BIOBREED – a new project on marker assisted population breeding in wheat with resistance to common bunt

The paper describes the BIOBREED project

Two new denarius hoards from the island of Lolland

Since 2009, a number of Roman denarii from the 1st, 2nd and 3rd centuries AD have been discovered on the Danish island of Lolland. Among them, two denarius hoards contained, respectively, approximately 110 and 46 coins. Previously, only few imported objects from the Late Roman Iron Age were known from Lolland, in stark contrast to the large amount of imported prestigious artefacts from the preceding Early Roman Iron Age. These denarius finds shed new light on an otherwise poorly understood time period in the region, especially with regard to the possible networks of trade and exchange in which the local population took part. As the presence of denarii in an Iron Age context is often interpreted as a sign of contacts ultimately extending beyond the bounds of present-day Denmark, this article explores the possibility that the in casu denarius finds from Lolland point to the existence of local settlements participating in the flow of elite exchange during the 3rd and possibly also 4th centuries AD

Feedback control of cerebellar learning

The ability to anticipate future events and to modify erroneous anticipatory actions is crucial for the survival of any organism. Both theoretical and empirical lines of evidence implicate the cerebellum in this ability. It is often suggested that the cerebellum acquires “expectations” or “internal models”. However, except in a metaphorical sense, the cerebellum, which consists of a set of interconnected nerve cells, cannot contain “internal models” or “have expectations”. The aim of this thesis is to untangle these metaphors by translating them back into neurophysiological cause and effect relationships. This task is approached from within the paradigm of classical conditioning, in which a subject, through repeated presentations of a conditional stimulus, followed by an unconditional stimulus, acquires a conditioned response. Importantly, the conditioned response is timed so that it anticipates the unconditioned response. Available neurophysiological evidence suggests that Purkinje cells, in the cerebellar cortex, generate the conditioned response. In addition, Purkinje cells provide negative feedback to the IO, which is a relay for the unconditional stimulus, via the nucleo-olivary pathway. Purkinje cells can therefore regulate the intensity of the signal derived from the unconditional stimulus, which, in turn, decides subsequent plasticity. Hence, as learning progresses, the IO signal will become weaker and weaker due to increasing negative feedback from Purkinje cells. Thus, in an important sense, learning induced changes in Purkinje cell activity constitute an “expectation” or “anticipation” of a future event (the unconditional stimulus), and, consistent with theoretical models, future learning depends on the accuracy of this expectation. Paper 1 in this thesis show that learned changes in Purkinje cells influences subsequent IO activity. The second paper show that, depending on the number of pulses it contains, the signal from the IO to the Purkinje cells can either cause acquisition or extinction. In the third paper we present evidence that can potentially help explain overexpectation, a behavioral phenomenon, which have for long been elusive. Collectively these papers advance our understanding of the feedback mechanisms that govern cerebellar learning and it proposes a potential solution to some long standing behavioral conundrums

El papel de la OTAN y su evolución en la era de la globalización

Discurso del secretario general de la OTAN pronunciado en Madrid el 10 de septiembre de 2010, en un acto organizado por el Real Instituto Elcano

Quasi-Species and Aggregate Dynamics

At an early stage in pre-biotic evolution, groups of replicating molecules must coordinate their reproduction to form aggregated units of selection. Mechanisms that enable this to occur are currently not well understood. In this paper we introduce a deterministic model of primitive replicating aggregates, proto-organisms, that host populations of replicating information carrying molecules. Some of the molecules promote the reproduction of the proto-organism at the cost of their individual replication rate. A situation resembling that of group selection arises. We derive and analytically solve a partial differential equation that describes the system. We find that the relative prevalence of fast and slow replicators is determined by the relative strength of selection at the aggregate level to the selection strength at the molecular level. The analysis is concluded by a preliminary treatment of finite population size effects.Comment: 6 page

