Stilbene concentration was analyzed in juice and tissue of muscadine grape (Vitis rotundifolia Michx.) and bunch grape (Vitis labrusca L.) from fresh fruit, after processing and after postharvest treatments. Five filter types were evaluated for percent resveratrol recovery when filtering standard and spiked juice samples in preparation for HPLC analysis. Only two (polycarbonate and Anopore) of the five filter types had more than 90 percent recovery. Polycarbonate was chosen for sample preparation since it was more durable during handling. Eight muscadine grape cultivars and three bunch grape cultivars were evaluated. Skin tissue had approximately 100 times higher stilbene concentration than did the pulp for all cultivars studied. Carlos and Magnolia muscadine cultivars had the greatest skin stilbene concentration of all the muscadine cultivars evaluated. Except for Sweet Jenny, bronze cultivars had greater skin stilbene concentration than black skinned cultivars. Miss Blanc Vitis labrusca grape had greater skin stilbene concentration than all other cultivars. Stilbene concentration of fresh juice extracted from Noble and Carlos muscadine grapes was relatively low compared to processed juices. Juices obtained using hot press and freezing methods of juices extraction had significantly higher stilbene concentration than free run or cold pressed juice. Although Carlos skin tissue had significantly more stilbenes than Noble skins, there were no significant differences between free run, cold press or hot press juices obtained from the two cultivars. Although pectic enzyme treatment significantly increased juice yields, stilbene concentrations were not significantly higher than other juice extraction methods. In contrast to Carlos muscadine grape, where high skin stilbene concentration did not result in high juice concentration, Vitis labrusca grape juices had relatively high stilbene concentration when compared to muscadine juices. UV irradiation and cold storage had a significant effect on stilbene concentration of muscadine grape tissue. For Carlos muscadine grape, cold storage alone doubled skin stilbene concentration, but UV irradiation did not significantly change stilbene levels. In contrast, in Noble muscadine grape, UV irradiation increased skin stilbene concentration by 50%, but cold storage alone had no effect.

Bark is a renewable resource with limited availability as a medium used by the nursery industry. Previous research has indicated that pinebark and hardwood bark can be used as a substrate in nursery production. The objective of this study is to determine the effect of bark source (pinebark and hardwood bark), particle size distribution, and irrigation frequency on the growth and quality of azalea (Rhododendron indicum Red Ruffle), Indian hawthorn (Rhapeolepis indica Snow), and ligustrum (Ligustrum japonicum). Treatments were arranged in a factorial 6x2x2 plot design, with six soil mixes, two barks, two irrigation frequencies, and six blocks totaling 144 replicates. Treatments were arranged using a randomized complete block design. Pinebark and hardwood bark sources were sieved into four different categories using sieves 3.35mm (#6), 1.4mm (#14), 710µm (#25), and < 710µm (<#25) to establish uniform physical characteristics. Six treatments were established to provide media mixes of small, medium, and large particle size distributions. Irrigation treatments were based on the effluent collected after irrigation. Treatment 1 maintained an effluent level of 20 to 40%, while Treatment 2 maintained an effluent level of 10 to 20%. Results indicate that hardwood bark pH and EC were significantly greater than pinebark, although differences were minor (0.3 and 0.1 increase, respectively). Quality ratings of azalea, Indian hawthorn, and ligustrum were significantly greater in pinebark compared to hardwood bark (32%, 17%, and 33% increase, respectively). Also, growth index and shoot weights for azalea, Indian hawthorn, and ligustrum were significantly greater in pinebark compared to hardwood bark. Growth indexes increased 25%, 13%, 39%, respectively, and shoot weights increased 58%, 27%, 72%, respectively. Media treatment 3 (3.35mm, 710µm, < 710µm) produced the greatest shoot weights and growth index for azalea in pinebark. Media treatment 2 (3.35mm, 1.4mm, < 710µm) produced the greatest shoot weights, growth index, and quality ratings for Indian hawthorn and ligustrum. Hardwood bark particle size distribution had no significant effect on shoot weights, growth index, or quality ratings. Irrigation treatment 2 (low volume) significantly increased the values of EC and pH for all three plants.

