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  • Author or Editor: Tim D. Davis x
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Lupinus havardii (Big Bend bluebonnet) is native to a narrow geographical range along the Rio Grande River in southwest Texas and produces attractive blue flower spikes which have potential as cut flowers. Without any post-harvest treatments, these spikes had an average vaselife in water of about 7 d. During this period, an average of about 13 florets were abscised per spike. When preconditioned for 4 h in 40-80 mg/liter silver thiosulfate (STS), vaselife increased to 11 days and only 1-3 florets were abscised per spike. Post-harvest treatment of the spikes with 25-50 mg/liter oxime ether, a new ethylene inhibitor, surprisingly enhanced floret abscission and shortened vaselife. The basis for this response is not clear. Storage of STS-preconditioned spikes in water at 5C for 72 h only decreased vaselife by about one day compared to unstored controls. Dry post-harvest storage at 5C for 72 h caused severe wilting, but upon rehydration these spikes still had a vase/life of about 8 d. These results indicate mat cut flower spikes of L. havardii have good post-harvest qualities and can be stored for up to 3d without seriously limiting vaselife.

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Surveys were sent to 53 North American universities offering horticulture curricula to characterize the types of degrees offered, student demographics, participation in distance education, remuneration and assistance available for graduate students, and faculty rank and salary distributions. Twenty-five institutions responded. This represented 10 PhD, 14 MS, and 12 M. Agr. or MS non-thesis professional degree programs in horticulture and 13 PhD, 13 MS, 12 M. Agr. or M. non-thesis degree programs in plant sciences or a closely related area. On average, graduate students were predominantly Caucasian (70.7%), followed by Asian (16.1%), Black (3.2%), Hispanic (2.6%), and Native American (0.2%). Most were supported by research assistantships (56.3%), with the second largest group being self-supported (13.8%). Teaching assistantships were a small source of support (4.6%). Stipends (12-month equivalent) where variable among fellowships ($2000 to $30,000), teaching ($6600 to $25,000), research ($2000 to $25,239), extension ($12,000 to $17,000), or combination assistantships ($900 to $26,000). Most assistantships included a stipend plus in-state and out-of-state tuition waivers: about half included medical insurance. Mean full-time in-state tuition and fees was $6,535, while out-of-state was $13,876. Participation in distance courses was greatest for non-degree students (18.3%), and low for all others (9.2% to 6.4%). The average academic unit had 15.1 professors, 8.9 associate professors, 6.8 assistant professors, 0.3 senior lecturers, and 1.6 lecturers with mean reported average salaries of $85,142; $70,132; $58,918; $55,608; and $37,887, respectively.

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Seeds of Lupinus havardii Wats. (Big Bend bluebonnet), a potential cut flower crop, were subjected to a variety of scarification and temperature treatments. Without scarification, only 10-20% of the seeds germinated within one week. Germination percentages increased sigmoidally as scarification time in concentrated sulfuric acid increased. Nearly 100% germination was obtained within one week after seeds were placed in sulfuric acid for 120 min. Nicking the seed coat with a razor blade also resulted in near 100% germination. Soaking the seed in water for 24 h failed to enhance germination. Soaking the seed in ethanol, methanol, or acetone for 2 h likewise failed to enhance germination. Total germination of scarified seed was >90% between 21 and 33C within 28 h. The most rapid germination occurred within a range of 24-29C. Above or below this range germination was delayed. At 35C, seedling, mortality was observed and total germination was reduced to <50%. Our data indicate that seed of this species requires scarification for optimum germination but the seed can germinate over a relatively wide temperature range.

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The Republic of the Union of Myanmar (also known as Burma) has been undergoing political transformation in recent years that has opened up new opportunities for agricultural development. Agriculture is an important component of the country’s economy, and horticultural production has good potential for fostering development. Compared with many other developing countries, Myanmar is relatively rich in natural resources (e.g., water) that could support diverse horticultural crop production. Precipitation is relatively abundant but seasonable, and much of the country is frost free. Nonetheless, for the vast majority of fruit and vegetable crops, yields are well below world averages. The agriculture sector contributes 38% of the country’s gross domestic product (GDP) and employs more than 60% of the workforce. However, Myanmar has only one agricultural university, and the supply of well-qualified graduates is far below that which is needed for a robust horticultural sector. Horticulture is one of the major departments at the agricultural university. Many faculty and students are enthusiastic, motivated, and open to professional development. Hence, there is a significant opportunity to increase academic and technical capacity in horticulture. Specific areas of need include seed science technology, improved fertilizer use, pest management practices, postharvest technology, improved genetic resources, application of biotechnology, and increased extension advisory services. Although there are many obstacles to overcome, improved and sustainable horticultural crop production provides a significant opportunity for addressing human nutrition and economic development issues in the country.

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Abstract

Successful in vitro propagation of white rubber rabbitbrush [Chrysothamnus nauseosus (Pallas) Britt, ssp. albicaulis] was achieved using both stem segments and axillary shoot explants. Medium stem segments (2–3 mm diameter) were more successfully cultured than either small (0.8–1 mm diameter) or large (4–5 mm diameter) explants. Axillary shoot explants (10–15 mm long) began to form roots within 1 week after placement in media containing 5–10 μM (1–2 mg/liter) indolebutyric acid (IBA) or 5.3–10.6 μM (1–2 mg/liter) naphthalene-acetic acid (NAA). Root growth was accelerated in the presence of IBA. In the presence of 8.9 μM (2 mg/liter) benzyladenine (BA) and 0.53μM (0.1 mg/liter) NAA, both medium stem segments and axillary shoots rapidly produced numerous side shoots that were rooted easily on media containing IBA. In vitro culture appears to be a feasible means for the mass multiplication of this potentially important rubber-producing shrub.

