Hydrology influences breeding time in the white-throated dipper

While nitrogen and carbon stable isotope values can reflect ecological segregation, prey choice and spatial distribution in seabirds, the interpretation of bulk stable isotope values is frequently hampered by a lack of isotopic baseline data. In this study, we used compound-specific isotope analyses of amino acids (CSIA-AA) to overcome this constraint and to study interspecific differences, seasonal and historical changes in trophic positions of five seabird species, three penguins and two petrels, from a sub-Antarctic seabird community. CSIA-AA allowed comparing trophic positions of seabirds with temperate and polar distributions. Gentoo and Magellanic penguins had the highest trophic positions during the breeding season (3.7 and 3.9), but decreased these (2.9 and 3.3) during the feed-up for moult. Intra-specific differences were also detected in Thin-billed prions, where carbon isotope values clearly separated individuals with polar and temperate distributions, both in the breeding and interbreeding periods. Thin-billed prions that foraged in polar waters had lower trophic positions (3.2) than conspecifics foraging in temperate waters (3.8). We further investigated historical changes by comparing museum samples with samples collected recently. Our pilot study suggests that Rockhopper penguins, Magellanic penguins and Thin-billed prions with temperate non-breeding distributions had retained their trophic levels over a 90–100 year period, while Gentoo penguins and Thin-billed prions with polar non-breeding distributions had decreased trophic levels compared to historical samples. In contrast, Wilson’s storm-petrels had slightly increased trophic levels compared to samples taken in 1924–1930. We applied compound-specific stable isotope analyses across a range of contexts, from intra-specific comparisons between stages of the breeding cycle to inter-specific seabird community analysis that would not have been possible using bulk stable isotope analyses alone due to differences in isotopic baselines.     

QTL analysis of resistance to powdery mildew in hop (<Emphasis Type="Italic">Humulus lupulus</Emphasis> L.)

Hop with powdery mildew [HPM: caused by Podosphaera macularis (Wallr.) U. Braun & S. Takam.] results in significant losses in hop production by reducing yield and quality. One means of increasing yield and quality is the production of resistant hop lines. Breeding for resistance can be significantly improved and accelerated by use of marker-assisted selection. The objective of this preliminary study was to identify QTLs and markers for genetic resistance to HPM. A bi-parental mapping population between the resistant line “Newport” and susceptible line ‘21110M’. Phenotypic data was scored under controlled greenhouse conditions. Significant differences among offspring were observed and disease resistance did not follow a distinct binomial distribution, suggesting quantitative genetic control. Genotyping-by-sequencing resulted in approximately 375 K SNP markers, which were filtered down to 2263 markers mapped to 10 linkage groups. Interval Mapping identified four QTLs with one on linkage group 1 and three located on linkage group 6. Composite interval mapping identified three QTLs, all located on linkage group 6. Mixed linear models identified 15 markers associated with expression of resistance to HPM. Three of these 15 SNPs were also identified in QTL-CIM analysis. Evaluation of the scaffolds containing the significant SNP markers identified seven putative genes—several of which appear involved in disease resistance in other plant species. The SNP markers identified in this study still require validation in unrelated populations prior to implementation in breeding programs.     

Die Bestimmung der Tiefgefriertauglichkeit von Bullensperma mit Hilfe des Objektträgertestes

