments using a 7?×?4 alpha-lattice design under rainout shelter (RS) and glasshouse (GH) environments. Significant (p?≤?0.05) genotype?×?environment interaction effects were observed for number of days to heading (DTH), number of days to maturity (DTM), number of productive tillers per plant (TN), grain yield (GY), thousand kernel weight (TKW), stomatal conductance (SC), leaf canopy temperature (LCT) and chlorophyll content index (CCI) suggesting varied genotypic response under WW and TD treatments. Correlation analysis revealed significant associations TN and GY (r?=?0.67; p?≤?0.001), TKW and GY (r?=?0.72; p?≤?0.001), CCI and GY (r?=?0.39; p?≤?0.05) under TD treatment. Drought tolerant wheat genotypes such as LM100, LM72, LM22 and LM95 are useful for direct cultivation and for developing breeding populations with enhanced yield performance.     

A soil science renaissance

The renaissance was an intellectually-rich period following a period of stasis in the medieval period. Something analogous appears to be currently taking place in soil science where novel approaches to thought are combined with a revival of ideas from the past. Renewed interest in agriculture (food, feed, fuel) and numerous publications have brought soils back onto the global research agenda. The need for up-to-date and fine resolution soil information and the revival of soil research has been highlighted and prioritised in several recent studies by the UN and other international organizations. Soil erosion, nutrient depletion and pollution are key issues that have been brought up in many recent reports - in most cases in relation to environmental degradation, climate change and world-food production. There is also an increased interest in soils in the popular press and media, and soils have entered the policy arena in many countries and several continents. We guestimate that about €3.2 billion is annually spent on soil research in Europe, North America, and some of the main countries in Asia and Oceania. For the global soil science community, there are challenges ahead to address the questions raised in these reports. There is a whole set of new techniques and methodologies in the wings waiting to take centre stage. There is a direct need to educate a new generation of soil scientists and to increase the influx of soil science students in many universities. The soil science community should benefit from the current upsurge in soil science, but the community has to deliver the goods and information that is wanted and much needed.     

The importance and ecology of yeasts in soil

This review focuses on literature pertaining to the interactions of soil yeasts with biotic and abiotic factors in their environment. Soil yeasts not only affect microbial and plant growth, but may also play a role in soil aggregate formation and maintenance of soil structure. Serving as a nutrient source for bacterial, faunal and protistan predators, soil yeasts contribute to essential ecological processes such as the mineralization of organic material and dissipation of carbon and energy through the soil ecosystem. Some soil yeasts may also play a role in both the nitrogen and sulphur cycles and have the ability to solubilize insoluble phosphates making it more readily available for plants. Recently, the potential of soil yeasts as plant growth promoters and soil conditioners has been studied with the goal of using them in the field of sustainable agriculture.     

Mercury volatilization from a floodplain soil during a simulated flooding event

Purpose

Middle-European floodplain soils are often contaminated with mercury (Hg) and periodically flooded. In this study, the influence of a flooding event and subsequent dewatering on the volatilization of elemental Hg and methylated species was investigated in a laboratory experiment.

Material and methods

Undisturbed soil cores were taken from a topsoil (12.1?±?0.75 mg kg^?1 Hg) at the Elbe River in Lower Saxony, Germany. Soil columns were incubated at 20 °C with varying soil moisture (water-saturated for 2 weeks, 95 and 90 % water content for 1 week each), and the redox potential (E_H) was recorded. The gaseous Hg that accumulated in the headspace of the flux chamber of the columns was pumped over cooled traps filled with adsorber material and analyzed by gas chromatography/inductively coupled plasma mass spectrometry for the various Hg species.

Results and discussion

The watering of the soil resulted in a rapid decrease in the E_H and the achievement of strongly reducing conditions (E_H??1 Hg at the beginning to 5.78 μg L^?1 Hg at the end of the experiment. Species analyses revealed that exclusively elemental Hg volatilized. The volatilization rate was between 1.73 and 824 ng m^?2 h^?1 Hg, which is consistent with other studies at the Elbe River.

Conclusions

Even when flooded for a longer period of time, floodplain soils should show neither emission of methylated Hg nor exceptionally high volatilization of elemental Hg.     

