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- Author or Editor: Richard Durham x
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Computer-aided instruction is becoming ever-more popular in higher education. The visual nature of horticultural instruction makes it particularly amenable to teaching with computer-based graphic and hypertext formats. The Texas Tech Horticulture Faculty is interested in developing multimedia materials for instruction. Thus far, attention has been directed mainly at courses in introductory horticulture and plant propagation. For the plant propagation course, one activity is the construction of a hypertext glossary in the area of asexual propagation. Topics included in the glossary include propagation by cutting, layering, budding, grafting, and micropropagation. Multiple-choice exams are also available in the module so that students can assess their understanding of the subject matter presented. The glossary is not meant to replace lecture attendance, rather students will be encouraged to access the material outside of class to supplement lecture material. The student is presented a narrative with hot-text links that when activated, pull up additional information with a combination of text and graphics. Alternatively, students can access the same information from a hierarchical topic menu. Plant propagation instructors may also benefit from the glossary's ready supply of visuals that can be down-loaded and used in a traditional classroom format.
A Community of Practice (CoP) for consumer horticulture has been formed as part of the eXtension system. The CoP was organized at the National Consumer Horticulture Forum held Nov. 2005 at the Minnesota Landscape Arboretum. The meeting was attended by representatives of 24 states from all four Extension geographical regions. The attendees discussed project priorities and began to build a framework for working together across state lines on eXtension-sponsored activities and other efforts. Initial plans from the meeting include constructing a National Consumer Horticulture FAQ database, developing online learning modules that can be used for Master Gardener training, and developing marketing tools to better identify consumer horticulture resources available through local as well as national Extension activities. This presentation will provide additional details regarding the Consumer Horticulture Forum, an update regarding consumer horticulture activities within eXtension, and an opportunity for members of ASHS to learn how they can get involved in eXtension. Information regarding eXtension CoPs (including Consumer Horticulture) is continually being updated on the eXtension CoP Web site (cop.extension.org) and information regarding the Consumer Horticulture Forum has been posted on the Consumer Horticulture CoP Community Home page (cop.extension.org/wiki/Consumer_Horticulture_Community).
Agrobacterium vitis is the causal organism of crown gall in grapevine. Infection is particularly severe in areas that experience winter damage to vines. Improving resistance to A. vitis will require a detailed knowledge about this organism. In this study, 18 grapevine isolates of A. vitis were collected from different locations near Lubbock, Texas. Isolates were subjected to a phenotypic characterization using 12 biochemical tests, including production of alkali from L-tartrate, production of 3-ketolactose, utilization of citrate, and others. Previously characterized isolates of A. vitis and A. tumefaciens obtained from the American Type Culture Collection served as positive and negative controls in these assays. Isolates were also evaluated for host range, tumor morphology, and opine utilization, and were compared at the molecular level by restriction fragment length polymorphism analysis of the oncogenic regions of the T-DNA plasmid. Although all isolates were able to metabolize tartrate and grow on Roy–Sasser media, there was much variability based on other tests. Twelve of 18 isolates were able to utilize octopine as a sole carbon source. All isolates tested thus far have been pathogenic on tomato and tests on grapevines are underway.
The Kentucy Master Gardener Program is administered through the Cooperative Extension Service of the Univ. of Kentucky with assistance from the Kentucky State Univ. Land Grant Program. Master Gardener Programs in Kentucky were originally established in urban areas of the state, but have more recently expanded to rural areas as well. Master Gardener Programs are currently active in over 25 Kentucky counties. Individual Master Gardener programs are under the direction of a county extension agent (or group of agents if the program involves multiple counties) who is assisted by two, part-time state co-coordinators (extension horticulture specialists). The county agents are responsible for Master Gardener recruitment, training, and volunteer management. A required “core content” for Master Gardener training includes a total of 24 hours of instruction in basic plant science and an orientation to Cooperative Extension. State extension specialists have compiled an extensive training manual that covers the required topics as well as additional subject areas. To become certified Master Gardeners, trainees must complete assigned homework, pass a comprehensive final exam, and complete at least one hour of volunteer service for each hour of formal instruction. The county agents determine requirements for continued certification and agents may also offer advanced Master Gardener training. This poster will provide details regarding Master Gardener recruitment, training, and retention in Kentucky.
Current propagation techniques for grapevine rootstocks involve rooting cuttings from dormant or actively growing canes and require relatively large amounts of propagation wood. We report an alternative method involving high-frequency, in vitro rooting of single-node cuttings that can be used when limited amounts of plant material are available. Propagation material was taken from greenhouse-grown plants of Vitis arizonica, V. treleasei, and V. treleasei interspecific hybrids (with V. acerifolia, V. arizonica, and/or V. doaniana) collected from the wild in New Mexico. Shoots were cut into one-node sections and surface sterilized in 25% commercial bleach for 10 minutes followed by three rinses in sterile water. The cuttings were placed on media containing half-strength Murashige and Skoog (MS) salts, MS vitamins, 20 g·L-1 sucrose, 2 g·L-1 phytagel, pH 5.8. The cuttings were incubated at 27 °C under a 16-hour photoperiod. Vitis vinifera `Cabernet Sauvignon' and `Chardonnay' were also rooted under similar conditions. All genotypes investigated rooted, but with varying frequency. Particular selections from the genotypes collected from the wild rooted at high frequency (>84% of cuttings rooted), while 66% of `Cabernet Sauvignon' and `Chardonnay' cuttings rooted. Plants were successfully established in the greenhouse. In vitro rooting of single-node cuttings appears to be a valid alternative for grapevine propagation.
