Shade is one of the most important factors affecting turfgrass growth for home lawns. It affects both shoot and root growth and the overall quality of the turf stand. A study was initiated to investigate the effects of shade on growth and quality of St. Augustinegrass (Bitterblue, Delmar, Floratam, Palmetto, Raleigh, Seville, andTR-610) and two cultivars of zoysiagrass (Empire and Empress) were planted in both the shade and sun to study the effects on growth and quality. Quality measurements were taken for color, texture, density, uniformity, and overall quality on a monthly basis. Growth parameters were taken for internode length , stolon width, leaf width, and leaf length during initial, middle, and final stages of the study period. TR-610 was the best cultivar under shade for its outstanding quality in color, density, uniformity, and overall quality. Delmar, Palmetto, and Raleigh performed relatively better in shade compared to other cultivars. Empire and Empress zoysiagrasses had good quality until the middle of the study period but quality decreased toward the end of the study. The quality of Empire was relatively better compared to Empress at the end of the study period. Bitterblue and Floratam did not perform well in the shade. TR-610 showed shade tolerance by performing similarly in both shade and sun for all the growth parameters. Bitterblue had poor shade tolerance compared to the other cultivars. It had longer internodes, thicker stolons, and wider leaf blades in shade during the study period. Floratam was relatively better compared to Bitterblue. Reduced internode length, optimum stolon and leaf width, and increased leaf lengths were identified as the shade tolerant characters.

The effects of summer soil solarization on the production and economics of four lettuce cultivars were evaluated in two plantings conducted during the fall growing season of 2001, to determine the feasibility of integrating strip-solarization in plasticulture cropping systems. Soil was solarized for 53 and 34 days for the first and second plantings, respectively, using transparent (T4, T5) and black films (T6) that were kept in place as plastic mulches in raised beds through the fall season. Soil temperatures were recorded at 5 and 10-cm depths at 1-hour intervals during the solarization period. Mulch on T5 was painted black before planting the crop using diluted oil-based paint. Non-solarization treatments included bare ground (T1), fall black plastic mulch (T2) and fall plastic mulch + soil pesticides (T3). Soil pesticides applied on T3 during the first and second plantings were Mefenoxam (MEF) and a mixture of 1,3-Dichloropropene and Chloropicrin (TC-35), respectively. Temperature regimes below clear and black plastic mulches were equivalent, although clear film consistently showed longer periods of sustained high temperatures. Solarization with clear and black mulches equally increased lettuce yield by enhancing plant growth and head weight, as plant stand was uniform for all the treatments. MEF did not affect yield, and TC-35 decreased head weight due to phytotoxicity. Solarization reduced weed densities, especially from grasses. Enhanced weed suppression was achieved by using black plastic for solarization and mulching. MEF increased weed populations while TC-35 caused maximum weed suppression. Cost analysis revealed that yield increases required to cover solarization expenses in bare-ground and fall-mulch systems are generally lower than yield increases reported in previous solarization research.

Concerns over the adverse effects of pesticides on human health and the environment have led to the development of stricter pesticide regulations and the outright banning of many pesticides in the U.S. Bifenthrin and fipronil are important pesticides used in the nursery industry for the control of imported fire ants (Solenopsis invicta Buren, S. richteri Forel, and their hybrids) to meet the requirements of the Imported Fire Ant Quarantine. Nurseries typically use highly-organic media ("soilless" media) and little is known about the fate of these pesticides when used with these media. Our research measured the influence of irrigation frequency and time on the degradation of bifenthrin and fipronil in a nursery medium composed of 90% pine bark and 10% mason sand. Media samples and media leachate samples were collected over a period of 180 days. Levels of bifenthrin, fipronil, and fipronil metabolites (MB45950, MB46136, MB46513) were measured using gas chromatography with electron capture detection (GC/ECD) and gas chromatography secondary ion mass spectrometry (GCMS/SIMS). Bifenthrin levels in the nursery potting media initially dropped and then remained constant throughout the study. Fipronil levels in nursery potting media decreased over time. Levels of the fipronil metabolite MB45950 in potting media fluctuated over time, while the levels of this metabolite increased over time in media

