7850 research outputs found
Sort by
Acaulospora flavopapillosa, a new fungus in the Glomeromycetes from a coffee plantation in Peru, with an updated key for the identification of Acaulosporaceae species
Get PDFA new fungus of the arbuscular-mycorrhiza forming Glomeromycetes was found in a coffee plantation in Palestina, located in the Amazonian region of San Martín State in Peru. The fungus was propagated in bait cultures on Brachiaria brizantha, Medicago sativa and Sorghum vulgare as host plants. It forms typical acaulosporoid spores laterally on sporiferous saccule necks. The spores are brownish yellow to yellow brown, 125-160 μm in diam and are crowded with papillae on their surface. The papillae are approximately 1 μm wide as well as high. According to the color and surface structure of its spores, the fungus is here described under the epithet Acaulospora flavopapillosa. Phylogenetically, the new fungus clusters in a well-separated clade within a group that comprises A. fragilissima, A. saccata, A. papillosa, A. morrowiae, A. delicata, A. rugosa, A. dilatata and A. longula. Also A. excavata and A. dilatata were found by concomitant morphological and molecular phylogenetic analyses in San Martín State during this study: A. excavata in another coffee plantation, and A. dilatata in an inka nut plantation. An identification key for all species in the family Acaulosporaceae is updated in this study
Bericht vom Fachgespräch zur Rolle von Schild- und Schmierläusen als Virusvektoren im Weinbau am Oberrhein – Management und Beratungsempfehlung
Get PDFAm 07.04.2022 fand am Institut für Pflanzenschutz in Obst- und Weinbau in Siebeldingen ein Fachgespräch zur Rolle von Schild- und Schmierläusen als Virusvektoren im Weinbau am Oberrhein statt, in deme in Situationsbericht der Weinbaugebiete am Oberrhein sowie Management- und Beratungsempfehlungen erarbeitet warden sollten. Hierzu wir hier berichtet.On April 7, 2022, an expert meeting on the role of scale and mealybugs as virus vectors in viticulture in Siebeldingen in the Upper Rhine region was held at the Institute for Plant Protection in Fruit Crops and Viticulture. The aim of the meeting was to develop a situation report for the viticulture areas in the Upper Rhine region as well as management and advisory recommendations. We report on this here
Effects of temperature on pollen viability and in vivo pollen tube growth in Citrus sinensis
Get PDFTemperature is the major factor in global warming and strongly influences the success of plant sexual reproduction. Therefore, there isan urgent need to assess the vulnerability of species for breeding and planning effective actions. In this study, effects of different tempera-tures and storage duration on pollen viability and in vivo pollen tube growth were analysed in Citrus sinensis ‘Kozan yerlisi’. The pollenswere obtained before anthesis and stored at 10 °C, 20 °C and 30 °C for 1, 2 or 3 days before analysis.The pollen viability decreased with increasing temperatures and storage duration from 61.3% to 5.8%. In vivo pollen germination results showed that for one day storage, the pollen growth rates were similar to the control treatment while storing pollens two or three days differed from the control. Pollen germination after storage at 10 °C was lower and not efficient, while after storage at 30 °C no pollen tube germination at all was seen on the stigma. At the same time, storing pollen in low temperature caused delay in pollen tube germination and pollen tube growth, suggesting that pollen that are stored in low temperatures pass into a dormancy process for three to five days.In conclusion, this study indicated that pollen storage in 30 °C for a long time causes loss of pollination ability while storage in 10 °Ccauses dormancy in pollen
Relevance of RNA interference (RNAi) as a new mode of action for plant protection with high specificity
