Browsing by Author "Pattison, Jeremy A."

Now showing 1 - 5 of 5
  • Thumbnail Image
    Frost/Freeze Protection in Strawberries
    Pattison, Jeremy A. (Virginia Cooperative Extension, 2009)
    Discusses ways to protect strawberry plants, blossoms and fruits from damage by frost and freeze conditions.
  • Thumbnail Image
    Improved regeneration and Agrobacterium-mediated transformation of wild strawberry (Fragaria vesca L.)
    Wadl, Phillip A. (Virginia Tech, 2005-12-14)
    The Rosaceae contains many important commercially grown fruit crops. No comprehensive genomics platform is currently under development for fruit crops, giving functional genomics studies with wild strawberry (Fragaria vesca L.) the potential of identifying genes important in fruit crops. Fragaria vesca has a small genome size compared to the cultivated strawberry, Fragaria à ananassa Duch. (164 vs. 600 Mbp per 1C nucleus). This feature, in addition to a short life cycle (12-16 weeks) and small plant size make F. vesca a good candidate for a model plant for genetic and molecular studies. The specific objective of this work was to develop an efficient high-throughput Agrobacterium-mediated transformation protocol to generate an insertional mutant population to support the justification of F. vesca as a model organism for rosaceous crops. The transformation techniques described by Alsheikh et al. (2002) and Oosumi et al. (2005) were modified and applied to a range of germplasm obtained from the USDA National Germplasm Repository. We found that the modifications made to the Alsheikh protocol were unsuccessful when applied to our germplasm. With the Oosumi et al. (2005) protocol, transformation efficiencies ranging from 11 to 100% were obtained for two accessions when explants were exposed to varying durations on TDZ containing medium during shoot regeneration. The transformation efficiency was given as the mean number of GFP+ plants obtained per primary explant cultured. Multiplex PCR, for amplification of the hptII and GFP genes, was performed on a random sample of GFP+ plants to verify insertion of the T-DNA. The statistical power of our experiment was insufficient to detect treatment effect but based on our findings the transformation efficiencies were high enough to justify PI 551572 for use in the high throughput transformations that are required to generate a population of insertional mutants large enough for gene discovery in F. vesca.
  • Thumbnail Image
    Induced disease resistance elicited by acibenzolar-S-methyl and plant growth-promoting rhizobacteria in tobacco (Nicotiana tabacum L.)
    Parkunan, Venkatesan (Virginia Tech, 2008-09-15)
    Active disease resistance in plants is induced during the pathogen infection process that triggers multiple defense-related genes to establish broad-spectrum resistance. Several biotic and abiotic agents can mimic natural induced resistance (IR), categorized as systemic acquired (SAR) or induced systemic resistance (ISR). IR, triggered by acibenzolar-S-methyl (ASM) or plant growth-promoting rhizobacteria (PGPR), was evaluated on two-to-three types of tobacco in greenhouse and field studies. Tobacco mosaic virus (TMV) local lesion assays monitored induction and maintenance of ASM-induced SAR over a 21 day period via proportional reduction in the number of TMV local lesions between an untreated control and ASM-treated plants. Intraspecific variation in SAR was found among tobacco types; burley and flue-cured tobaccos responded by day 3, while oriental tobacco responded between day 3 and 6. The SAR signal was greatest between 6 and 15 days following ASM application, but IR was slightly evident even at 21 days after ASM application in all three tobacco types. Bottom and middle leaves responded similarly on all sample dates, but top leaves showed the weakest SAR response. Tobacco cyst nematode (TCN; Globodera tabacum solanacearum) is one of the most destructive pathogens of tobacco in Virginia. Among four PGPR combinations tested, a mixture of Bacillus amyloliquefaciens IN937a (GB99) and B. subtilis A13 (GB122) most consistently suppressed TCN reproduction in flue-cured and oriental tobacco. Application of ASM similarly reduced final numbers of TCN cysts, but also resulted in chlorosis, stunting, and lower plant fresh weight. GB99+GB122 also suppressed TCN development and reproduction in susceptible and resistant flue-cured cultivars, but reductions by ASM were less consistent. In a split-root trial, soil amendment with GB99+GB122 in one half of an oriental tobacco root system lowered final numbers of TCN more than did ASM. ASM exhibited undesirable effects in phytotoxicity trials in flue-cured and oriental tobacco, but GB99+GB122 was not phytotoxic. When oriental tobacco seedlings were grown in a GB99+GB122-treated soil-less media, a single application of 200 mg ASM/L one week after transplanting significantly suppressed TCN reproduction in the field without phytotoxicity. Further field research is needed to confirm this effect in flue-cured tobacco.
  • Thumbnail Image
    Pest Management of Japanese Beetle (Coleoptera: Scarabaeidae) and a Study of Stink Bug (Hemiptera: Pentatomidae) Injury on Primocane-bearing Caneberries in Southwest Virginia
    Maxey, Laura Michele (Virginia Tech, 2011-02-17)
    Field experiments (2007-2009) and laboratory bioassays (2009) tested the efficacy of insecticides with short pre-harvest intervals, caneberry cultivar susceptibility, and geranium toxicity for reducing Japanese beetle (JB) activity on primocane-bearing caneberries. Deltamethrin, chlorantraniliprole, bifenthrin, lime-alum, and thyme oil reduced JB activity in the field. Deltamethrin, chlorantraniliprole, acetamiprid, an azadirachtin and pyrethrin mixture, an azadirachtin and neem oil extract mixture, and an extract of Chenopodium ambrosioides reduced JB activity during the bioassays. "Prelude" had significantly more JB than "Anne", "Caroline", "Heritage", "Dinkum", or "Himbo Top" and "Prime-Jan" had significantly more JB than "Prime-Jim". Compared to certain cultivars, "Heritage", "Caroline", "Himbo Top", and "Prime-Jan" had higher percentages of injured fruit and "Autumn Bliss", "Heritage", and "Caroline" produced greater marketable and overall yields. "Prime-Jan" produced more overall yield than "Prime-Jim"; marketable yields from both blackberry cultivars were similar. Defoliation was significantly less for "Dinkum", "Caroline", "Heritage", and "Anne" than for "Prelude" in 2008 and significantly less for "Caroline" and "Anne" than "Prelude" or "Fall Gold" in 2009. In field tests, previous consumption of geraniums lessened raspberry defoliation by JB. Bioassays indicated that JB activity was only reduced if JB were continually exposed to geranium. Therefore, the efficacy of geranium as a trap crop for JB may be limited. The stink bug species within the caneberries were identified (2008-2009) and Euschistus servus (Say) made up 48.1 % of the overall species composition. Stink bug injury to ripening raspberries was identified as small holes between drupelets; stink bug excretions also ruined fruit.
  • Thumbnail Image
    Specialty Crop Profile: Blueberries
    Bratsch, Tony; Pattison, Jeremy A. (Virginia Cooperative Extension, 2009)
    Discusses blueberries as a marketable specialty crop, and offers advice about species and cultivar selection, choice of site, and site preparation, harvesting and handling, and marketing.