Over the years, by recurrent phenotypic selection, breeding and evaluation, we have developed blue, white, and pink flowered lines of Big Bend bluebonnet (L. havardii Wats.). The racemes, which differ in their sensitivity to ethylene, hold promise as a new specialty cut flower crop. The key determinants of postharvest longevity and performance of cut racemes are flower abscission and senescence. Our studies indicated that the addition of sucrose in the holding solution greatly enhanced the vase life, although the optimum sucrose concentration varied considerably in different lines. In blue flowered lines (e.g., `Texas Sapphire', Blue Select) sucrose concentration greater than 2% induced `osmotic wilting' followed by senescence of the standard petal (banner spot petal), while the petals in white flowered lines (e.g., `Texas Ice', White Select) did not show any wilting even in 4% to 6% sucrose. Ethylene perception inhibitors such as 1-MCP or STS completely suppressed the induction of flower abscission in racemes of all the bluebonnet lines. Ethylene biosynthesis inhibitors (e.g., ReTain, CO++), on the other hand, were relatively less effective than 1-MCP/STS. Both ethylene perception as well as biosynthesis inhibitors, in combination with sucrose, acted additively and further enhanced the postharvest performance by delaying flower abscission/senescence.
Wayne Mackay*, Narendra Sankhla, and Tim Davis
Wayne A. Mackay and Tim D. Davis
The Big Bend bluebonnet, Lupinus havardii Wats., is a showy winter annual native to a narrow geographical range in southwestern Texas with blue, fragrant 0.5–1.0-m-long racemes. The L. havardii raceme has considerable potential in the floral industry, because there is a need for high-quality, durable, raceme-type cut flowers. We began a research and breeding project in 1991 aimed at evaluating the potential for this species as a specialty cut flower. Breeding strategies included the development of selfed populations as well as random pollinations among selected individuals with the aim of improving flower color, uniformity, yield, and postharvest performance. Recurrent phenotypic selection has resulted in the development of blue, pink, and white color lines. Concurrently with the breeding efforts, research on seed germination, greenhouse culture for year-round production, postharvest handling, and shipping requirements have been conducted. Trials have indicated that L. havardii is adaptable to greenhouse culture and that individual plants can produce 15–25 marketable racemes within 4–5 months from sowing. Two years of commercial greenhouse trials have been completed. Blue and white cultivars will be released by Texas A&M Univ. within the next year.
Tim D. Davis, James E. Ells, and Ronald H. Walser
Seeds of Lycopersicon esculentum Mill. cv. UC 82L were treated with hypertonic priming solutions containing KNO3 and K3PO4(10 g·liter-1 each), and various concentrations of uniconazole before sowing. Treatment of the seed with priming solution only hastened emergence by ≈ 2 days compared to untreated seed sown directly from the packet, but did not affect total emergence after 12 days. Addition of uniconazole to the priming solution had no significant effect on speed of emergence or total emergence after 12 days compared to the primed control. Seed priming plus uniconazole at 1 or 10 mg·liter-1 reduced seedling height after 2 weeks by ≈ 20% compared to the primed control. Uniconazole had no effect on the mortality of either hardened or nonhardened seedlings exposed to below-freezing temperatures for 3 hr. These data suggest that treatment of tomato seed with hypertonic solutions containing uniconazole would be of little practical value in protecting seedlings from freeze damage. Chemical names used: (E)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-yl)penten-3-ol (uniconazole).
Abba Upadhyaya, Tim D. Davis, Daksha Sankhla, and N. Sankhla
Both kinetin and BA promoted in vitro shoot formation from hypocotyl explants of Lupinus texensis Hook. placed on Murashige and Skoog (MS) medium. With either cytokinin, shoot formation was best at ≈4.5 μm. Adventitious root formation was observed only on tissue culture-derived shoots placed in MS media containing 5.4 to 54 μM NAA. IAA and IBA, at concentrations ranging from 5 to 55 μm, failed to stimulate rooting. Even at the optimal concentration of NAA, only 14% of the shoots produced roots. Thus, although hypocotyl explants readily produced shoots, adventitious root formation on these shoots occurred with relatively low frequency. Chemical names used: 6-benzylaminopnrine (BA); indole-3-acetic acid (IAA); indole-3-butyric acid (IBA); 6-furfurylaminopurine (kinetin); 1-naphthaleneacetic acid (NAA).
Tim D. Davis, Wayne A. Mackay, and N. Sankhla
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.