Get PDFAufgrund von verschiedenen Herausforderungen und Restriktionen sind im Bereich Pflanzenschutz neue Lösungsansätze gefordert, um zukünftigen Schädlingsproblemen zu begegnen. Eine mögliche Alternative zu konventionellen chemischen Pflanzenschutzmitteln sind Produkte, die auf dem natürlicherweise in Tieren und Pflanzen vorhandenen Kontroll- und Abwehrmechanismus der RNA-Interferenz (RNAi) beruhen. Praktische Verwendung fand RNAi bisher unter anderem bei der Erzeugung gentechnisch veränderter Pflanzen mit Virusresistenz und mit eingebautem Schutz gegen Insekten. In den letzten Jahren hat aber auch der Anwendungsbereich von extern applizierten RNA-basierten Pflanzenschutzmitteln zunehmend an Bedeutung gewonnen, und einige derartige Produkte sind schon weit in der Entwicklung. Um den sicheren und nachhaltigen Einsatz dieses neuen, durch hohe Spezifität gekennzeichneten Wirkprinzips im Pflanzenschutz zu ermöglichen, sind geeignete Regulierungsstandards und angepasste Testmethoden zur Risikoanalyse notwendig.Different challenges and restrictions require new solutions for plant protection in order to meet future pest and pathogen problems. Products based on the mechanism of RNA interference (RNAi), which is naturally present in animals and plants, offer a possible alternative to conventional chemical pesticides. Up to now, RNAi has been the basis of genetically modified plants with virus resistance and with plant incorporated protection against insects. In recent years the range of applications has been extended to externally applied RNA-based products, some of which are already quite advanced in development. In order to enable the safe and sustainable use of this new highly specific mode of action for plant protection, appropriate regulations and adapted test methods for risk analysis are required
Incidence of grapevine trunk diseases on four cultivars in Sardinia, Southern Italy
Get PDFEsca proper and Botryosphaeria dieback are among the most widespread Grapevine trunk diseases (GTDs), characterized by similar decline symptoms. In the present work, chronic, apoplexy and death symptoms were analysed separately in four vineyards and four different cultivars, on more than 1,000 vines per cultivar, taking into account ten-year annual surveys. The cumulative incidence of plants with chronic symptoms (CHR) reached high values on \u27Sauvignon Blanc\u27 (81.9 %), \u27Cabernet Sauvignon\u27 (79.4 %) and \u27Cannonau\u27 (66.5 %), but it was low on \u27Merlot\u27 (25.1 %). \u27Sauvignon Blanc\u27 showed the highest cumulative incidence of apoplectic events (23.1 %) and dead cordons (49.2 %), while \u27Cannonau\u27 had the greatest number of dead plants (28.8 %). In each symptom category, incidence among cultivars differed significantly according to χ2 test at P ≤ 0.05. Annual incidence of foliar symptoms fluctuated over ten years (ranging from 0.9-9.5 % in \u27Merlot\u27 to 6.3‑59.1 % in \u27Cabernet Sauvignon\u27), mostly with regard to CHR. On average, every year only 33.9 % of plants showing CHR had expressed symptoms in the previous year, while 48.6 % did not show symptoms the following year. Conversely, most of the plants exhibiting apoplexy or death were symptomatic the previous year. According to Tuckey HSD test (P ≤ 0.05) \u27Merlot\u27 had the highest incidence of plants showing CHR symptoms for the first time (72.1 %) and of apparently recovered plants (76.3 %), while \u27Cabernet Sauvignon\u27 exhibited the highest incidence of plants showing CHR symptoms also the previous year (50.0 %). The \u27Cabernet Sauvignon\u27 attitude to show chronic symptoms with a certain continuity was also confirmed by the low incidence of plants with hidden symptoms (lack of symptoms in previously symptomatic vines). On the contrary, the incidence of acute symptoms (apoplectic events and dead plants) was quite low on \u27Cabernet Sauvignon\u27. The present study confirms that GTD incidence is influenced by cultivar. All the cultivars assessed were susceptible, but with differences in intensity, type (chronic or acute) and fluctuation of symptoms. It cannot be excluded, however, that besides the genotype also external factors, as the vigour conferred by the type of soil or the combination with the rootstock, may have influenced the results
A \u27Regent\u27 pedigree update: ancestors, offspring and their confirmed resistance loci