Open Access

A comprehensive survey of American and Canadian universities that offer masters, doctoral, or both degrees in horticulture resulted in responses from 27 academic units. Units were surveyed regarding types of degrees offered, admissions policies, demographic characteristics of students, financial assistance provided to students, faculty ranks and salaries, and metrics by which the programs were evaluated by university administration. About 80% of the programs resided in 1862 Morrill Act land-grant institutions (LG) with the remainder housed in other non-land-grant institutions (NLG). Thirty-eight percent of reporting LG programs existed as stand-alone horticulture departments, whereas horticulture programs were combined with other disciplines in the remainder. Admissions criteria were most consistent among LG programs. Participation in distance education programs was low, but growing. Financial support of graduate students was more common in LG programs. Most schools offered some sort of tuition reduction to those students on assistantships/fellowships and offered health insurance options. Payment of fees was rare and the level of stipends provided varied substantially among programs. International student enrollment was greatest at LG programs and had remained steady in recent years. Gender equity was present among graduate students, with nearly equal male and female enrollment. Most graduate students at both LG (63.6%) and NLG (75.0%) programs were non-Hispanic White; although overall minority enrollment had increased but was still not similar in distribution to that of the general U.S. population. Professors (46.7%) and Associate Professors (28.3%) dominated the faculty ranks while Assistant Professors (19.3%) and lecturers/instructors (5.7%) constituted a much smaller portion of the faculty. Faculty salaries varied tremendously among institutions, especially for senior faculty. Female and ethnic minorities were underrepresented in faculty ranks compared with the general U.S. population. Aside from total graduate program enrollment, the relative importance of various evaluation metrics for programs was highly variable among institutions. Data discussed herein should be useful to universities with horticulture graduate programs for peer institution comparisons during program assessments, accreditation reviews, or for strategic planning purposes.

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Abstract

Severely chlorotic ‘Red Delicious’ apple (Malus domestica Borkh.) trees growing on a calcareous soil were treated for iron (Fe) chlorosis with pressure injections of 1.0% (w:w) solutions of ferrous sulfate, ferric citrate, or Fe-Sequestrene-330 (Fe-330). Injections were made in September of 1981 and in April, June, and July of 1983. All treatments increased chlorophyll concentrations compared to controls, and treatments made in September of 1981 and in April and June of 1983 increased shoot growth during the 1983 growing season compared to controls. Although the treatments did result in a temporary increase in foliar Fe content, there was not a strong correlation between foliar Fe and chlorophyll concentration. Ferrous sulfate and Fe-330 were more effective than ferric citrate in alleviating chlorosis. Injections made in April and June of 1983 greatly increased bloom in May of 1984, compared to trees injected in July of 1983 and the untreated controls. Hence, injections should be made early in the season (before July) in order to promote bloom the following growing season.

Open Access

Abstract

Severely chlorotic ‘Delicious’ apple (Malus domestica Borkh.) trees growing in a calcareous soil were pressure-injected with a 1.0% (w/w) ferrous sulfate solution. Net photosynthesis (Pn) of iron-treated trees was at least 50% greater than controls within 10 days after injection and reached as high as 115% above controls during the first growing season. Chlorophyll (Chl) concentration closely paralleled Pn during the first growing season, but the correlation was not as strong thereafter. During the 3rd growing season after injection, Pn of injected trees declined, yet still remained greater than controls until September (last sampling date). Visual chlorosis reappeared in the young terminal leaves near the end of the 3rd growing season. Stomatal diffusive resistance was unaffected by the treatments. Foliar iron concentrations in treated trees increased above the controls for about 2 months after injection. Thereafter, foliar iron content gradually decreased until the end of the first growing season, after which concentrations were similar to controls. Results indicate that injection of iron into chlorotic apple trees can enhance Pn and Chl for at least 3 growing seasons.

Open Access

Abstract

Cucumber (Cucumis sativus L. cv. Marketer) seedlings were treated with 100 μg of soil-applied uniconazole and then exposed to 22 or − 1C for 8 hours 1 week following treatment. Following exposure to − 1C, electrolyte leakage from leaf tissue of treated plants was about one-third that of the controls, indicating that uniconazole reduced low-temperature damage. Foliar proline content was unaffected by uniconazole at 22C, but, following low temperature exposure, was ≈25% less in treated than in control plants. Following low-temperature exposure, malondialdehyde content was ≈25% less in treated seedlings than in controls, suggesting that uniconazole may have decreased low temperature-induced lipid peroxidation. Uniconazole-induced low-temperature tolerance was accompanied by increased levels or activities of various antioxidants, including glutathione, peroxidase, and catalase. These results are consistent with the hypothesis that triazole-induced stress tolerance is due, at least in part, to increased antioxidant activity that reduces stress-related oxidative damage to cell membranes. Chemical names used: γ-L-glutamyl-L-cysteinyl-glycine (glutathione); (E)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)penten-3-ol (uniconazole, XE-1019).

Open Access