Bernd Honermeier

Intraspecific diversity and relationship between subspecies of Origanum vulgare revealed by comparative AFLP and SAMPL marker analysis

The genus Origanum is often referred to as an under-utilized taxon because of its complex taxonomy. Origanum vulgare L., the most variable species of the genus, is a spice and medicinal herb that is characterized by high morphological diversity (six subspecies). In this study, the relative efficiencies of two PCR-based marker approaches, amplified fragment length polymorphism (AFLP) and selectively amplified microsatellite polymorphic loci (SAMPL), were used for comparable genetic diversity surveys and subspecies discrimination among 42 oregano accessions. Seven assays each of AFLP and SAMPL markers were utilized. Effective multiplex ratio (EMR), average heterozygosity (Hav-p), marker index (MI), and resolving power (RP) of the primer combinations were calculated for the two marker systems. UPGMA and Structure analysis along with PCoA plots derived from the binary data matrices of the two markers depicted the genetic distinction of accessions. Our results indicate that both marker systems are suitable but SAMPL markers are slightly more efficient in differentiating accessions and subspecies than AFLPs.

Use of AFRCWHEAT2 to predict the development of main stem and tillers in winter triticale and winter wheat in North East Germany

Abstract Winter triticale (cv. Grado) and winter wheat (cv. Taras) were grown in Rostock, Germany (54.2°N) for 5 years (1985–91) each with up to four sowing dates. Shoot apex development of the main stem and the two most developed tillers was observed by sampling eight plants every 3–10 days. The developmental submodel of the AFRCWHEAT2 simulation model was tested to predict the developmental events: emergence, start of floral initiation, double ridge, start of floret initiation, end of spikelet initiation and anthesis. Anthesis of main shoots was observed 8 days earlier for triticale than for wheat which was explained by an earlier start of reproductive development in triticale than in wheat. Variation in the dates of phenological events was greater for floral initiation and double ridges than for floret initiation and anthesis in both cereals. Dates of the early stages of development varied more in triticale than in wheat and more for main shoots than for tillers. For both species, standard deviations of the differences between observed and model predicted dates of phenological events were larger among developmental stages than between cultivars. Prediction of the early stages of development (floral initiation and double ridge) was poor for both species. The beginning of floret initiation and anthesis were simulated more accurately. We suggest that progress in simulating the development of cereals is more limited by lack of knowledge about plant physiology, rather than by the process of modelling. Better quantification of the vernalization requirements of different species is identified as an important topic for future work. Developmental parameters calculated for main shoots could also be used to closely predict the development rates of tillers. Differences between the development rates of main shoots and tillers were explained by the weather conditions each tiller group experienced and not by differences in their physiological responses to climatic factors. More research is needed to describe differences in development and vernalization requirements of a tiller when compared with that of a main shoot.

Einfluss des Anbaus von transgenem herbizidresistentem Raps auf das Agrar-Ökosystem

ZusammenfassungIn einer zweijährigen Studie zur Untersuchung der ökologischen Auswirkungen der Herbizidresistenztechnik bei Raps wurden auf einem Brandenburger Ackerbaustandort (Güterfelde, Landkreis Potsdam Mittelmark) Parzellenfeldversuche mit zwei basta(glufosinat)-resistenten Sommerrapshybriden und einer bastaresistenten Winterrapslinie und deren isogener Ausgangsform durchgeführt. Es zeigte sich, dass mit der Bastaanwendung einige tolerante Unkrautarten, wie z. B. Viola arvensis selektiert werden. Dies könnte in einseitigen Herbizidrotationen zur Entwicklung herbizidtoleranter Wildpflanzenpopulationen beitragen. Sowohl die Untersuchung der mikrobiellen Biomasse und der Bodenatmung als auch die Analyse der Rhizobium leguminosarum-Population ließen deutliche Wirkungen der verwendeten Rapssorte und der Herbizidapplikation erkennen. Jedoch waren Effekte, die eindeutig auf die transgene Veränderung des Rapses zurückzuführen sind, nicht nachweisbar. Das neue Herbizidmanagement führte somit prinzipiell zu keinen anderen Wirkungen auf die Bodenmikroflora als die konventionelle Herbizidanwendung. Auch bei den blütenbesuchenden Insekten war kein abweichendes Verhalten erkennbar. In den Untersuchungen zum Pollentransfer konnte gezeigt werden, dass Rapspollen durch Wind und Insekten über mehrere Kilometer transportiert werden, wodurch eine Übertragung der Herbizidresistenz auch auf relativ weit entfernte Kreuzungspartner möglich ist. Aufgrund des hohen Auskreuzungspotentials des Rapses und noch unzureichender Kenntnisse zu möglichen Langzeitwirkungen der Herbizidresistenztechnik wird vorgeschlagen, einen Anbau herbizidresistenter Sorten innerhalb eines geeigneten Kontrollsystems zu überwachen.AbstractIn a two-year study, the impact of transgenic herbicide-resistant oilseed rape on the agroecosystem was analysed. The field trials located in northeastern Germany (state of Brandenburg) were planted with two Basta-resistant spring oilseed rape hybrids and a Basta-resistant winter oilseed rape, as well as their non-transgenic counterparts. Results indicated the selective effect of the herbicide Basta (glufosinate) on several weeds like Viola arvensis, which under high selection pressure might contribute to the development of herbicide tolerant weed populations. The investigation of the soil microbial biomass and the soil basal respiration as well as the analysis of the Rhizobium leguminosarum-population demonstrated the distinct impacts of the rape variety and the herbicide application. Effects, however, clearly caused by transgenic modification could not be found. Therefore, compared to the conventional herbicide treatment, the new herbicide management did not result in a modified impact on the soil microflora. In the same way, the behaviour of flower-visiting insects was not influenced. Concerning the distances of pollen transfer, rape-pollen was shown to be distributed over several kilometres. The outcrossing of transgenes needs to be considered in further studies. Moreover, possible long-term effects of the new herbicide management should be included in an appropriate ecological control system.