Association Mapping for Common Bunt Resistance in Wheat

Common bunt, caused by Tilletia caries and T. foetida, is a fungal disease of wheat world wide. Infection, occurring via seed borne teliospores, is generally controlled by the application of seed treatments prior to sowing. Farming systems like organic agriculture with a very limited range of organic seed treatments available rely heavily on common bunt resistance genes within wheat. In the framework of the BIOBREED project an association study in winter wheat was conducted, aiming at the identification of genetic loci linked to resistance towards common bunt in wheat. 152 European wheat cultivars were phenotyped for their resistance reaction for the two consecutive years 2011/12 at Agrologica research station at Mariager. Infection was scored as percent infected ears. The scorings were log-transformed to fit a disease scoring scale ranging from 1 to 9. The association analysis was performed for each year separately as well as for the mean scoring of the two years. The wheat cultivars were genotyped with DArT markers, yielding 1832 polymorphic loci. The association analysis was conducted using the computer program Genstat, with the ASReml module. Minimun allele frequency for the association analysis was set to 0.07. 13 out of the total of1832 marker in our study were linked to common bunt resistance in wheat (-log10(P) >3). These marker are located on 8 out of the 21 wheat chromosomes. Comparisons of these findings with other published results are difficult since only very little is known about the chromosomal location of common bunt resistance genes/QTL in wheat. Chromosome 2B was previously reported to carry gene(s) for common bunt resistance. Findings of our analysis are in accordance with this: 4 of the linked marker resided on this chromosome. Further, another two linked marker were found on chromosome 2D, another chromosome previously reported to carry common bunt resistance genes. Our study shows the possibilities of finding makers linked to common bunt resistance in wheat, and of using these markers for marker assisted selection of wheat cultivars tailored for the needs of organic agriculture

Common bunt resistant wheat composite cross populations

Utilising diverse populations instead of single line varieties is expected to lead to a number of advantages in cereal production. These include reduced epidemics of plant diseases, improved weed competition and better exploitation of soil nutrients, resulting in improved yield stability. However, a number of challenges must be met before diverse wheat populations can be introduced into commercial wheat production: one of these is the development of breeding technologies based on mass selection which enable breeders and farmers to improve specific traits in populations and maintain diversity at the same time. BIOBREED is a project started in Denmark in 2011 to meet these challenges for wheat population breeding. The project is focusing on the development of tools and methods for mass selection of traits relevant for organic and low input production, where it is expected that the highest benefits of utilizing diverse populations can be achieved. BIOBREED focuses on three main aspects of wheat population breeding for organic and low input production systems: i) common bunt (caused by Tilletia caries) resistance, ii) selection for improved protein content and iii) the influence on population diversity of different selection pathways. Selection for common bunt resistance in wheat composite cross populations 33 crosses were made between 23 common bunt resistant winter wheat varieties in order to generate two populations. Progeny of all crosses was bulked in the F 3 to constitute the first population Pop.No.Sel. Prior to the creation of the second population Pop.Sel, the F 3 of the parental crosses was sown as head-rows with common bunt infection. Only lines that showed resistance to common bunt were used to create Pop.Sel. in generation F 4 . Afterwards the two populations were grown with and without inoculation with common bunt in order to i) select for bunt resistance and ii) to be able to compare the effect on diversity of this selection step. Preliminary results show a higher level of common bunt resistance in Pop.Sel in the first year. Single seed sorting for protein content Prior to sowing the F 5 seed of the population Pop.Sel, the seed were sorted individually for protein content using a BoMill IQ Grain Quality Sorter 1002S. The fraction of seeds containing the 10% highest and another fraction containing the 10% lowest protein content were selected. The four populations, Pop.No.Sel, Pop.Sel, and Pop.Sel.high. Protein and Pop.Sel.low.Protein and the parental lines were sown in a randomized complete block yield trial at two locations in Denmark in order to assess their yield and quality parameters such as protein content and baking quality of the parents and there derived populations. Results are expected in the summer 2013. Diversity of wheat composite cross populations. The practical question of “how much diversity is needed in populations?” has not been answered yet. BIOBREED will aim to to quantify the levels of diversity in wheat composite cross populations after the different selection steps i) cultivation with and without common bunt inoculum, and ii) sorting for single protein content. In a fist attempt SSR markers will be used to describe the influence these different selection pathways will have on the population diversity. 90 SSR markers—about two markers per chromosome arm—will be used to describe the initial genetic diversity of the 23 parental lines. F 6 seed of the different populations will be analysed with the same markers and population diversity after different selection pathways will be quantified