Chromatographic studies on the origin of the cultivated diploid potatosolanum × ajanhuiri juz. et buk

The leaf phenolics of the potato speciesS. × ajanhuiri, S. stenotomum, S. megistacrolobum and the artificial F₁ S. stenotomum × S. megistacrolobum hybrids have been compared using thin layer chromatography The wild potatoS. megistacrolobum produced unidentified phenolic compounds which were present in the artificialS. stenotomum × S. megistacrolobum hybrids and the YARI group ofS. × ajanhuiri, but which were absent inS. stenotomum. This further supports the hypothesis thatS. X ajanhuiri is of hybridogenic origin and was derived from natural crosses between the cultivatedS. stenotomum and the wildS. megistacrolobum.     

Inbreeding in cultivated diploid potatoes

Summary The effects of inbreeding in cultivated diploid potatoes were studied by using self-fertile hybrids from crosses between Group Phureja and Group Stenotomum and haploids of Group Tuberosum. S₁, S₂ and S₃ progenies usually exhibited decreased performance and vigour with increased inbreeding. In most families the inbreeding depression seemed to coincide with a curve claculated on the basis of the expected loss of heterozygosity in a diploid organism. The performance of some progenies deviated markedly from expectations apparently because a non-random sample of parents contributed to later generations. Many inbred genotypes were lost owing to poor seedling vigour or tuberization. This indicated the presence of many harmful recessive genes. The rapid increase in homozygosity following selfing at the diploid level provides a means for developing homozygous clones with a potential for use in future genetic investigations.

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Zusammenfassung Inzucht bei kultivierten diploiden Kartoffeln wurde m?glich, nachdem man herausgefunden hatte, dass Kreuzungen zwischen kultivierten diploiden Arten und gewissen Haploiden vonSolanum tuberosum in hohem Masse selbstfertil sind. Die ursprüngliche genetische Basis dieses Versuches bestand aus 4 Familien, die durch Kreuzungen zwischen der Gruppe Phureja und der Gruppe Stenotomum mit der Gruppe Tuberosum haploidUS-W 4 erzielt wurden. Bei einer Anzahl der untersuchten Eigneschaften stimmte die durchschnittliche Inzuchtdepression der 4 Familien mit einer Kurve überein, die auf der Basis der Heterozygotie in einem diploiden Organismus (Tabellen 1, 2 und Abb. 1) berechnet wurde. Die vier Familien reagierten unterschiedlich auf die Einkreuzung (Tabelle 1). Dies kann teilweise auf genetische Unterschiede zwischen den ursprünglichen Elternpopulationen (S₀) und auf eine Auslese auf Frohwüchsigkeit sowohl im geschlechtlichen als auch im ungeschlechtlichen Vermehrungszyklus zurückgeführt werden. Nur die kr?ftigeren Pflanzen blühten, und nur ein kleiner Teil davon war in den fortgeschrittenen Inzuchtgenerationen selbstfertil (Tabelle 4). Dies zeigt, dass Allele für Selbstunvertr?glichkeit in den Populationen noch vorhanden sind. Der niedrigere Grad der Selbstfertilit?t, ausgedrückt in Samen pro Frucht, weist beim Vergleich mit der Pollen- und der Eizellenfertilit?t darauf hin, dass rezessive lethale Gene vorhanden sind. Fortgeschrittene Inzuchtgenerationen wiesen eine abnehmende Knollenbildung auf (Tabelle 3). Beim Vergleich der Leistung der ersten Klongenerationen mit jener der ungeschlechtlichen Nachkommenschaften war die Depression in bezug auf die entsprechenden S₀'s bei den meisten Nachkommenschaften kleiner als bei ihren entsprechenden ungeschlechtlichen Elternpopulationen (Tabellen 1 und 2). Es wurden einige kr?ftige S₅-Linien erzielt, manche von ihnen besitzen einen hohen Grad von Einheitlichkeit. Die rasche Abnahme der Frohwüchsigkeit nach der Einkreuzung deutet darauf hin, dass ein Heterosiseffekt bei Kreuzung fortgeschrittener Inzuchtklone erreicht werden k?nnte. Da Inzucht durch Selbstung eine Auslese auf Selbstfertilit?t erfordert, k?nnte dieses Vorgehen einige homozygote, selbstfertile Linien hervorbringen, was für eine Untersuchung der Genetik der Selbstfertilit?t sehr nützlich w?re.

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Résumé L'autofécondation chez les pommes de terre cultivées diplo?des devint possible quand on découvrit que des croisements entre espèces cultivées diplo?des et certains haplo?des deSolanum tuberosum étaient hautement auto-fertiles. La base génétique initiale de la présente étude comprend 4 familles issues de croisements entre groupe Phureja et groupe Stenotomum avec le haplo?deUS-W4 du groupe Tuberosum. Pour un certain nombre de caractères, la dépression moyenne de consanguinité des 4 familles co?ncide avec une courbe calculée sur la base de l'hétérozygotie dans un organisme diplo?de (Tableaux 1, 2 et Fig. 1). Les 4 familles réagissaient différemment à l'autofécondation (Tableau 1). Ceci peut partiellement être attribué à des différences génétiques entre les populations parentales orignales (S₀) et à une sélection pour la vigueur dans les cycles de reproduction à la fois sexuelle et asexuelle. Seules les plantes les plus vigoureuses fleurissaient, et seule une petite partie de celles-ci étaient autofertiles dans les générations successives autofécondées (Tableau 4). Ceci indique que les allèles d'autoincompatibilité sont toujours présents dans les populations. Le niveau plus faible d'autofertilité exprimée par le nombre de graines par fruit, quand on la compare à la fertilité du pollen et de l'ovule fait supposer que des gènes létaux récessifs sont présents. Les générations autofécondées successives montrent une tubérisation décroissante (Tableau 3). Quand on compare les performances des premières générations clonales avec les descendances assexuées, la dépression, comparée aux S₀ respectifs, est plus faible chez la plupart des descendances que chez les populations parentales assexuées respectives (Tableaux 1 et 2). Plusieurs lignées S₅ bien vigoureuses ont été obtenues, plusieurs de celles-ci montrant un haut degré d'uniformité. Le déclin rapide dans la vigueur après autofécondation suggère qu'on peut obtenir des hybrides vigoureux de croisements entre clones précédemment autofécondés. Puisque la consanguinité par autofécondation impose une sélection pour l'autofertilité, on peut de la sorte produire quelques lignées homozygotes auto-fertiles qui pourraient être utiles pour une recherche sur la génétique de l'autofertilité.