Six different planting depths and mulch treatments were applied to nine different species of landscape plants in a field study beginning July 5, 2001. Plants were maintained for a two-year study period on the effects of improper planting depths and mulch on the following species; Southern Magnolia Little Gem (Magnolia grandiflora), Bald Cypress (Taxodium distichum), Crape Myrtle (Lagerstromia indica x fauriei Natchez), Azalea (Rhododendron indicum George L. Tabor), Indian Hawthorn (Raphiolepis indica Clara), Loropetalum (Loropetalum chinense Burgundy), Dwarf Gardenia (Gardenia jasminoides Radicans), Dwarf Nandina (Nandina domestica Fire power), and Liriope (Liriope muscari Big Blue). Four growth indexes, and quality ratings were collected over this study. A second experiment was conducted on the same plant species in a container study that involved three different planting depths. Growth index measurements were taken four times over an eight-month period, and shoot and root dry weights were also collected. This research will help to determine the tolerances of these nine species to improper planting techniques and mulch. For this study the following planting depths were used in the field were 7.6 cm above grade, 3.8 cm above grade, at grade, 3.8 cm below grade and 7.6 cm below grade. One half of the plants in the field were mulched at a rate of three-inches with 5/8th screen pine bark mulch. In the container study the following planting depths were used: at grade, 3.8 cm below grade, 7.6 cm below grade. For all species, growth did not differ among the planting depth treatments in the field. However, there was a significant affect by the application of mulch on seven of the eight species in the field study. In the container study, significant affect of planting depth was observed in all species except bald cypress, Indian hawthorn, and dwarf gardenia.

Influence of media age, initial dark period, inoculation with Agrobacterium, and leaf maturity on the regeneration and genetic transformation of two strawberry cultivars was investigated. Four cultivars of blackberry and one raspberry were included to test their response to media age and dark period. Leaf strips of Chandler and Cardinal strawberry, blackberry, and raspberry were exposed to a four-week dark treatment on modified MS media and subcultured to fresh media. One group of leaf strips was left on the original media for the entire eight weeks. Another group of explants, along with the media treatments was given an additional four-week dark period. Chandler strawberry leaf strips exposed to four weeks dark and subcultured onto fresh media produced 19% more plantlets than Chandler exposed to eight weeks dark. Chandler given a four-week dark period and subcultured onto fresh media produced 58% more plantlets than those left on their original media. Chandler produced 97% more plantlets than Cardinal strawberry produced with any treatment. Cardinal strawberry, blackberry and raspberry responded by producing copious amounts of callus. When inoculated with Agrobacterium, the highest regeneration rate for Chandler or Cardinal strawberry leaf strips was less than 0.2 plantlets per leaf strip. This was a 96% reduction in regeneration rate compared to the previous experiment in which Agrobacterium was not introduced. In an experiment to test the effect of leaf maturity on regeneration rate, 59% more plantlets were produced from unexpanded strawberry leaf strips than leaf strips from newly expanded or mature leaves. Unexpanded Chandler strawberry leaf strips, exposed to a four-week dark period followed by subculturing onto fresh media, have a higher regeneration rate than those given an eight-week dark period or left on their original media. Chandler strawberry leaf strips from unexpanded leaves have a higher regeneration rate than those from newly expanded or mature leaves.

