Search Results

You are looking at 1 - 6 of 6 items for

  • Author or Editor: Milton E. Tignor Jr x
Clear All Modify Search
Free access

Milton E. Tignor Jr. and Elizabeth M. Lamb

The Univ. of Florida has had off-campus degree programs for over a decade. In 1998, a new program in a major agricultural region of the state developed under unique circumstances. Community driven support, leadership from local politicians, and guidance from academic administrators resulted in the legislative funding of a new undergraduate teaching program in south Florida. The program offers upper-division courses leading to Bachelor of Science degrees in horticultural science and food and resource economics. Another unique aspect was the partnership formed with local universities necessary to offer the degrees. Locally, Indian River Community College provides lower-division courses and Florida Atlantic Univ. offers four upper-division courses to complete the course offerings for the degrees. Funding was allocated for eight new faculty members with 70% teaching appointments, four support staff, and a new $3.7 million teaching complex. In today's academic climate, having eight new faculty members at one time is a rare occurrence that allowed for creative growth on the part of the new teaching program. What was successful and unsuccessful concerning recruitment, advertising, purchasing, advising, collaborative efforts with local colleges, and administration will be discussed. In addition, demographics on the student body will be presented.

Free access

Milton E. Tignor Jr. and Courtney A. Weber

Current efforts in the study of citrus freeze hardiness including gene mapping and elucidating early induction processes require large populations of uniform seedlings. Related genera and intergeneric hybrids are often used in these studies and little is known about factors effecting their seedling emergence. We tested a total of 8 genotypes including Poncirus trifoliata `Rubidoux', Citrus grandis, C. sinensis `Pineapple', C. jambhiri `Schaub', C. paradisi `Duncan', C. aurantium (Brazilian), Carrizo citrange (P. trifoliata × C. sinensis), and Troyer citrange. A total of seven pre-planting treatments were used to evaluate seedling emergence rates. Expanding on the work of previous researchers, treatments were seed coat removal, hydrating in water (96 hours) at either 4, 25, or 35°C, acid scarification, or boiling. Generally, seed coat removal resulted in the most uniform emergence as compared to untreated controls. Presoaking at each temperature enhanced emergence in most varieties tested and 25°C was the best hydrating temperature. Acid scarification greatly delayed emergence in all genotypes tested except Troyer citrange and `Pineapple' orange which had enhanced emergence rates as compared to controls. Preplanting treatment with 100°C water was lethal in all varieties. Pretreatment of citrus seeds can enhance uniformity of germination, although optimum treatments for individual genotypes vary.

Free access

Milton E. Tignor Jr. and Russell L. Weiser

Alaska peas (Pisum sativum `Alaska') were germinated in the dark at 25C. After three days, when the shoots were approx. 1.5 cm, treatments were initiated. ABA, at 10-4M, was exogenously applied through the root solution. The control peas remained in distilled water. All treatments involving the application of ABA were applied under green safe light. Light treatments were applied using overhead fluorescent lights for designated timed intervals (0 to 20 min) over 3 days. A methanol bath was then used to induce freezing stresses from 0 to -9C. The combination treatment of light and ABA had the lowest LT50 (more cold tolerant) followed by light, dark, and dark with ABA (least cold tolerant). Extensin levels, plant growth, and stem bendability were also recorded.

Free access

Milton E. Tignor Jr. and Russell L. Weiser

Alaska peas (Pisum sativum `Alaska') germinated in a dark growth chamber were treated ABA dissolved in a small amount of acetone before diluting in distilled water with 0.1% spreader. A blank solution was identically prepared without ABA. Both solutions were applied via paintbrush to the epicotyls of the peas every twelve hours for seven days following emergence. The blank solution was applied to two controls, chronological and physiological. A methanol bath was used to induce freezing and chilling stresses. ABA significantly improved cold tolerance (electrolyte leakage) in the pea seedlings for both freezing and chilling stress as compared to the physiological and chronological controls. Visual observation of the pea stems suggested a difference in stem flexibility among ABA treated peas and the controls. Pea stem elasticity and plasticity were measured along with plant dry weight, cell wall weight/gram fresh weight, and the quantity of cell wall sugars and amino acids.

Free access

Milton E. Tignor Jr., Frederick S. Davies and Wayne B. Sherman

Citrus hybrids USDA 17-11 [Citrus grandis L. × (C. paradisi Macf. `Duncan' × Poncirus trifoliata (L.) Raf. `Gotha Road')] and 119 [(C. paradisi Macf. `Duncan' × P. trifoliata (L.) Raf. `Gotha Road') × C. sinensis (L.) Osb. `Succory'], `Hamlin' orange [C. sinensis (L.) Osb.], and satsuma mandarin (C. unshiu Marc.) were planted March 1993 and 1994. Trees were irrigated and fertilized in an identical manner. In 1993, electrolyte leakage readings were taken monthly using 17-11, 119, and satsuma leaf discs. Leaf killing point (LKP) LT50 averaged from –8 to – 9C by mid-November for all selections. In 1994, leaf discs from 17-11, 119, and `Hamlin' orange were sampled weekly to determine LKP. USDA 119 had the lowest LKP and acclimated the fastest during the fall. By the end of November, there was no significant difference in LKP (–6.5C) between USDA 119 and 17-11, although both selections were significantly more freeze-tolerant than `Hamlin' orange (LKP–40C), which showed no significant decrease in LKP until the 6 weeks after the hybrid selections began acclimating. Citrus hybrids 17-11 and 119 can survive in freeze-susceptible areas that are marginal for other commercial citrus.

Free access

Milton E. Tignor Jr., Frederick S. Davies and Wayne B. Sherman

`Hamlin' orange trees [C. sinensis (L.) Osb.] from a commercial nursery were planted into raised beds on a site that simulated conditions typical of the flatwoods region of the citrus industry. A factorial experiment with three irrigation schedules, based on growth flushes and three nutrient application frequencies (total N, 0.136 kg/tree per year), was conducted in 1994. Trees were irrigated using 90° microsprinklers, and soil moisture content was monitored using a neutron probe. Eleven replicate trees of the nine treatments were included in a completely randomized block design. Weekly freeze tests using the electrolyte leakage method were conducted at –4, –6, and –8C. Electrolyte leakage was determined using a conductivity meter. Different irrigation scheduling based on growth flushes had no significant effect on freezing acclimation. However, increased frequency and lower amounts of fertilizer per application significantly (P = 0.05) increased freeze hardiness from 4.2 to –6.10C by the end of November. Morphological data including trunk diameter, tree height, and flushing status also were recorded. Increasing frequency of nutrient application resulted in a more rapid acclimation of young `Hamlin' orange trees.