Agriculture and Plant Science.

Chair: Juan L. Silva, Mississippi State University 

Vice-chair: O.P. Vadhwa, Alcorn State University 

THURSDAY MORNING

Caribbean

9:15 Introduction

9:30 HYPERSPECTRAL REMOTE SENSING OF INVASIVE WETLAND PLANTS

Tami Wells* and Gregory A. Carter, University of Southern Mississippi, Hattiesburg, MS 39406, and Gulf Coast Geospatial Center, Ocean Springs, MS 39564

Hyperspectral image data were used as a baseline for mapping wetland plant species with emphasis on the detection of invasive plants in Northern Mobile Bay. Reflectances of wetland plant species were acquired from imagery collected by the airborne ITD VNIR 10E Hyperspectral Sensor developed by the Institute for Technology Development at Stennis Space Center. Image data collected through the visible to near infrared spectrum (350-1050 nm wavelengths) were evaluated to determine characteristic spectral signatures of indigenous and non-indigenous plant species important to the structure and dynamics of the estuary. Spectral signatures were significant in delineating the diversity among native wetland plants and detecting invasive species. Results indicate that hyperspectral imagery can be extremely effective in detecting and monitoring invasive plant populations and overall plant biodiversity in a critical coastal ecosystem.

9:45 SENSITIVITY ANALYSIS OF HYDROLOGIC MODEL PARAMETERS FOR THE ST. LOUIS BAY WATERSHED

Z. Liu*, W.L. Kingery, V.J. Alarcon, and D.H. Huddleston, Mississippi State University, Mississippi State, MS 39762

The application of physically based models such as Hydrologic Simulation Program-Fortran (HSPF) to real watersheds requires a larger number of parameters to be estimated for the purposes of model calibration. Sensitivity analysis is a very effective method to screen for the more sensitive parameters in order to provide guidelines for more efficient calibration efforts. Sensitivity analysis was employed to study four HSPF model output variables: streamflow, surface runoff, interflow outflow, and active groundwater outflow. Fourteen HSPF hydrologic input parameters have been examined under five different simulation scenarios for the St. Louis Bay watershed. For each of the parameters, a normalized sensitivity coefficient has been calculated to determine the degree of sensitivity of the output variables to it. Additionally, the interaction between input parameters was evaluated. Through our research, the critically sensitive parameters for each of the four model outflow variables used in the simulation of the Bay St. Louis watershed hydrology.

10:00 BERMUDAGRASS SEEDLING GROWTH IN DRASTICALLY ALTERED AND AMELIORATED SOIL

R.M. Stout*, W.L. Kingery, M.E. Zappi, and J. Harden, Mississippi State University, Mississippi State, MS 39762

Fenton's reagent, which contains hydrogen peroxide and an iron catalyst, is used in remediation of soils and waste-waters contaminated with organic compounds. Because Fenton is such a powerful oxidant, there is a concern that soils remediated using this treatment are rendered infertile. The objective of our work was to evaluate bermudagrass (Cynodon dactylon) germination and seedling vigor as influenced by various ameliorants on Fenton-treated soils. We treated an uncontaminated Alfisol with Fenton's Reagent and incorporated different soil amendments into the pots. The soil ameliorants include: (1) Hu-More[TM] with alfalfa, (2) mycorrhizal spores, (3) a commercially available concoction of microorganisms (Equity[TM]), (4) Equity plus humates, and (5) earthworms. Other treatments included various combinations of these five. Bermudagrass seeds were planted in pots containing ameliorated soils and kept watered in a greenhouse for two weeks. Data collected included: days to emergence, leaf blade length and width, internode length, root and shoot fresh weight, dry weight at harvest, soil pH, extractable soil nutrients and other fertility-related variables. Soil treated with Fenton's requires amelioration in order to make it fertile and capable of supporting plant growth. Treatments with a combination of ameliorants 1, 2, 4, and 5 produced the highest soil pH with a mean of 7.7; the natural soil pH was 5.2 and the Fenton-treated pH was 4.4. Ameliorant 2 had the highest shoot and root dry weight.