Tim D. Davis, Wayne A. Mackay, and Daksha Sankhla
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.
Jo Ann Robbins*, Susan Bell, Tim Davis, and Kevin Laughlin
Master Gardener training was first offered in Idaho in 1976. Univ. of Idaho (U of I) Master Gardener trainings are held in various counties and organized by county extension faculty. The number of Master Gardeners in Idaho is estimated at 1800. In 1993, U of I published the first edition of the Idaho Master Gardener Handbook. This 23-chapter state-specific handbook is revised annually. The first chapter outlines the Idaho Master Gardener guidelines. These were the first statewide guidelines. The Idaho program requires a minimum of 30 hours of classes and 30 hours of practicum/hands-on training (the volunteer commitment). Certification is received after these requirements are met and is good for one year. Annual recertification is provided through participation in Advanced Master Gardener trainings and activities. These recertification programs differ; depending on wants and needs within Idaho. The U of I Horticulture Programming Topic Team loosely organizes all county efforts, but there is no statewide Master Gardener program in Idaho. Each region and county brings a unique framework to the title Master Gardener. Hands-on training in many counties includes problem solving services to phone and office visiting clients. Other horticultural community and extension projects are the balance of the hands on hours. Idaho Master Gardeners also serve as uniquely qualified educators in a state as geographically diverse as Idaho. In 2001, the Idaho Junior Master Gardener Program began in cooperation with Idaho Master Gardeners and Texas A&M Univ.. Over 2000 youth and 200 adults have been involved in Idaho.
Michael A. Arnold, Tim D. Davis, and David W. Reed
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.
Daksha Sankhla, Tim D. Davis, N. Sankhla, and A. Upadhyaya
A variety of Hamelia patens (firebush) explants (nodal and internodal segments, leaf blade pieces, floral buds, shoot tips) were cultured on Murashige and Skoog's revised medium containing various concentrations of 2,4-D and kinetin. Embryogenic callus was produced only from shoot-tip explants placed on media containing 2,4-D or 2,4-D plus kinetin. None of the other explants produced embryogenic callus. Somatic embryogenesis from callus was greatest on media containing both 2, 4-D and kinetin. Direct somatic embryogenesis was observed on the roots of callus-derived primary embryos maintained on media containing 2,4-D or 2,4-D plus kinetin. Conversion of somatic embryos into plantlets only occurred on media containing 2,4-D, kinetin and activated charcoal.
Michael A. Arnold, Tim D. Davis, and David W. Reed
A group of 53 institutions of higher education in the United States and Canada offering degrees in horticulture, or closely related plant science degrees, was surveyed to determine various characteristics associated with the degree programs offered, demographics of students and faculty, and selected procedures and practices associated with administration of these graduate programs. Total response rate was 94%, yielding 85% usable completed surveys. Very few programs (0-3 per degree type) were offered via distance education and on average only 4.1% to 4.5% of resident instruction program students participated in distance education courses. Domestic students averaged 64% to 75% of enrollment. Students were 69% to 73% white. Asian students were the predominant minority group at 12% to 16% of enrollment, followed by African Americans (3% to 8%) and Hispanics (1% to 4%). Most institutions provided out-of-state tuition waivers (75%), and often in-state-tuition waivers (61%), to those students on assistantships or fellowships. Typical commitments to students were 3 years for a PhD and 2 years for a master's degree program. Research assistantships were the dominant form of assistance at all institutions (38% to 53% of students), while teaching assistantships contributed significant secondary funding (7% to 13%). With the exception of mean maximum fellowships, mean maximum assistantships ($11,499-$13,999) at non-1862 Morrill Act universities (NMAU) averaged near the mean minimums ($13,042-$14,566) for the corresponding assistantship types at 1862 Morrill Act universities (MAU). Requirements for teaching experience ranged from 41% of PhD programs to 18% of non-thesis master's degree programs. Typical departments contained 29 faculty members, of which 44% were full professors, 27% associate professors, 19% assistant professors, 6% junior or senior lecturers, and 3% were in other classifications. Traditional 12-month appointments (65.9% of faculty) were predominant at MAU. With the exception of junior lecturer positions, mean salaries at MAU averaged $9125, $6869, $8325, and $28,505 more for professor, associate professor, assistant professor, and senior lecturer, respectively, than at NMAU. This study provides useful information for departments undergoing external review or revision of graduate programs.