The potato breeding programme in Denmark

Summary Frem 1948 onward there has been a marked increase in potato breeding work in Denmark. This is due to the fact that the Danish Agriculture Potato Fund was established in this year and its proceeds are devoted to the advancement of potato breeding in Denmark. The fund owns the Potato Breeding Station at Vandel, near Vejle, and this together with the State Research Station at Tylstrup are the only places in Denmark where potato breeding is carried out. Breeding of ware varieties constitutes a great part of the work, although the breeding of varieties used for fodder and industrial purposes is also an important aspect of the work. The quality and yield capacity of the new varieties are very important considerations, although the present work of breeding also aims at finding varieties which are only slightly affected by late blight and common scab. As the conditions governing the production of virus-free seed potatoes, do not constitute any serious problem in Denmark, little attention has been paid to the finding of virus-resistant varieties, except on the case of special varieties intended for export. The station in Vandel owns a fairly large collection of wild and cultivated species of potatoes. Three of the most promising varieties from Vandel will be sent for an official test as from 1958.

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Zusammenfassung Seit dem Jahre 1948 ist die Arbeit der Kartoffelzüchtung in D?nemark ganz bedeutend erweitert worden, da in diesem Jahre der ?Kartoffelfonds der Landwirtschaft? gegründet wurde, dessen Ertrag in erster Linie die Kartoffelzüchtung D?nemarks stützen soll. Der Fonds besitzt die Zuchtstation bei Vandel. Zusammen mit der Versuchsstation in Tylstrip im Besitz des Staates, ist es die einzigen Stelle in D?nemark, wo Kartoffelzüchtung betrieben wird. Die Züchtung von Speisekartoffeln ist sehr wichtig, aber auch die Arbeit mit Futter- und Fabrikkartoffeln ist von gr?sster Bedeutung. Eigenschaften, wie Ertrag und Qualit?t der neuen Kartoffelsorten, sind von besonderer Wichtigkeit, aber eines der Ziele der jetzigen Züchtungsarbeit ist, Kartoffelsorten zu finden, die nicht so stark von Krautf?ule und Kartoffelschorf angegriffen werden. Da die Bedingungen für die Erzeugung von virusfreien Saatkartoffeln in D?nemark sehr günstig sind, hat man nicht viel Interesse daran, virusresistente Sorten zu züchten, mit Ausnahme von Kartoffelsorten für Export. Auf der Station in Vandel befindet sich eine gr?ssere Sammlung von wilden und kultiviertenSolanum-Arten, die einer der Mitarbeiter der Station aus verschiedenen südamerikanischen Staaten mitgebracht hat. Drei neue Sorten haben bei den vorl?ufigen Prüfungen gute Resultaten ergeben.

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Résumé A partir de l'année 1948 l'ocuvre sélectionnaire de la pomme de terre au Danemark a pris un large essor. C'est que dans cette année fut institutée la ?Caisse Agricole de la Pomme de terre?, dont les fonds sont réservés en premier lieu à soutenir l'oeuvre sélectionnaire de la pomme de terre au Danemark. La ?Caisse? exploite la Station d'expérimentation à Vandel qui, ensemble avec la Station d'essais à Tylstrup-également un institut de l'Etat-sont les seules institutions au Danemark où l'on se voue à l'oeuvre sélectionnaire de la pomme de terre. La culture de la pomme de terre de consommation revêt une importance particulière, tout comme d'ailleurs celle des pommes de terre fourragères et industrielles. Les propriétés des nouvelles variétés, telles que rendement et qualité, sont très importantes, mais l'un des objectifs de l'oeuvre sélectionnaire de nos jours est de créer des variétés de pommes de terre résistantes au mildiou et à la gale commune. Etant donné que les conditions de production pour plants de pommes de terre exempts de toute contagion virologique sont très favorables au Danemark, on s'intéresse peu à la culture de variétés résistantes aux maladies à virus, sauf les variétés de pommes de terre destinées à l'exportation. A la Station à Vandel on dispose d'une collection assez riche de variétésSolanum sauvages et cultivées en provenance de différents états américains et approtées par l'un des chercheurs de cet Institut. Trois variétés ont fait l'objet d'expériences entreprises à titre provisoire, et elles ont donné de bons résultats.