Two horticultural crops, the ornamental liriopogon and the sweetpotato [Ipomoea batatas (L.) Lam.], were analyzed for morphological, quantitative and molecular marker variation using Amplified Fragment Length Polymorphism (AFLP) and various multivariate statistical techniques. Ornamental cultivars in genera Liriope and Ophiopogon were analyzed for relatedness using AFLP marker data and statistical clustering methods. Marker data did not substantiate the separation of these two genera. Greater than 95 % of the total genetic variability present was attributed to within group variation (P < 0.05). Trait-linked molecular markers were identified using Quantitative trait loci (QTL) analysis, logistic regression and discriminant analysis in the studies involving sweetpotato. The traits studied included dry matter content, virus disease resistance, root-knot nematode resistance, sugar content and -carotene content. Analysis of molecular variance found significant (P <0.001) differences between two phenotypic groups from unrelated genotypes for dry matter data. Using 14 markers selected through discriminant analysis the phenotypic grouping was validated with a zero error rate. Eighty-seven F1 sweetpotato genotypes from a cross of Tanzania and Wagabolige landraces were used to generate AFLP and random amplified polymorphic DNA (RAPD) marker profiles for this study. One AFLP marker linked to sweetpotato chlorotic stunt closterovirus resistance and one RAPD marker linked to sweetpotato feathery mottle virus resistance previously identified by traditional mapping strategies were selected plus new markers. Two diverse F1 populations of sweetpotato were used to identify and select markers suitable for identification of plants possessing a resistant reaction to southern root-knot nematode race 3 [Meloidogyne incognita (Kofoid and White) Chitwood]. Results for plant nematode resistance indicated a binomial distribution among the genotypes for population 1 and a normal distribution for population 2. A comparison of the power of discriminant analysis models for southern root-knot nematode resistance class prediction achieved 88% classification efficiencies. An F1 population of 73 clones consisting of parents and half-sibs was grouped into 2 phenotypic classes based on their sugar and ß-carotene content. Logistic regression and discriminant analysis selected meaningful markers that had significant associations with each of the traits. These results validated discriminant analysis and logistic regression as meaningful trait-linked marker selection methods.

Louisiana is losing nearly 34 square miles of coastal land each year. Scientists predict by 2050 one-third of Louisianas coast land will disappear (LaCoast, 2004). Many restoration projects have begun to counteract the severe land loss. Scientists use restoration methods such as vegetative plantings, sedimentary and freshwater diversions, and hydrologic projects to prevent land loss. Coastal Roots, a school-based nursery stewardship project for upper elementary to high school students coordinated by Louisiana Sea Grant College Program and LSU AgCenter, helps students understand the land loss crisis and gives them a constructive way to help restore the damaged coastal habitats by providing student-grown plants for vegetative plantings. Because of the critical role that horticulture practices play in raising seedlings into mature transplants, eight standards-based horticulture lessons were created and taught in middle school classrooms at four schools over a period of two years. Ultimately, these eight lessons will (1) provide the science content and skills students need in order to be able to grow healthy seedlings, and (2) increase students awareness and concern about coastal land loss issues facing the citizens of Louisiana. The eight middle school science lesson plans were created to meet specific Louisiana Grade-Level Expectations for 463 students in 4 schools. Pre and Post-tests were given to each participating class (six grade through nine) in addition to the Childrens Attitude Towards the Environment Scale (CATES). Additional pre- and post-tests were given to selected classes not participating in the program. The evaluations tested both short and long-term memory on material contained in the lesson plans. The data was analyzed by school, gender, treatment, and grade level. Results for both 2003 And 2004 general science knowledge increased an average of greater than 20%. Long and short-term memory test indicated individual higher scores for the students who were instructed in this program compared to the control students. The Childrens Attitude Towards the Environment Scale or CATES indicated a significant increase in environmental awareness in participating students.

The effect of growth regulators gibberellic acid (Pro-Gibb), daminozide (B-Nine), ancymidol (A-Rest) and paclobutrazol (Bonzi) were evaluated on species of Clerodendrum grown as flowering pot plants. Studies on photoperiod and post-production longevity were also included. Experiments were conducted on C. bungei, C. thomsoniae, C. ugandense, C. phillippinum, C. paniculata and C. speciosissimum in polycarbonate greenhouses. For C. thomsoniae the best growth control was achieved by applying paclobutrazol and ancymidol drench at a rate of 1.0 mg a.i. /pot. For C. ugandense, the most appropriate application rate of PGR was paclobutrazol drench at 5 to 15 mg a.i./pot. C. bungei did not respond significantly to either daminozide or paclobutrazol treatments compared to control. Based on the visual quality rating, C. bungei were acceptable as marketable plants until day 7, and C. ugandense were acceptable as marketable plants until day 5. Neither daminozide nor paclobutrazol had any effect on C. bungei quality ratings in post-production. In C. ugandense, however, there were significant differences in post-production when comparing the daminozide and the paclobutrazol treatments. On day 5, 7 and 11, the paclobutrazol treated plants had significantly lower quality ratings compared to control and compared to those treated with daminozide. It appears that the paclobutrazol treatment may produce a quality plant, but has a negative effect on post-production longevity. Gibberellic acid at 10 ppm was considered the best rate and most economical rate for promoting optimum vegetative growth of C. thomsoniae to sufficiently cover a round support hoop. C. speciosissimum, C. phillippinum, C. paniculata and C. speciosissimum were determined to be long day plants (12-h photoperiod or longer). Height of C. paniculata and C. speciosissimum was significantly increased by the 12 or 16-h photoperiod.

