This study was initiated to test the embryogenic potential of immature cotyledons (3-5 mm long) of Texas bluebonnet (Lupinus texensis). The embryo initiation medium consisted of B5 salts and vitamins with 3% sucrose and 22.6 μM 2,4-D alone or in combination with 1-15 μM of various cytokinins. Within 15-20 days, globular embryos were formed on the distal end of the cotyledons. Eventually the entire cotyledon surface was covered by embryo-like structures. Addition of cytokinins to the medium did not increase the percentage of cultures which formed embryos. In fact, addition of thidiazuron severely inhibited embryogenesis. Following transfer to an embryo maturation medium (MS medium with 0.38 μM abscisic acid alone or in combination with benzyladenine or zeatin) for 10-14 days, the embryos were placed in MS medium supplemented with GA (2.9 μM) or glutamine (200 mg/liter) with or without activated charcoal (0.5%) for embryo germination and plantlet development. Most of the embryos exhibited precocious germination and well-developed roots but failed to produce normal shoots. Therefore, additional work is needed to improve embryo conversion frequency.
Daksha Sankhla, Tim D. Davis, and N. Sankhla
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.
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.
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.
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.
Tim D. Davis, Eric M. Bost, and Carmen N. Byce
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.
Tim D. Davis, Wayne A. Mackay, and Narendra Sankhla
Big Bend bluebonnet (Lupinus havardii Wats.) is native to a narrow geographic range in southwestern Texas and produces attractive blue inflorescences (racemes) that may be used as cut flowers. Several crops were produced in the greenhouse to determine postharvest-characteristics of the cut inflorescences. Without any postharvest conditioning treatments, the inflorescences held in water had an average vase life of about 7 days. During this period, an average of 13 flowers abscised per inflorescence. When preconditioned for 4 hours in 40 to 160 mg·liter−1 silver thiosulfate (STS), vase life increased to 10 to 12 days and fewer than three flowers abscised per inflorescence. A commercial floral preservative (Oasis) had no effect on flower abscission or vase life of STS-treated inflorescences. Flower abscission and vase life were the same whether STS-treated inflorescences were placed in floral foam moistened with water or in water alone. Storing STS-preconditioned inflorescences in water at 5C for 72 hours did not affect flower abscission or vase life compared to the unstored control. Dry postharvest storage at 5C for 72 hours caused noticeable wilting, but, on dehydration, these inflorescences still had a vase life of about 8 days. Postharvest characteristics of pink-and white-flowered breeding lines were the same as for the blue-flowered line. These results indicate that cut inflorescences of L. havardii have desirable postharvest qualities and can be stored for up to 72 hours without seriously limiting vase life.
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).