Media amendments can be added to pinebark to increase its water holding capacity. Hydrogels are amendments which can hold 20 to1000 times their weight in water. The objective of this study is to determine the effects of media and a hydrogel on the post-harvest quality of ornamentals likely to have poor post-harvest quality in the retail nursery setting. The selected species were Buddleia davidii Nanho Blue, Salvia leucantha and Verbena x canadensis Homestead Purple. Treatments were arranged in a randomized complete block design. It consisted of eight replications of three species, three media treatments and a hydrogel amendment for two planting dates and three retail nursery settings, totaling 576 pots. The three media were 100% pinebark, 9 pinebark:1 peat and 9 pinebark:1 sand. The hydrogel was applied post-harvest, to a portion of the plants grown in 100% pine bark. Once harvested, plants were transferred to three retail nursery settings where they remained for 4 months. There were differences in specie response to the different media. At the end of production, growth for Salvia leucantha was similar except for plants assigned to one retail nursery setting, where pinebark:peat and pinebark:sand had the highest growth indices. Buddleia davidii Nanho Blue had the highest growth index in pinebark:peat for plants assigned to two retail nursery settings. Verbena x canadensis Homestead Purplehad the highest growth index in pinebark and pinebark to be amended with hydrogel assigned to one retail nursery setting. The hydrogel increased growth index of Buddleia davidii Nanho Blue by 13% at one retail nursery setting and maintained plant quality at another retail nursery setting, where it increased dry shoot weight by 46% and 103.8% for crop 1 and crop 2 respectively. For Salvia leucantha, the hydrogel increased growth index in two retail nursery settings by 5% and 19%, and maintained plant quality in two retail nursery settings. For Verbena x canadensis Homestead Purple, the hydrogel increased dry shoot weight by 72%, and maintained the best plant quality in one retail nursery setting. Overall plant quality was lowest at the two retail nursery settings where the irrigation water had a higher alkalinity.

The influence of numerous factors on sweetpotato phenolic content and antioxidant activity was determined. Simplified, robust, and rapid methodologies were developed to quantify total phenolics and individual phenolic acids in sweetpotatoes. Quantification of total phenolic content using Folin-Denis reagent provided more reliable results than Folin-Ciocalteu reagent. Individual phenolic acids were quantified by reversed-phase high performance liquid chromatography (HPLC) and the best separation was achieved using a 5-µm, 4.6 × 250 mm column with a mobile phase of 1% (v/v) formic acid aqueous solution: acetonitrile: 2-propanol (70:22:8), pH 2.5. Methanol and ethanol provided higher phenolic extraction efficiency than acetone. In general, chlorogenic and 3,5-dicaffeoylquinic acid were the most prominent phenolics acids in sweetpotato root and leaf tissues. Immature roots and leaves at the initial stages of growth had the highest concentration of phenolics and antioxidant activity. In a comparison of plant parts, sweetpotato leaves had a significantly higher phenolic content and antioxidant activity than roots. Thermal processing of sweetpotato storage roots resulted in a significant loss of phenolic content and antioxidant activity. The outer skin tissue (raw or processed) contained the highest amounts of phenolic acids but also exhibited higher losses than cortex or pith tissue. After a 4 week exposure to 5 °C, the rate of increase in phenolic content and antioxidant activity in non-cured sweepotatoes was significantly higher than in cured roots. An ambient temperature exposure following low temperature storage accentuated the increase in phenolics and antioxidant activity. Minimally processed sweetpotatoes held at 5 °C accumulated more phenolic compounds and had a higher antioxidant activity than sweetpotatoes held at 0 °C. The increase in total phenolic content and antioxidant activity after 8 days was higher than 4 days. No fresh-cut tissue browning was observed after 8 days and the products were considered to be marketable. Sweetpotato genotypes differ in their phenolic content and antioxidant activity. A purple-fleshed breeding line was found to have higher total phenolic content and antioxidant activity than orange-fleshed and white-fleshed cultivars.

Microarray protocols were developed for sweetpotato (Ipomoea batatas (L.) Lam.) and then used to study issues of importance in sweetpotato physiology and production. The effect of replication number and image analysis software was compared with results obtained by quantitative real-time PCR. The results indicated that reliable results could be obtained using six replicates and UCSF Spot image analysis software. These methodologies were employed to elucidate aspects of sweetpotato development, physiology and response to virus infection. Storage root formation is the most economically important process in sweetpotato development. Gene expression levels were compared between fibrous and storage roots of the cultivar Jewel. Sucrose synthase, ADP-glucose pyrophosphorylase, and fructokinase were up-regulated in storage roots, while hexokinase was not differentially expressed. A variety of transcription factors were differentially expressed as well as several auxin-related genes. The orange flesh color of sweetpotato is due to β-carotene stored in chromoplasts of root cells. β-carotene is important because of its role in human health. To elucidate biosynthesis and storage of β-carotene in sweetpotato roots, microarray analysis was used to investigate genes differentially expressed between White Jewel and Jewel storage roots. β-carotene content calculated for Jewel and White Jewel were 20.66 mg/100 g fresh weight (FW) and 1.68 mg/100 g FW, respectively. Isopentenyl diphosphate isomerase was down-regulated in White Jewel, but three other genes in the β-carotene biosynthetic pathway were not differentially expressed. Several genes associated with chloroplasts were differentially expressed, indicating probable differences in chromoplast development of White Jewel and Jewel. Sweet potato virus disease (SPVD) is caused by the co-infection of plants with a potyvirus, Sweet potato feathery mottle virus (SPFMV), and a crinivirus, Sweet potato chlorotic stunt virus (SPCSV). Expression analysis revealed that the number of differentially expressed genes in plants infected with SPFMV alone and SPCSV alone compared to virus-tested plants was only three and 14, respectively. In contrast, more than 200 genes from various functional categories were differentially expressed between virus-tested and SPVD-affected plants. Microarray analysis has proved to be a useful tool to study important aspects of sweetpotato physiology and production.