Get PDF\u27Regent\u27 is the fungal resistant grapevine cultivar with the highest acreage in Germany and an important resistance donor in international breeding programs. It carries the resistance loci Rpv3.1 as well as Ren3 and Ren9 against downy and powdery mildew, respectively. As the parents of \u27Chambourcin\u27, the resistant paternal ancestor of \u27Regent\u27, did not coincide with the breeder\u27s information, the germplasm repository of JKI Geilweilerhof was screened to find the missing ancestors. SSR marker analysis revealed that \u27Joannes Seyve 11369\u27 and \u27Plantet\u27 are the true parents of \u27Chambourcin\u27 and not \u27Seyve Villard 12-417\u27 and \u27Chancellor\u27. Furthermore, the origin of the resistance loci Ren3 and Ren9 could be traced back to the genotypes \u27Seibel 4614\u27 and \u27Munson\u27. Since the breeder Hermann Jaeger mentioned \u27Munson\u27 as a direct descendant of Vitis aestivalis Michx. var. linsecomii (Buckley) L. H. Bailey and Vitis rupestris Scheele, one of these wild species might have been the donor of the loci
The influence of 1-MCP on the fruit quality and flesh browning of ‘Red Fuji’ apple after long-term cold storage
Get PDFThis study assessed the influence of 1-MCP treatment on the fruit quality and flesh browning of ‘Red Fuji’ apple at shelf life after long-term cold storage. The ‘Red Fuji’ fruit were stored at 0±0.5 °C for 270 days after treating with 1.0 μL L-1 1-methylcyclopropylene (1-MCP). Fruit quality, browning rate of stem-end flesh, chlorogenic acid content, polyphenol oxidase (PPO) activity were analyzed at shelf-life under 20±0.5 °C, the expression profile of ethylene receptors (MdERS1), phenylalnine ammonia lyase genes (MdPA L1, MdPA L2), quinate hydroxycinnamoyl/hydrxycinnamoyl CoA shi-kimate gene (MdHCT3), polyphenol oxidase genes (MdPPO1, MdPPO5)and lipoxygenase gene (MdLOX) were measured by real-time quantitative PCR.
1-MCP treatment improved the fruit storage quality, decreased stem-end flesh tissue browning, and fruit decay. In addition, the fruit respiration rate and ethylene production rate increased at shelf-life, but this increase could be inhibited by 1-MCP. The same rule was observed in the changes of chlorogenic acid content and PPO activity, the expression of MdERS1, MdPA L1, MdPPO1 and MdLOX were inhibited by 1-MCP as well in the stem-end flesh. Thus, 1-MCP treatment improves the fruit quality of ‘Red Fuji’ apple at shelf-life after long-term cold storage, and inhibits the browning of stem-end flesh by decreasing the chlorogenic acid content and PPO activity. MdPA L1, MdHCT3, MdPPO1 and MdLOX participate in the flesh browning progress
Effects of salinity on potassium absorption and expression of K+transporter genes at different concentrations of potassium in Grape (Vitis vinifera L.)
Get PDFGrapevine is classified as a moderately sensitive plant to salinity. Hydroponically three grape genotypes (Vitis vinifera L.) were treated with different concentrations of KCl (0.1, 0.3, 0.5, 1, 5, 10 mM KCl) and NaCl (0, 25, 50,100 mM NaCl). Cl- and Na+ contents were significantly increased in different plant organs of all the genotypes under salinity. In this study, sensitive (\u27GhezelUzum\u27), tolerant (\u27Gharashani\u27) and semi-resistant (\u27Chawga\u27) grape genotypes were selected based on screening experiments under salinity. \u27Gharashani\u27 accumulated higher Na+ and Cl- in roots compared to the sensitive one. \u27Chawga\u27 accumulated high K+ similar to Na+ in root and shoot even at high salinity. Km calculation for K+ and Na+ uptake in root and shoot of \u27Chawga\u27 showed that K+ and Na+ compete to enter the plant through roots. Two KUP/KT/HAK-type potassium transporters are expressed highly in the grapevine during stress. VvK1.1 could play a major role in K+ loading into grape tissues. The expression of VvKUP1 and VvKUP2 transporters and VvK1.1 channel in roots of \u27Chawga\u27 genotype increased significantly (P < 0.05) at different KCl concentrations under salinity stress. Our results showed a significant difference between tolerant and sensitive genotypes and highlighted a strong relationship between the accumulation of specific transcripts and the degree of salinity tolerance