Correlations between Genetic, Morphological, and Chemical Diversities in a Germplasm Collection of the Medicinal Plant Origanum vulgare L.

In total, 42 accessions of Origanum vulgare L., mostly originating from Europe, were evaluated, to detect molecular, quantitative morphological, and chemotype polymorphisms and to discover possible correlations between them. Twelve traits related to morphological characteristics were measured. The components in the essential oils were identified by GC/MS analysis, and the oil contents of 18 major compounds were determined. A total of 477 molecular polymorphisms including 214 AFLP (amplified fragment length polymorphism) and 263 SAMPL (selectively amplified microsatellite polymorphic loci) were used for genotyping. Euclidean distances of morphological and chemotypic data and genetic distances (1 – Dices similarity) of molecular markers were compared by applying Mantel tests to ascertain the congruencies between them. A relatively high correlation between chemotypic patterns and genetic markers was identified, while a lower correlation was found between the morphological and genetic matrices. Pairwise analyses of correlation among all traits showed that the stem diameter was correlated to the essential‐oil yield and the carvacrol content. Cluster analysis, population inference, and principal component analysis revealed a broad genetic and chemical variation among the accessions. The knowledge of these diversities, found in this study, will allow a plant improvement of Origanum vulgare related to pharmaceutical and spice uses.

Statistical analysis of the associations between phenolic monoterpenes and molecular markers, AFLPs and SAMPLs in the spice plant Oregano

Summary Introduction: Molecular markers are the examples of the contribution of genome technology to medicinal plant breeding through marker-assisted selection (MAS) for pharmaceutical quality. Objective: Forty-two accessions of Origanum vulgare L. originating from Europe were evaluated to detect genomic and chemotypic polymorphisms and to discover possible associations between them. Methods: A total of 477 molecular polymorphisms including 214 AFLP (Amplified Fragment Length Polymorphism) and 263 SAMPL (Selectively Amplified Microsatellite Polymorphic Loci) were used for genotyping. Components in the essential oils were identified and quantified by gas chromatography (GC) and two major compounds (two economically important monoterpenes: carvacrol and thymol) were investigated. Results: Based on results, a relatively high correlation between chemotypic patterns and genetic markers was identified. Associations between traits of interest for essential oils (carvacrol and thymol content) and genetic markers were tested using five statistical methods including three General Linear Model (GLM) and two unified Mixed Linear Model (MLM) approaches. Significant associations were found for 3 AFLP and 20 SAMPL with three key traits including essential oil yield, carvacrol and thymol content. Conclusion: These associations can constitute a useful starting point for marker-assisted selection. Therefore, the results provide the basis for molecular breeding of O. vulgare for pharmaceutical purposes.

Impact of highly varying seeding densities on grain yield and yield stability of winter rye cultivars under the influence of delayed sowing under sandy soil conditions

ABSTRACT The objective of this study was to determine how to establish high and stable yields of winter rye under the impact of highly varying seeding densities and delayed sowing date. A field trial with three winter rye cultivars (two population cultivars and one F1 hybrid) was conducted on a sandy site over a period of three years. The results showed that seeding density, cultivar choice, and annual weather conditions are important factors impacting the yield variability of winter rye. Higher seeding densities led to higher and slightly more stable yields of winter rye. Moreover, a cultivar-adapted seeding date seemed to exploit yield potential advantageously. Interestingly, all three cultivars showed better yield stability with a two-week delay in seeding date. This study suggests that cultivar choice and management practices such as modulation of seeding date and seeding density play an important role in improving the grain yield and yield stability of winter rye.