Sweetpotato [Ipoma batatas (L.) Lam.] is a major subsistence crop in Sub-Saharan Africa, where iron and zinc deficiency in humans is an important health problem. A sweetpotato cultivar suited for subsistence farming, with high iron and zinc concentration, would be important in alleviating these deficiencies. The main objective of this research was to identify the extent of genetic variability of iron and zinc concentration in sweetpotato germplasm. An important subcomponent of this research was to determine the heritability of iron and zinc in sweetpotato. Protocol development studies were also conducted to aid in determining proper sampling technique. The results of the protocol development study indicated there was a significant replication effect between plot replicates but that no significant variation existed among roots from a plant, among plants from a given replicate plot, or among different root zones. In general, most of the genetic variability present was attributable to the difference in genotype. Therefore, one root from each replicate is sufficient for determining iron and zinc concentration in sweetpotato. A three-fold difference between high- and low-yielding cultivars for iron and zinc for ~80 cultivars was observed. The cultivars with the highest iron concentration were 'Kyukei No. 63' and 'Pata de Oso', both with ~7 ppm iron, fwb, from Japan and Peru, respectively. This compares with cultivars 'Pung-mi' and 'Chuquimanco' from Korea and Peru, respectively, both with ~3 ppm iron, fwb. These results suggest that sweetpotato with the highest levels of iron and zinc could provide about 30% and 15% of the daily dietary intact of these micronutrients, respectively. This is based on daily consumption of one 300-gram root. Iron and zinc in sweetpotato is highly available to humans given low phytic acid and high ascorbic acid concentration in orange flesh varieties. The heritability study showed high broad-sense heritability for iron (H² = 0.74), zinc (H² = 0.82), and dry matter concentration (H² = 0.93) among half-sib families. These results and those which showed a positive correlation between iron and zinc concentration suggest that traditional breeding strategies like mass selection could improve the nutritional value of sweetpotato.

Liriopogons are evergreen perennials with a confusing taxonomy. New cultivars are being rapidly selected and named. The landscape industry uses them extensively and they are being planted in improper sites. Morphological studies were done at Louisiana State University in Baton Rouge, Louisiana to identify cultivars by comparing plants to botanical keys. Cultural studies were done at Burden Station in Baton Rouge, Louisiana by comparing cultivars in sun and 63% shade, and by greenhouse fertilization experiments, and pruning experiments. Plants were harvested, studied, dried and mounted in the Louisiana State University Herbarium as permanent record. Of the 19 cultivars of Liriope and Ophiopogon studied, there were two genera and eight species identified. These were studied for flower morphology on dissected flowers under microscope. Aztec grass, which had been labeled Ophiopogon jaburan was discovered to be Ophiopogon intermedius. Liriope muscari 'Big Blue' is L. muscari but some plantings in landscapes are L. exiliflora. The cultivar 'Samantha' has erroneously been classified L. muscari but cf. to L. exiliflora, according to the rhizomatous root system and spaces between flowers. 'Evergreen Giant' and Supergreen Giant were called cultivars of Liriope muscari and they are morphologically Liriope gigantea 'Evergreen Giant' and 'Merton Jacobs' Supergreen Giant respectively. A three-year study at Burden Center with 19 cultivars, sun and 63% shade treatment and six replications showed the top sun performing cultivar to be Liriope gigantea 'Merton Jacobs' Supergreen Giant. The second was Liriope muscari 'Big Blue.' Liriope muscari 'Monroe White' and Ophiopogon japonicus 'Silver Mist' were the two low sun performers. The top shade performers were O. japonicus and O. japonicus 'Nana.' The low sun performers were Liriope muscari 'Densiflora' and Liriope gigantea 'Evergreen Giant.' Bib production benefited by 20% pruning in Ophiopogon intermedius but did not have significant effects on any other cultivar. Plant height, quality, N and P were the most influenced variables for all combinations of liquid fertilization + controlled release and liquid fertilizer alone over any of the controlled release rates of fertilization.