Determination of seven glycidyl esters in edible oils by gel permeation chromatography extraction and liquid chromatography coupled to mass spectrometry detection

A method based on a gel permeation chromatography (GPC) extraction procedure combined with an additional cleanup by solid-phase extraction (SPE) on silica gel and liquid chromatography-mass spectrometry (LC-MS) detection has been validated for the analysis of seven glycidyl esters (GEs) including glycidyl laurate, myristate, palmitate, stearate, oleate, linoleate, and linolenate in various edible oils. This method was conjointly developed and validated by two different laboratories, using two different detection systems, a LC time of flight MS (LC-ToF-MS) and a LC triple-quadrupole MS (LC-MS/MS). The extraction procedure allowed targeting low contamination levels due to a highly efficient matrix removal from the 400 mg oil sample loaded on the GPC column and is suitable for routine analysis as 24 samples can be extracted in an automated and reproducible way every 12 h. GPC extraction combined with SPE cleanup and LC-MS/MS detection leads to a limit of quantification in oil samples between 50 and 100 μg/kg depending on the type of glycidyl ester. Recoveries ranged from 68 to 111% (average = 93%). Quantification was performed by automated standard addition on extracts to compensate matrix effects artifacts. To control recoveries of each sample four isotopically labeled GEs ((13)C(3) or (13)C(4)) were included in the method.     

Influence of habitat fragmentation on the genetic structure of Polyommatus coridon (Lepidoptera: Lycaenidae): implications for conservation

Conservation biologists pay increasing attention to the interdependence between habitat structure and genetic patterns of species and to the importance of conserving genetic diversity. A suitable model species for such a study is Polyommatus coridon, a butterfly of dry calcareous grassland. We studied the population genetic structure of 22 western German populations of this species (874 individuals). We observed no congruence between the observed genetic structure and the geographic arrangement of the studied populations. Genetic diversity was slightly higher in large populations than in small populations. Differentiation among populations was weak or even missing. Populations of an area with high habitat density showed no significant differentiation, whereas areas with low habitat densities showed significant genetic differentiation among populations. At present, hierarchical variance analysis revealed no differentiation between four distinguished limestone areas. The combination of all analytical results allow the definition of management units for P. coridon. Conservation measures are proposed from which a large number of rarer species occurring together with P. coridon will benefit.     

Beiträge zur Kenntnis der Vaucheriaceen XVII. überVaucheria prolifera Dangeard 1939 aus dem Harz

Zusammenfassung Vaucheria prolifera Dangeard wird erstmalig für Mitteleuropa an zwei Fundorten im Harz nachgewiesen, in Rohkulturen gehalten und in Ergänzung der Artbeschreibung das Aussehen reifer, lebender Oosporen sowie deren Keimung beschrieben. Die Populationen aus dem Harz zeigen Besonderheiten in der Antheridienausbildung, die in Hinblick auf die beherrschende Rolle der Gametangien in der Systematik der Gattung diskutiert sind.

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Contributions to the knowledge of the vaucheriaceae. XVII.Vaucheria prolifera Dangeard 1939 from the Harz Mountains

Summary A new station forVaucheria prolifera, the first in Middle Europe, is reported. The characters of the living, ripe Oospore and its germination are described. Some peculiar features of the antheridia in this population are discussed under the aspect of the dominating role the Gametangia play in the systematics of the genus.

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Vaucheriaceae. XVII.Vaucheria prolifera Dangeard 1939

, , Vaucheria prolifera. , , . ; , .

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Frau Prof. Dr. H.Sagromsky zum 60. Geburtstag gewidmet.     

Bemerkenswerte Vitalitätsschwächung und Holzzersetzung an Rot-Buchen (Fagus sylvatica) durch den weitgehend unbekannten Schlauchpilz Hypoxylon cohaerens

In the years 2005 and 2006 several declining and recently died beech trees were investigated in a large city park in Dresden. The ascomycete Hypoxylon cohaerens, who is exclusively characterized as a saprophytic fungus by literature, was identified as a conspicuous cause of the disease. The symptoms of the infection, the morphologically and physiologically characteristics of the fungus in situ and in vitro as well as the factors of predisposition are presented in the article. Since H. cohaerens attains pathological importance and can be mistaken for some other ascomycetes, the distinguishing marks to related species are described. The changed importance of the fungus is evaluated for practice.     

Substituted alpha-(phenylhydrazono)phenylacetonitrile derivatives. Part 2: Synthesis and biological activity of pro-pesticides

Pro-pesticides of alpha-(2,6-dichloro-4-trifluoromethylphenylhydrazono)-4-nitrophenylacetonitrile have been prepared and tested against mite and insect pests. Variations in potency and spectrum were observed depending on the choice of cleavable pro-moiety. Cleavage of the pro-moiety was demonstrated in one case by measuring the rate of increase in the uncoupling activity using a mitochondrial preparation. Irradiation experiments have demonstrated a rapid isomerisation of the planar Z isomer to the E isomer, which is reversible.