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Lecture held at Lund, August 1957     

Near infrared spectra indicate specific mutant endosperm genes and reveal a new mechanism for substituting starch with (1→3,1→4)-β-glucan in barley

Near Infrared Reflectance spectroscopy was tested as a screening method to characterise high lysine mutants from a barley collection by classification through Principal Component Analysis (PCA). Mean spectra of the samples within each cluster identified gene-specific patterns in the 2270–2360 nm region. The characteristic spectral signatures representing the lys5 locus (Risø mutants 13 and 29) were found to be associated with large changes in percentage of starch and (1→3,1→4)-β-glucan. These alleles compensated for a low level of starch (down to 30%) by a high level of (1→3,1→4)-β-glucan (up to 15–20%), thus, maintaining a constant production of polysaccharides at 50–55%, within the range of normal barley.The spectral tool was tested by an independent data set with six mutants with unknown polysaccharide composition. Spectral data from four of these were classified within the high (1→3,1→4)-β-glucan BG lys5 cluster in a PCA. Their high (1→3,1→4)-β-glucan and low starch content was verified. It is concluded that genetic diversity such as from gene regulated polysaccharide and storage protein pathways in the endosperm tissue can be discovered directly from the phenotype by chemometric classification of a spectral library, representing the digitised phenome from a barley gene bank.     

Starved bacteria retain their size but lose culturability - Lessons from a 5000 years old undisturbed A-horizon

The vast majority of soil bacteria are unable to form visible colonies on agar media. One hypothesis is that unculturable soil bacteria are dwarf cells that may either be small starved forms derived from larger species or represent inherently small species. We test the hypotheses that cells of extremely starved soil bacterial communities are smaller and less culturable than cells of bacterial communities from a richer soil, and that culturability is related to cell size by comparing an extremely starved community from a 5200-year-old A-horizon buried under a burial mound with a community from a modern agricultural A-horizon.We serially filtered cell suspensions through filters with successively smaller pore sizes (0.8 μm, 0.6 μm and 0.4 μm) and assessed total cell number and culturability, i.e. the ability to form colonies on two types of agar media, in each size fraction. Cell size distributions were assessed in unfiltered suspensions. Average cell size was only moderately reduced in the starved community, where culturability was low for all size classes. In contrast, culturability was much higher in the modern community, where culturability decreased dramatically with decreasing cell sizes.     

Societal Costs of Late Blight in Potato and Prospects of Durable Resistance Through Cisgenic Modification

In the European Union almost 6 Mha of potatoes are grown representing a value of close to €6,000,000,000. Late blight caused by Phytophthora infestans causes annual losses (costs of control and damage) estimated at more than €1,000,000,000. Chemical control is under pressure as late blight becomes increasingly aggressive and there is societal resistance against the use of environmentally unfriendly chemicals. Breeding programmes have not been able to markedly increase the level of resistance of current potato varieties. New scientific approaches may yield genetically modified marker-free potato varieties (either trans- and/or cisgenic, the latter signifying the use of indigenous resistance genes) as improved variants of currently used varieties showing far greater levels of resistance. There are strong scientific investments needed to develop such improved varieties but these varieties will have great economic and environmental impact. Here we present an approach, based on (cisgenic) resistance genes that will enhance the impact. It consists of five themes: the detection of R-genes in the wild potato gene pool and their function related to the various aspects in the infection route and reproduction of the late blight causing pathogen; cloning of natural R-genes and transforming cassettes of single or multiple (cisgenic) R-genes into existing varieties with proven adaptation to improve their value for consumers; selection of true to the wild type and resistant genotypes with similar qualities as the original variety; spatial and temporal resistance management research of late blight of the cisgenic genetically modified (GM) varieties that contain different cassettes of R-genes to avoid breaking of resistance and reduce build-up of epidemics; communication and interaction with all relevant stakeholders in society and transparency in what research is doing. One of the main challenges is to explain the different nature and possible biological improvement and legislative repercussions of cisgenic GM-crops in comparison with transgenic GM-crops. It is important to realize that the present EU Directive 2001/18/EC on GM crops does not make a difference between trans- and cisgenes. These rules were developed when only transgenic GM plants were around. We present a case arguing for an updating and refinement of these rules in order to place cisgenic GM-crops in another class of GM-plants as has been done in the past with (induced) mutation breeding and the use of protoplast fusion between crossable species.     

Development of bio-assays and screening for resistance to beet armyworm (Spodoptera Exigua Hübner) in Allium cepa L. and its wild relatives

