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

The paper describes the BIOBREED project

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

Strategic use of virulence pattern to develop genetic markers for resistance to common bunt (Tilletia caries) in wheat

When assesssing races of common bunt for virulens pattern within a region, it is important to take into account that collected spores may represent a diverse population of different virulence races. When screening spores on a differential set of wheat lines with known resistance genes, a low infection rate on a resistant wheat variety does not necessarily demonstrate that virulence is absent in the spore collection, but could be a sign that virulence is present, but only present in a low frequency among the spores. If just a few spores within a spore sample are indeed virulent, they may infect some plants and from there multiply the virulence quite rapidly next years. Previous studies have shown that virulence against most resistance genes were present in Denmark after purifying races of common bunt (Tilletia caries) on resistant varieties. So far, only wheat differential varieties with Bt4, Bt6, Bt9, Bt11 and Bt12 cannot be infected with bunt races purified from Danish collections [1, and later own unpublished data]. Virulence against Bt4, Bt6 and Bt9 has been found in other European studies [2], and Bt11 may not be only one gene but a combination of at least two genes [3]. Therefore, Bt12 seems to be the only gene for which virulence have not been found in European population of common bunt. This leads to the conclusion that if resistance breeding shall safely control common bunt in wheat, we need not only one effective gene, but a combination of pyramided genes. Since it is very difficult to test if a resistant line has only one gene or more genes, the most effective tool to achieve this at present are genetic markers. Using Genome Wide Association Studies (GWAS) to find QTLs and markers for the major resistance genes in wheat have so far led to only few commercial useful markers. Till now, only markers for Bt9 [6] and Bt10 are used in practice, but a marker for Bt12 [4] and Blizzard [7] have also been found. One of the problems in developing markers for bunt resistance have been that spores used in GWAS trials have been divers or unknown in virulence, and that phenotypic results not distinguishes between different resistance genes. Therefore, the most successful studies have used segregating populations of single crosses where the resistance gene is known on before hand [5]. In the LIVESEED project, we have the ambition to develop genetic markers on several different resistance genes at the same time. We will do so by testing segregating populations of several different crosses between varieties with 7 different resistance genes, and infect them with 7-11 different virulence races of common bunt able to distinguish between the resistance genes. A total of 300 varieties will be pheno- and genotyped. Using this experimental design, we attempt during 2018 and ‘19 to develop markers for Bt1, Bt2, Bt5, Bt7, Bt13, BtZ and Quebon-resistance, and hopefully also a couple of minor QTLs

Marker assisted breeding and mass selection of 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

The Impact of Tillage System for Small-Grain Pasture Establishment on the Performance of Growing Beef Calves in Arkansas

In the United States, governmental regulations mandate the improvement of farming practices to improve environmental quality. There is a requirement to reduce the siltation of waterways, soil carbon losses, and nutrient runoff along the Mississippi River Delta. The use of small-grain forages by grazing cattle offers real opportunities to produce high-quality forage for cattle production during the winter and spring months. No-till and reduced tillage practices developed primarily for grain production may offer environmental and economic solutions for both grain farmers and cattle producers. Producers are slow to adopt conservation tillage practices because of a perceived risk of reduced production. The objective of this project was to compare conventional tillage to reduced tillage and no-till systems for production of small-grain forage for grazing livestock

Conditional versus unconditional forecasting with the New Area-Wide Model of the euro area

In this paper we examine conditional versus unconditional forecasting with a version of the New Area-Wide Model (NAWM) of the euro area designed for use in the context of the macroeconomic projection exercises at the European Central Bank (ECB). We first analyse the out-of-sample forecasting properties of the estimated model from 1999 to 2005 by comparing its unconditional forecasts with those obtained from a Bayesian VAR with a steady-state prior as well as na¨ıve forecasts. Model-based forecasts that are conditioned on differing information sets are then studied and evaluated through, for instance, modesty statistics to assess the relevance of the Lucas critique. In contrast to other studies in the literature, we condition on a fairly large set of policy-relevant variables. Furthermore, we consider conditioning information that partially, albeit not fully determine the future path of the observed variables, but which restrict the channels through which they can be affected

Conditional versus unconditional forecasting with the New Area-Wide Model of the euro area

In this paper we examine conditional versus unconditional forecasting with a version of the New Area-Wide Model (NAWM) of the euro area designed for use in the context of the macroeconomic projection exercises at the European Central Bank (ECB). We first analyse the out-of-sample forecasting properties of the estimated model from 1999 to 2005 by comparing its unconditional forecasts with those obtained from a Bayesian VAR with a steady-state prior as well as na¨ıve forecasts. Model-based forecasts that are conditioned on differing information sets are then studied and evaluated through, for instance, modesty statistics to assess the relevance of the Lucas critique. In contrast to other studies in the literature, we condition on a fairly large set of policy-relevant variables. Furthermore, we consider conditioning information that partially, albeit not fully determine the future path of the observed variables, but which restrict the channels through which they can be affected

The chemical composition of red giants in 47 Tucanae I: Fundamental parameters and chemical abundance patterns

Context: The study of chemical abundance patterns in globular clusters is of key importance to constrain the different candidates for intra-cluster pollution of light elements. Aims: We aim at deriving accurate abundances for a large range of elements in the globular cluster 47 Tucanae (NGC 104) to add new constraints to the pollution scenarios for this particular cluster, expanding the range of previously derived element abundances. Methods: Using tailored 1D LTE atmospheric models together with a combination of equivalent width measurements, LTE, and NLTE synthesis we derive stellar parameters and element abundances from high-resolution, high signal-to-noise spectra of 13 red giant stars near the tip of the RGB. Results: We derive abundances of a total 27 elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ru, Ba, La, Ce, Pr, Nd, Eu, Dy). Departures from LTE were taken into account for Na, Al and Ba. We find a mean [Fe/H] = $-0.78\pm0.07$ and $[\alpha/{\rm Fe}]=0.34\pm0.03$ in good agreement with previous studies. The remaining elements show good agreement with the literature, but the inclusion of NLTE for Al has a significant impact on the behaviour of this key element. Conclusions: We confirm the presence of an Na-O anti-correlation in 47 Tucanae found by several other works. Our NLTE analysis of Al shifts the [Al/Fe] to lower values, indicating that this may be overestimated in earlier works. No evidence for an intrinsic variation is found in any of the remaining elements.Comment: 22 pages, 16 figures. Accepted for publication in A&