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Richard Durham

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).

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Richard Durham

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.

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Richard E. Durham*

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.

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Ashley Basinger and Richard Durham

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.

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Fokar Mohamed and Richard Durham

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.

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Richard E. Durham and Candace Harker

The Consumer Horticulture Community of Practice (CHCoP), responsible for the Gardens, Lawns, and Landscapes section of eXtension, has historically answered over 35% of the questions submitted to “Ask an Expert” (AaE)—the eXtension online, e-mail based question and answer system. Extension Master Gardener (EMG) volunteers were initially recruited to help answer questions and were responsible for resolving over 50% of the horticulture-tagged questions in 2008. With the number of questions related to horticulture nearly doubling on an annual basis, there was concern that EMGs alone would not be able to respond to all the questions. However, as eXtension has become more institutionalized in the land-grant system, county- and state-level extension staff have been encouraged to be involved in AaE. While EMG volunteers continue to play a vital role in answering questions, state extension specialists, and more so, county extension staff, are answering questions as well. This balanced approach seems more sustainable and at least 75% of questions are now being answered by an expert in the same state where the question originated.

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Richard E. Durham and Schuyler S. Korban

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.

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Richard Durham, Gloria Moore, and Charles Guy

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.

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J. Kim Pittcock and Richard E. Durham

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.