The sunflower is one of the most important specialty cut flowers produced. Sunflowers have a short and variable postharvest longevity that is dependent upon cultivar. Research in postharvest physiology of cut flowers indicates that calcium (Ca) may be involved in delaying flower senescence by postponing cell membrane degradation. Cut flowers with intact cell membrane structure and function maintain their water balance and last longer. This study was developed to determine the effects of Ca supplementation on longevity of fresh cut sunflowers. The cultivar Superior Sunset was used in this study; the sources of Ca were Ca(NO3)2, CaCl2 or a chelated Ca at 125 (low), 250 (medium), or 500 (high) mg/l amounts of Ca. The chelate minus Ca and sodium nitrate (NaNO3) were used as control treatments. Untreated flowers were included in all the experiments; means and standard errors were calculated for comparison with treatments. Ca was applied prior to harvest as a foliar spray or a weekly drench. Results indicated that the Ca treatments did not increase postharvest longevity of sunflower when treated preharvest; however, there was an increase in Ca concentration of stem tissue content compared to the untreated plants. Postharvest application of Ca chelate supplied as a 2-h pulse increased postharvest longevity of sunflower by up to 2 d compared to untreated flowers. Sunflowers treated with Ca also had a greater increase in fresh weight after 8 d in postharvest and improved water retention. Sunflowers treated with Ca had a greater concentration of the cation compared to the untreated flowers.

Four temperatures were tested to determine the optimum temperature for seed germination of Paspalum vaginatum 'Seaspray' seed. Results indicated that Paspalum vaginatum germination percentage was greatest at 30°C. Three seed enhancement treatments were applied to Paspalum vaginatum seed to determine improvements in germination percentage and MTG of the seed. Potassium nitrate, GA, and soaking seed in distilled water yielded greater germination percentages than the dry control. Seeds subjected to enhancement treatments had significantly faster MTG rates than the dry control seeds. Seeds also had higher germination percentage with exposure to light when compared to seeds that germinated in conditions not exposed to light. MTG was not significantly different. Paspalum vaginatum seed was allowed to germinate at 0, 14, 28, and 42 days, before a simulated rainfall. Mean seed loss was significantly greater at 0, 14 and 28d before the rainfall, then 42d before the rainfall was significantly lowest in soil loss. Mean growth of seedlings after the rain simulation was highest at 0 and 14d planted before rainfall. Paspalum vaginatum was compared with Cynodon dactylon and Eragrostis curvula as a possible turfgrass selection for usage as a vegetative cap over a brine landfarm. Grasses were planted in depths of 0, 5.08, 10.16, and 15.24 cm of river silt over the brine field. Results indicated that Paspalum vaginatum assimilated significantly greater quantities of Na than Cynodon dactylon, and Eragrostis curvula. Chloride was the only analyte that was measured in significantly greater amounts when compared by species and depth. Paspalum vaginatum growing in 5.08 cm contained highest concentrations of chloride in the plant tissue, indicating that Paspalum vaginatum would be a potential brine remediator species. The combined results from the four projects indicate that Paspalum vaginatum 'Seaspray' is a suitable turfgrass selection for the Gulf Coast states, especially in areas with saline soils.

Virus diseases are a major constraint to sweetpotato production in East Africa. The most important is the Sweet potato virus disease (SPVD), a result of co-infection of Sweet potato chlorotic stunt virus (SPCSV) and Sweet potato feathery mottle virus (SPFMV). Studies were done on different aspects of resistance to SPVD, and to determine the presence of Sweet potato virus G (SPVG), Sweet potato virus 2 (SPV2), and Sweet potato leaf curl virus (SPLCV), viruses that have not been reported infecting sweetpotato in Kenya. None of the samples reacted to antisera for either SPVG or SPV-2. SPLCV was detected infecting sweetpotato in Kenya for the first time. Some sweetpotato genotypes have irregular distribution or low virus titers, or recover from SPVD. The possibility of using this resistance to obtain virus free cuttings from field-grown sweetpotato vines for propagation was studied. Vines were cut into three pieces (15 cm, 15-30 cm, and >30 cm from the apex) and tested for SPCSV, SPFMV and Sweet potato mild mottle virus (SPMMV), the most common viruses in Kenyan fields. The viruses were equally present in all sections of infected vines and no section was any more likely to be virus free. Accumulation patterns of SPCSV and SPFMV in mixed infections were compared in SPVD-susceptible cultivars, Beauregard and Namaswakhe, and resistant cultivars, Naspot I and Mar Ooko. Virus titers were estimated using real-time quantitative PCR. Resistance in Naspot I and Mar Ooko was associated with reduced SPCSV and SPFMV multiplication, respectively. Titers of both viruses increase to certain thresholds after which symptoms appear, indicating that both viruses are important in SPVD development. To determine if SPVD resistant genotypes could be identified using molecular markers, sweetpotato genotypes were selected and classified as resistant or susceptible and amplified fragment length polymorphism (AFLP) marker profiles used in association studies. Analysis of molecular variance found significant (P<0.002) differences between the two groups. Discriminant and logistic regression analysis were used to select informative markers, and to develop models to classify the two groups. Four markers, which gave 94% correct classification of a test population, were selected by both statistical methods.