GardenData.org developed from a need, identified by a survey of Kentucky county Extension agents, for a database resource to assist in answering frequently asked questions (FAQs) from home gardeners and consumers. A team, consisting of representatives from both the University of Kentucky and Kentucky State University and made up of an administrator, horticul-ture specialists, county Extension agents, and agricultural communication specialists, worked together to create GardenData.org. Development of the database of FAQs in consumer or home horticulture began in 2004 and all content is peer reviewed by Kentucky Extension specialists before making answers publicly available. An interactive prototype program was launched for use by county Extension agents in February 2005. Following a positive response Gardendata.org was made publicly available in Summer 2005. Clients are asked their electronic mail address and Kentucky county in order to enter the web site and to become a repeat user of GardenData.org. Once they have conducted a search of available FAQs, clients may submit a question to GardenData.org to be answered by Kentucky Extension personnel. From recent data (December 2005 and January 2006) the self-service rate for the site is greater than 95%, indicating that most visitors are content to search existing FAQs rather than ask a new question. As new questions are submitted, they are answered by Extension personnel, reviewed and added to the growing database of FAQs.
North American Vitis species and hybrids thereof have been the source of rootstocks for V. vinifera for the last century. Collection and evaluation of native Vitis in north-central Texas, western Texas, and New Mexico have been made to determine their current status. Known geographical pockets of grapevines were visited, with specimens taken and identified by comparison to herbarium collections and published descriptions. In locals where more than one species existed, many natural hybrids with varying morphological characteristics have become established. In North Central Texas, two areas were visited. The first was Tarrant, Parker and Wise counties where three grapevine species (V. mustangensis, V. cinerea var. helleri, and V. vulpina) and many hybrids were observed. The second was Wilbarger County where V. acerifolia was found growing in the south while V. ×doaniana was found growing in the north. West Texas was primarily populated with V. acerifolia with the exception of the Silver Falls Canyon area in Crosby County where hybrids of V. acerifolia, V. arizonica and V. riparia were observed. In New Mexico, two areas were visited: San Miquel County (North Central region), where V. acerifolia, V. arizonica, and V. riparia were observed and Eddy County (southern New Mexico) where V. arizonica was observed. A rich diversity of Vitis germplasm appears to remain in these habitats.
A high efficiency (up to 95%) shoot regeneration system for apple was developed. Explants consisted of young leaves harvested from in-vitro proliferating shoots cultures of several apple genotypes including `Dayton', `Gala', `Golden Delicious', `Malling 7a', `McIntosh', and `Royal Gala'. Leaf sections were cultured on a modified one-half strength Murashige and Skoog medium supplemented with thidiazuron (4.4 mg/L) and α-naphthaleneacetic acid (0.5 mg/L). Direct shoot organogenesis was often observed but sometimes was accompanied by callus formation. Regeneration frequency was genotype dependent. Other treatments investigated which enhanced regeneration included minced versus sectioned leaves and initial culture conditions of dark versus light. The possible applications of this regeneration system for Agrobacterium- and/or microprojectile-bombardment-mediated genetic transformation will be discussed.
DNA was extracted from leaves of various Malus genotypes and used to screen synthetic decamer oligonucleotide primers. Samples from the following two groups were bulked: 1) seven scab-susceptible apple cultivars, and 2) 15 scab-resistant apple genotypes derived by introgressive hybridization from the previous group of cultivars. A third sample consisted of DNA extracted from Malus floribunda Sieb. clone 821, the original source of apple scab resistance for all genotypes in the second group. A total of 59 primers from kits A, L, and R (Operon Technologies) were screened. Amplified fragments were obtained for 93% of the primers tested, while random amplified polymorphic DNA (RAPD) fragments were detected among samples for 76% of the primers. One primer, A15, amplified a unique band in both M. floribunda clone 821 and the bulked scab-resistant sample. This RAPD marker, designated OA15900, identifies an amplified, introgressed fragment that likely corresponds to a region of the genome that may serve as a modifier for the scab resistance gene block V, derived from M. floribunda clone 821.
Genetic linkage analysis was performed on an interspecific backcross of citrus [Citrus grandis (L.) Osbeck cv. Thong Dee X (Thong Dee X Poncirus trifoliata (L.) Raf. cv. Pomeroy)], using restriction fragment length polymorphism (RFLP) and isozyme analysis. Sixty-five progeny were analyzed for a total of 57 segregating markers including 9 isozymes and 48 RFLPs. Significant (p = 0.05) deviation from an expected 1:1 segregation ratio was observed for 21 (37%) of the 57 loci, but this did not exclude their use in the mapping study. Linkage analysis revealed that 50 loci mapped to 12 linkage groups while 7 loci segregated independently from all other markers. The total map distance included in the 12 linkage groups was 472 cM with the mean distance between markers being 12.8 cM. This does not represent a saturation of the genome with markers; however, this work demonstrates the potential for mapping traits of economic importance in citrus.