Variety choice in crop production for climate change adaptation: Farmer evidence from Germany

The objective of this study was to understand what particular crop variety requirements farmers were demanding in the context of climate change adaptation. A broad-based survey was used to collect primary data from 515 farmers. The majority of farmers interviewed perceived climatic change impacts on crop production, with more than half stating that they would rely on a locally adapted variety selection. The respondents identified yield stability, yield performance, and drought tolerance as being particularly important variety properties. In selecting varieties, their own experience, exchanges with colleagues, and recommendations from the State Plant Varieties Offices were identified as being important sources of information. The research highlights a need to reflect farmers’ demands in official variety recommendations such as plant breeding. This would help support the choice of varieties in agricultural practice and reduce crop production risks in regard to climate change risk.

Content and composition of essential oil of four Origanum vulgare L. accessions under reduced and normal light intensity conditions

The variation in the chemical composition and content of the essential oil was examined in four Origanum vulgare accessions (Ov): 1- Origanum vulgare L. ssp. vulgare (=Ovu), 2- Origanum vulgare L. ssp. hirtum (Link) letswaart (=Ohi), 3- Origanum vulgare L. ssp. viride (Boiss.) Hayek (=Ovi) and 4- Origanum vulgare L. ssp. viride (Boiss.) Hayek × O. majorana L. (=Oxm), growing under reduced (26%) and normal light intensity. Altogether, 64 compounds representing 98.95% of the total oil were identified. Reduced light had a minor effect on the composition of essential oil. It decreased the content of p-cymene in Ohi and increased the sabinene content in Oxm herb samples. The essential oil of Ovu in both samples was mainly composed of trans-sabinene hydrate, β-caryophellene and germacrene D. The major components of essential oil of Ohi were thymol and carvacrol followed by γ-terpinene and p-cymene. Herb samples had a considerably higher amount of essential oil than leaf samples. In herb extracts of Ovi, cymyl compounds such as p-cymene, thymol and γ-terpinene were dominant. Oxm was characterized by several monoterpenes with low concentrations including γ-terpinene, sabinene cis-b-ocimene and carvacrol methyl ether. The results of the current study suggest a chemical toleration of the evaluated accessions to the applied light reduction. Furthermore, a full investigation of essential oil profiles of Origanum vulgare accessions is presented.

Modelluntersuchungen zur einschätzung der potentiellen n‐freisetzung nach kleegrasumbruch

Nach Klee‐ sowie Kleegrasumbruch kann der Boden uber relativ rasch mineralisierbaren Stickstoff verfugen. In 123 Tagen wurden unter Laborbedingungen bis zu 280 kg/ha entsprechende Min‐N ‐Mengen freigelegt. Art und Nutzungsdauer der Bestande bestimmten die Hohe der N‐Freigaben. Reine Rotkleeansaaten bewirkten die groste Min‐N‐Bereitstellung, eine Differenzierung zwischen den Ansaatpartnern wurde nicht beobachtet. Umgebrochene Klee‐ und Kleegrasbestande konnen, der ausgewiesenen Min‐N‐Bereitstellung zufolge, ein erhebliches okologisches Gefahrdungspotential darstellen, das uber die Vermeidung unproduktiver N‐Verluste durch geeignete acker‐ und pflanzenbauliche Masnahmen unbedingt zu minimieren ist.

Continuous cropping of endangered therapeutic plants via electron beam soil-treatment and neutron tomography

Various medicinal plants are threatened with extinction owing to their over-exploitation and the prevalence of soil borne pathogens. In this study, soils infected with root-rot pathogens, which prevent continuous-cropping, were treated with an electron beam. The level of soil-borne fungus was reduced to ≤0.01% by soil electron beam treatment without appreciable effects on the levels of antagonistic microorganism or on the physicochemical properties of the soil. The survival rate of 4-year-old plant was higher in electron beam-treated soil (81.0%) than in fumigated (62.5%), virgin (78%), or untreated-replanting soil (0%). Additionally, under various soils conditions, neutron tomography permitted the monitoring of plant health and the detection of root pathological changes over a period of 4–6 years by quantitatively measuring root water content in situ. These methods allow continual cropping on the same soil without pesticide treatment. This is a major step toward the environmentally friendly production of endangered therapeutic herbs.