Formation of canker lesions on stems and black scurf on tubers in experimentally inoculated potato plants by isolates of AG2-1, AG3 and AG5 of Rhizoctonia solani: a pilot study and literature review

Development of black scurf on potato tubers (cv. Nicola) was compared in plants inoculated with isolates of Rhizoctonia solani of three anastomosis groups (AG2-1, AG3 and AG5) which occur in potato crops in Finland. All isolates induced stem canker lesions but only isolates of AG3 formed efficiently black scurf on progeny tubers. Among the AG2-1 and AG5 isolates tested, only one AG2-1 isolate formed a few sclerotia on 13.5 % of the progeny tubers in one experiment. The data indicate that isolates of AG3 differ from those of AG2-1 and AG5 in having a higher ability to form sclerotia on tubers. Therefore, while AG2-1 and AG5 isolates have a broader host range, AG3 is more efficient in producing black scurf, which provides this anastomosis group with more efficient means of dissemination on seed potatoes. These differences probably explain the predominance of AG3 (98.9 % of isolates) in potato crops in Finland and other northern potato production areas

Complete genome sequence of Salmonella enterica serovar Typhimurium U288

Salmonella enterica serovar Typhimurium U288 has firmly established itself within the United Kingdom pig production industry. The prevalence of this highly pathogenic multidrug-resistant serovar at such a critical point in the food chain is therefore of great concern. To enhance our understanding of this microorganism, whole-genome and plasmid sequencing was performed

Viljelymenetelmän, lajikkeen ja siemenperunan seittirupisuuden vaikutus perunaseitin (Rhizoctonia solani) määrään

Siemenen seittirupisuuden (6 tasoa), maaperän ominaisuuksien (monokulttuuri tai luomuviljely) ja lajikkeen (Van Gogh tai Saturna) vaikutusta perunaseitin esiintymiseen tutkittiin vuosina 2003-2005 järjestetyssä kenttäkokeessa. Siemenperunan tautisuuden (seittirupisuuden) lisääntyessä versolaikun määrä kasvoi, varsi- ja mukulaluku pieneni ja sadon määrää ja tärkkelyspitoisuus laski. Myöskin laatu heikkeni, kun vihertyneiden, epämuotoisten ja onttojen mukuloiden osuus sadossa kasvoi. Viljelymenetelmä ei vaikuttanut kovin selvästi seittisyyteen, mutta siemenen seittirupisuuden lisääntyessä seittiruven määrä sadossa lisääntyi ainoastaan luomussa. Van Goghissa oli seittiongelmia hieman enemmän kuin Saturnassa. Erityisesti keskeltä ruskolaikkuisten ja onttojen mukuloiden määrä lisääntyi Van Goghilla selvästi siemenen seittirupisuuden lisääntyessä. Tulokset ovat alustavia ja kattavat kaksi ensimmäistä koevuotta (2003-2004)

Isotopic and spin selectivity of H_2 adsorbed in bundles of carbon nanotubes

Due to its large surface area and strongly attractive potential, a bundle of carbon nanotubes is an ideal substrate material for gas storage. In addition, adsorption in nanotubes can be exploited in order to separate the components of a mixture. In this paper, we investigate the preferential adsorption of D_2 versus H_2(isotope selectivity) and of ortho versus para(spin selectivity) molecules confined in the one-dimensional grooves and interstitial channels of carbon nanotube bundles. We perform selectivity calculations in the low coverage regime, neglecting interactions between adsorbate molecules. We find substantial spin selectivity for a range of temperatures up to 100 K, and even greater isotope selectivity for an extended range of temperatures,up to 300 K. This isotope selectivity is consistent with recent experimental data, which exhibit a large difference between the isosteric heats of D_2 and H_2 adsorbed in these bundles.Comment: Paper submitted to Phys.Rev. B; 17 pages, 2 tables, 6 figure