10:15 EFFECT OF PLANT SPACING ON THE GROWTH AND QUALITY OF LEMONGRASS (CYMBO-POGON CURATES)

Stephen Asumeng (1)*, Patrick E. Igbokwe (1), Dovi Alipoe (1), Liang Huam (1), Magid Dagher (1), Charles Burandt (2), and Larry Russell (1), (1) Alcorn State University, Alcorn State, MS 39096, and (2) University of Mississippi, Oxford, MS 38677

Field experiments were used to determine the effect of three plant spacings (30.0, 45.0, and 60.0 cm) on lemongrass (Cymbopogon curates) growth potential and quality. These studies were conducted on a Memphis silt loam soil at the Alcorn Experiment Station: Field plot design was a randomized complete block (RCB) with four replications of each spacing (treatment). Plant growth was based on the above- and below-ground growth parameter productions, whereas, quality was based on the leaf-essential oil compositions. Mean values for plant width, and number of tillers per plant were significantly highest (1.22 m and 35.75 tillers, respectively) at 45.0 cm spacing, and lowest (0.91 m and 27.75 tillers, respectively) at 30.0 cm spacing. Mean weights for the aboveground plant biomass per row was significantly highest (30.5 kg) at 30.0 cm spacing, but was not different from 27.3 kg reported at 45.0 cm spacing. Root weight per plant was significantly highest (0.61 kg) at 60.0 cm, compared to 0.43 kg reported at 30.0 spacing. Percent essential oils (citral, geraniol, geranial, and neral) were generally highest at 45.0 cm spacing and lowest at 60.0 cm spacing.

10:30 Break

10:45 THE USE AND RESULTS OF A STRUCTURED COHERENT ELECTROMAGNETIC FIELD ON PRODUCTION PARAMETERS WHEN APPLIED IN COMMERCIAL EGG- LAYING CHICKENS

Robert W. Keirs* and E. David Peebles, Mississippi State University, Mississippi State, MS 39762

Electromagnetic field (EM field) units were equally spaced when installed in typical commercial layer houses that were located in the same geographical area and under the same management program. The same breed of egg layers was utilized in two different houses during the production phases for a total of five separate flocks housed chronologically from August 23, 1997, through October 6, 2003. Number of eggs laid per each hen housed (E/HH) and hen mortality per day (HDM) were monitored up to 60 weeks of bird age. The E/HH and HDM of the birds subjected to EM fields were compared to respective commercial standards that represent a reasonable genetic potential under optimal conditions [referred to as 'Breeder Goals' (BG)]. In four flocks subjected to EM fields, E/HH was 1.58, 7.09, 6.61, and 7.66% higher than BG to 60 weeks of age. For the fifth flock, E/HH was increased by 1.43% over BG to 56 weeks of age. The HDM of the first four flocks subjected to EM fields was 36.57, 51.26, 30.13, and 44.10% lower than BG to 60 weeks of age. For the fifth flock, HDM was decreased by 24.57 under BG to 56 weeks of age. Overall, these data suggest that the influence and utilization of EM fields in intensified animal agriculture should be considered and studied.

11:00 QUALITY RETENTION OF SELECTED FRESH-CUT VEGETABLES AS AFFECTED BY CUTTING METHOD

Lorena Albuja*, Taejo Kim, and Juan L. Silva, Mississippi State University, Mississippi State, MS 39762