Effects of P and K fertilization on Tabasco plant growth and fruit quality were evaluated in a preliminary experiment conducted in fall 2002; 4 levels of P (0.25, 1.0, 1.75, and 2.5 mM) and 4 levels of K (0.75, 1.75, 2.75, and 3.75 mM) in hydroponic culture with a factorial randomized design. The main growth experiment was conducted in spring/summer growing period of 2003. This experiment consisted of 8 treatments; 4 levels of P (P1 0.25, P2 1.25, P3 2.5, and P4 3.75 mM) and 4 levels of K (K1 0.25, K2 1.25, K3 2.5, and K4 3.75 mM). The same treatments were used to evaluate fruit quality characteristics in an experiment conducted simultaneously. Tabasco pepper "McIlhenny Select" seed were sown in trays; at the fourth true leaf stage, individual plants were transplanted into 3-gallon round plastic pots filled with agricultural grade perlite. Plants were harvested once every month; stem diameter and plant measurements were taken every fifteen days. The Preliminary growth experiment showed that P affected plant height, leaf area, root, stem and leaf dry weights as well as overall plant dry weight. Potassium affected root dry weight at both harvests with no influence on other growth variables. Dry root weights of plants grown with the highest K rate (K4) were significantly higher than the lowest k rate (K1). Potassium source was changed for the main plant growth experiment. Phosphorus and potassium rates significantly affected plant growth, increasing height, weight, stem diameter, leaf area, and dry weights of plant sections with increasing rates in nutrient solution. For fruit quality experiment, all plants grew until the flowering stage with the same nutrient solution (2 mM P; and 3.75 mM K). At the beginning of the flowering stage different nutrient treatments were applied. Increasing P and K rates also affected plant yield and some fruit quality variables. Results were consistent for most of the variables, suggesting that the 0.25 mM concentration for both P and K was insufficient for pepper production. Concentrations higher than 1.25 mM and close to 2.5 mM are the most appropriate for hydroponic tabasco pepper production.

One of the greatest impediments affecting growth and development of bedding plants is high temperature stress. The deleterious effects of high temperature stress are the most pronounced during plug transplant and/or during the transition period from the nursery to the landscape. High temperature stress responses were investigated in Salvia splendens and Viola x wittrockiana to determine the morphological and physiological mechanism associated with the heat tolerance. Two genotypes for each species were used; a heat tolerant Vista and a heat sensitive Sizzler cultivar of salvia and Crystal Bowl Purple (CBP) a heat tolerant and Majestic Giant Red (MGR) a heat sensitive cultivar of pansy. Morphological traits such as short stature, greater total leaf area/plant, extensive root system; physiological traits like stomatal conductance, greater transpiration, and net photosynthesis were found to be characteristic traits of heat tolerant cultivars. Greater cell membrane thermostability (CMT) and expression of a heat shock protein of low molecular weight approximately 27kD may be responsible for heat tolerance in Vista and CBP. Primary soluble sugars sucrose and raffinose found in both the salvia cultivars, and greater concentrations in Vista at high temperatures, may be involved in stabilization of membrane lipid bilayer and/or acting as osmoprotectants under stress conditions. Short duration (3 h) heat preconditioning at 35 °C and 30 °C for salvia and pansy respectively during initial stages of growth helped to develop acquired thermotolerance. Heat sensitive cultivars acquired heat tolerance with heat preconditioning and acclimated to subsequent challenging temperatures. Preconditioning enhanced already existing traits of heat tolerant cultivars. Increased stomatal frequency and leaf thickness in salvia acquired during preconditioning. Cell membrane thermostability measured at a single temperature with increasing time of exposure was closely associated with increased gas exchange rates, leaf relative water content and overall marketable quality in salvia. These simple laboratory techniques to test heat tolerance have a greater advantage over time and space consuming field trials and may be an accurate and more efficient measure of heat tolerance.