Inhalt Es Wurde versucht, 276 Ejakulate von 50 Bullen der Rasse Deutsche. Fleckvich mit Hilfe eines einfachen Objekträgertestes ohne die im Ruutineverfahren üblichen Maβnahmen (Adaption, Einfrieren) auf ihre Gefriertauglichkeit zu testen. Dies erfolgte durch einen Vergleich der Auftauraten von verdünnten Spermaproben gleich nach dem Tiefgefrieren ohne Adaption auf Objektträgern und von solchen die nach 6–8stündigcr Adaption routinemäβig in Ampullen bzw. Pailletten eingefroren wurden. Die Untersuchungen führten zu folgenden Ergebnissen: 1. Die Auftaurate von Spermaproben, die ohne Adaption auf Objektträgern im Stickstoffdampf eingefroren wurden, lassen bis zu einem gewissen Grade eine Vorausbestimmung des Einfrierergebnisses und damit der Tiefgefriertauglichkeit eines Ejakulates zu. Bullen, deren Sperma im Objektträgertest ein Auftaurate von über 20% zeigt, werden als gefriertauglich, jene mit einer Spermienmotilität nach dem Auftauen der Objektträgerproben von unter 5% als gefrieruntauglich und solche, deren aufgetautes Sperma 5% bis 20 % motile Spermien aufweisen, als bedingt tauglich angesprochen. 2. Zur Beurteilung eines Bullen hinsichtliclz der Gefriertauglichkeit seines Spermas reicht die Testung von 3 Ejakulaten aus. 3. Der Objektträgertest ist leicht durchführbar und zeitsparend. Er ist für die Auswahl der Bullen hinsichtlich der Gefriertauglichkeit ihres Spermas für die Praxis allerdings nur bedingt einsatzfähig, da ein groβer Teil der Stiere doch noch routinemäβig nachgetestet werden muβ. Er bringt eindeutige Ergebnisse nur dann, wenn die Auftaurate höchstens 5% und deutlich mehr als 20 % beträgt. Contents (The determination of the suitability for deep freezing of bull semen using a slide test) . 276 ejaculates from 50 bulls of ther German Fleckvieh breed were studied for deep freezing suitability using a simple slide test without the routinely used mea.rures (adaptation, freezing). A comparison was made of the thawing rates of diluted semen samples immediately after deep-freezing without adaptation on slides and after 6–8 hours adaptntion in ampoules or paillettes. The following results were obtained: 1. The thawing rate of semen samples frozen without adaptation on slides in the vapour phase of nitrogen allow a certain degree of predetermination of the freezing result and therefore of the suitability of an ejaculate for deep freezing. Bulls whose semen shows a thawing rate of over 20% by the slide test are taken as being suitable for freezing; those with a sperm motility after the slide test of less than 5% are unsuitable; those with a sperm motility of 5–20% are considered as conditionally suitable. 2. 3 ejaculates are sufficient to test a bull for suitability of semen for deep-freezing. 3. The slide test is easy to carry out and saves time. However, for the selection of bulls on the basis of deep freezing of semen in practice it is limited, since a large proportion of bulls still have to be tested further. The test only gives unequivocal results if the thawing rate is less than 5% or more than 20%.     

Ein Beitrag zur Beurteilung der täglichen Spermienproduktion bei Ebern der Deutschen Landrasse

Inhalt Bei 8 Ebern der Deutschen Landrasse im Alter von 1 bis 4 Jahren wurde die spermatogenetische Leistung durch Entsamungen mit unterschiedlichen Intervallen untersucht. Dabei wurde festgestellt, daβ die tägliche Spermienproduktion des 1jährigen Ebers bei 10 · 10⁹ Spermien liegt und beim 4jährigen Eber 20 · 10⁹übersteigt. Die Spermienproduktion von Ebern ist, wie bei anderen Tierarten, von Alter und damit vom steigenden Hodengewicht der Tiere abhängig. Mit einer Vergröβerung der Entsamungspausen steigen die Spermienverluste an und der errechnete tägliche Spermien-“output” nimmt ab. Contents (A contribution to the evaluation of the daily sperm production of boars of German Landrace breed). The “Daily Sperm Output” in boars was examined by means of various semen collection intervals. Eight boars–German landrace type, age one to four years-served as test animals. The investigations established a daily sperm production of 10·10⁹ sperms with one year old boars whereas 4 years old boars produce more than 20 · 10⁹ sperms. The sperm production depends on age and growing testis weight as is observed in other animal species With increased pauses of semen collection sperm losses are likewise increased, and the calculated “Daily Sperm Output” is diminished.     

Untersuchungen uber den Einfluß von Prolan A1) und Norethisteronazetat2) auf die Spermaqualität von Ziegenböcken

Inhalt: Die Ejakulate von 10 Ziegenböcken wurden dahingehend geprüft, ob und in welcher Weise durch die Zufuhr von Prolan A (parenteral) bzw. Norethisteronazetat (peroral) die Samenbeschaffenheit verändert wird. Die Auswertung der Versuchsergebnisse erfolgte auf rechnerischem Wege und an Hand graphischer Darstellungen. Contents: The effect of parenteral application of Prolan A and of oral application of Norethisteronacetate, on quality of sperma, were tested on 10 male goats. Results were evaluated both statistially and graphically.