The beet armyworm (Spodoptera exigua Hübner)is the most important pest in tropical Alliumcultivations. All shallot (Allium cepa L. group Aggregatum) cultivars are susceptible to this pest. Therefore accessions from three wild Alliumspecies, namely A. galanthum Kar. et Kir., A. fistulosum L. and A. royleiStearn, next to A. cepa L. were used to screen for resistance. First of all, a reliable bio-assay had to be developed. To this end transparent plastic cages with in total 5 plants of one accession per cage were placed on per lite in a heated greenhouse. Five 3-day old larvae were inoculated on each plant. Eight days after inoculation the number of surviving larvae per cage and the mean fresh weightper larva was determined. The lowest larval survival (36%) was found on A. roylei. This was not, however, significantly different from other Allium accessions. Significant differences were found in the fresh weight per larva fed on different Allium accessions. The larvae survived on A. roylei had a very low fresh weight (10.3 mg per larva), while those on an accession of A. fistulosum had the highest fresh weight (45.1 mg per larva). The larval fresh weight on A. roylei was lower than all the other accessions except from the tropical shallot cultivar Bawang Bali. To check whether or not a toxic compound was involved in the resistance present in A. roylei, tenaccessions from four Allium species were screened. Five 3-day old larvae were inoculated on regularly replaced leaf material of each accession ofAllium species. No significant differences were found in mean fresh weight per larva and mean survival of larvae among different accessions. There were also no significant differences in pupal weight and developmental time. All larvae became pupae 10 days after inoculation. The data indicate that there is no toxic compound present in A. roylei. These results are underlined by the observation in the greenhouse bio-assay that A. roylei plants were equally damaged by the beet armyworm compared to otherAllium species. The results obtained so far therefore suggest that introduction of resistance to S. exigua via the exploitation of variation for resistance to the beet armyworm in A. roylei is unclear and that genetic engineering using Cry sequences could provide a way forward. This revised version was published online in July 2006 with corrections to the Cover Date.     

Surgical treatment of a large congenital cavernous haemangioma on the thorax of a foal

A 3‐day‐old male foal was presented with a fluctuant 25 × 15 cm mass on the thorax. The mass had increased in size since birth. The mass did not respond to conservative treatment consisting of aspiration of serohaemorrhagic contents and compression bandages, and it was therefore surgically removed when the foal was approximately 2½ weeks. A histopathological diagnosis of cavernous haemangioma was made. Healing progressed without complications despite a large surgical wound left to heal by second intention. Recurrence was not observed during the 1.5‐year follow‐up period.     

Growth and Ionic Content of Quinoa Under Saline Irrigation

Drought and salinity are the most important abiotic stresses that affect plant's growth and productivity. The aim of the present work was to evaluate the effect of salt and water deficit on water relations, growth parameters and capacity to accumulate inorganic solutes in quinoa plants. An irrigation experiment was carried out in 2009 and 2010 in the Volturno river plain. Three treatments irrigated with fresh water (Q100, Q50 and Q25) and three irrigated with saline water (Q100S, Q50S and Q25S) were tested. For saline irrigation, water with an electrical conductivity of 22 dS m^?1 was used. Actual evapotranspiration (ET_a), water productivity (WP), biomass allocation, relative growth rate (RGR), net assimilation rate (NAR), specific leaf area, leaf area ratio and ions accumulation of quinoa plants were evaluated. WP and plant growth were not influenced by saline irrigation, as quinoa plants incorporated salt ions in the tissues (stems, roots, leaves) preserving seed quality. Treatment with a reduction in the irrigation water to 25 % of full irrigated treatment (Q25) caused an increase in WP and a reduced dry matter accumulation in the leaves. Quinoa plants (Q25) were initially negatively affected by severe drought with RGR and NAR reduction, and then, they adapted to it. Quinoa could be considered a drought tolerant crop that adapt photosynthetic rate to compensate for a reduced growth.     

Comparison of methods to reduce dioxin and polychlorinated biphenyls contents in fishmeal: extraction and enzymatic treatments

Methods to remove dioxins and polychlorinated biphenyls (PCBs) from fishmeal were investigated and compared. The tested methods include (i) lowering the fat content and simultaneously the level of toxic contaminants using either organic solvents or (ii) lowering the fat content using protease and (iii) removal of dioxins and PCBs using either oil extraction or (iv) breakdown of dioxin and PCBs using oxidoreductase. The results showed that the organic solvents tested (ethanol, isopropanol, and isohexane) were efficiently lowering the oil content of the fishmeal by 80%. However, the treated fishmeal has a low fat content and may contain traces of solvent. The protease alcalase was not as efficient as the solvent extraction and only removed approximately 30% of the oil but presented the advantage of being a mild process. Other proteases, alone or in combination with other enzymes, might give better yield if the reaction conditions are optimized. In contrast, extraction of dioxin and PCBs using olive oil or fish oil was very effective and resulted in 60-75% extraction of dioxin and PCBs, respectively, after a single extraction step. No preference for the oil type was observed. This method is very simple and quick and does not require an important investment for the fishmeal producer. It is expected that with optimization this method could be implemented at an industrial scale without too many difficulties. In contrast, the oxidoreductases tested did not result in a major degradation of dioxins and PCBs with only 10-15% degradation achieved. However, with the recent advancement in biotechnology, it is possible that future research will result in the development of enzymes that effectively degrade recalcitrant contaminants.