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Cooperative investigations of the Crops Research Division, Agricultural Research Service, U.S. Department of Agriculture, and the Wisconsin Agricultural Experiment Station.     

The dimensions of existingSolanum germ plasma collections

Analysis of the stocks available from threeSolanum germ plasm collections (Commonwealth Potato Collection, D. D. R. Sortiment and U. S. Potato Collection) shows that an adequate number of accessions are available for only a few species. Seventy-five of the 92 wild species being maintained are representd by fewer than 20 accessions. Development of activeSolanum germ plasm collections in the centers of diversity for these species eventually may provide the broader base of germ plasm needed for potato research.     

Differentiation of gastrointestinal diseases of calves.

With a complete history, careful physical examination, and targeted diagnostics, the practitioner can differentiate the causes of gastrointestinal diseases in calves. The authors hope that this article helps the practitioner in this regard. Armed with a diagnosis, he or she can then proceed with proper treatment and prevention, which is the ultimate goal.     

A dielectric omnidirectional reflector

A design criterion that permits truly omnidirectional reflectivity for all polarizations of incident light over a wide selectable range of frequencies was used in fabricating an all-dielectric omnidirectional reflector consisting of multilayer films. The reflector was simply constructed as a stack of nine alternating micrometer-thick layers of polystyrene and tellurium and demonstrates omnidirectional reflection over the wavelength range from 10 to 15 micrometers. Because the omnidirectionality criterion is general, it can be used to design omnidirectional reflectors in many frequency ranges of interest. Potential uses depend on the geometry of the system. For example, coating of an enclosure will result in an optical cavity. A hollow tube will produce a low-loss, broadband waveguide, whereas a planar film could be used as an efficient radiative heat barrier or collector in thermoelectric devices.     

Evaluation of the oral vitamin E absorption test in horses

An oral vitamin E absorption test used in human beings was modified for use in horses. The most appropriate techniques with which to measure gastrointestinal tract absorption of vitamin E (alpha-tocopherol) in horses were developed. Vitamin E was administered orally, and serum values of alpha-tocopherol were measured by use of high-performance liquid chromatography at 0, 3, 6, 9, 12, and 24 hours after vitamin E administration. Variables included comparison of 2 dosages (45 and 90 IU/kg of body weight), routes of administration, and absorption dynamics of 3 preparations of dl-alpha-tocopherol. Absorption of the 2 doses of dl-alpha-tocopherol acetate indicated a dose response; the area under the curve at 24 hours (AUC24) was 4.3 micrograms.h/ml for the 45-IU/kg dose and 32.2 micrograms.h/ml (P less than 0.01) for the 90-IU/kg dose. Maximal absorption was apparent when vitamin E was naturally consumed in grain, compared with administration of identical preparations by stomach tube or paste. In the same horses, dl-alpha-tocopherol and dl-alpha-tocopherol acetate plus polyethylene glycol had statistically similar absorption curves and both had significantly greater AUC24, compared with dl-alpha-tocopherol acetate; values for the 3 compounds were 23.6, 25.8, and 12.6 micrograms.h/ml, respectively. The AUC24 varied between individual horses, but time of peak value was consistently observed between 6 and 9 hours.(ABSTRACT TRUNCATED AT 250 WORDS)     

A framework for evaluation of on-farm mastitis diagnostics in Australia

Numerous culture-based diagnostics are available on the Australian and international markets for on-farm detection of bacterial pathogens in milk. Use of such diagnostics may provide an opportunity to improve the prudent use of antimicrobials in udder health management. Farms are low-resource settings in terms of diagnostic microbiology capacity. The World Health Organisation has identified criteria for the evaluation of diagnostic tests in low resource settings based on Accuracy, Sensitivity, Specificity, User-friendliness, being Rapid or Robust, Equipment-free and being Deliverable (ASSURED). Here, we review how those criteria can be interpreted in the context of microbiological diagnosis of mastitis pathogens, and how on-farm diagnostics that are currently available in Australia perform relative to ASSURED criteria. This evaluation identifies multiple trade-offs, both with regard to scientific criteria and with regards to convenience criteria. More importantly, the purpose of testing may differ between farms, and test performance should be evaluated relative to its intended use. The ability of on-farm mastitis diagnostics to inform mastitis treatment decision-making in a timely and cost-effective manner depends not just on test characteristics but also on farm-specific pathogen prevalence, and on the farm enterprise's priorities and the farm manager's potential courses of action. With most assay evaluations to date conducted in professional laboratories, there is a surprising dearth of information on how well any of the diagnostic tests perform on-farm and, indeed, of the on-farm decision-making processes that they aim to inform.