Fresh-cut vegetables have become a rapid-growing segment of the US fresh produce industry. These products have the attributes of convenience and fresh-like quality. While conventional food processing methods extend shelf-life of vegetables, minimal processing renders them highly perishable. Minimal processing can be performed either manually with knives or mechanically with commercial slicing machines. The effect of manual and machine processing on quality retention of selected vegetables, simulating a foodservice process, were evaluated. Machine cut processing significantly reduced overall quality of tomatoes. In the case of mushrooms, lettuce, cabbage and cauliflower, hand cut samples quality was higher than machine cut samples, but only during the first days of storage; whereas in the case of onions, celery and carrots, the type of cutting did not have any effects. Microbial load of hand cut was lower than for machine cut in cauliflower. Yeast and mold counts differed for hand and machine cut cauliflower, cabbage and celery. Hence, the type of cutting affects quality retention depending on the product, apparently due to differences in the amount of damage incurred. In general, acceptable quality of hand and machine cut products can be retained for three days in a foodservice environment. It is recommended that tomatoes be processed with sharp stainless steel knives to minimize tissue disruption.

11:15 GASEOUS STORAGE EFFECT ON FRUIT QUALITY AND SHELF LIFE OF BLUEBERRIES

Angsana Tokitkla*, Juan L. Silva, Taejo Kim, and Frank B. Matta, Mississippi State University, Mississippi State, MS 39762

In recent years, the detection of outbreaks of food-borne illnesses has increased. The main food-borne pathogen in fruits and vegetables are E. coli O157:H7 and Salmonella. There are many methods used to reduce these on fruits. Wetting the blueberries in an aqueous solution result in higher fruit decay and cause extra handling and expense of drying them. Therefore, this experiment was set up to examine the effectiveness of ozone, S[O.sub.2] and C[O.sub.2] (in gas form) in extending the shelf-life and quality of rabbiteye blueberries (Vaccinium ashei). Fruits were placed in clamshells. The packages were loaded in hermetically sealed containers, and fumigated every sampling time with ozone, 193 ppm S[O.sub.2], 20% C[O.sub.2], or normal air. Boxes with fruit were stored at 2 [degrees]C and sampled periodically for 40 days. Fruit decay was higher for berries stored in the control treatment than it was for berries stored in ozone, S[O.sub.2] and C[O.sub.2]. Weight loss did not differ between treatments, while acidity decreased especially in S[O.sub.2] berries and firmness higher in ozonated berries. Panelists preferred berries stored under ozone or C[O.sub.2] after 41 days. Ozone and S[O.sub.2] can therefore be considered as gases used in MAP to extend the shelf life and inhibit the pathogenic bacteria for blueberries.

11:30 INFLUENCE OF SURFACE TREATMENTS AND STORAGE TEMPERATURE ON SHELF LIFE AND QUALITY OF RABBITEYE BLUEBERRIES

Jelena Stojanovic*, Juan L. Silva, Chonthida Kaewplang, and Youkai Lu, Mississippi State University, MS 39762

Mississippi ranks seventh among blueberry producing states in the nation. Most of the 4 million tons produced in 2001 were marketed as a fresh fruit. This kind of marketing imposes a shelf life issue, and with that an economic problem, taking into account the perishable nature of the fresh blueberries. The objective of this study was to evaluate different treatments and storage temperatures on shelf-life and quality of rabbiteye (Vaccinium ashei) blueberries. Fresh picked blueberries were packed untreated (control) or treated with 100ppm chlorine solution and with Tsunami (40 ppm peroxyacetic acid) for 30s, air dried and placed in plastic clamshells. Samples were stored at 2-3 [degrees]C (RF) and part at the room temperature, RT (21 [degrees]C), and evaluated every five days for up to 40 days. Samples were analyzed for texture, weight loss, color, total anthocyanins, total phenolics, yeast and molds, aerobic plate and psychotropic plate counts. Color and firmness changes were more prominent on RT berries. After 25 days, RT berries lost 24-36% of their total weight, while RF berries lost 10-15% of their weight after day 40. Changes in anthocyanins and phenolics were evident after 10 days, regardless of storage temperature. A 2-log increase in microbial counts was recorded for RT berries regardless of treatment after 5 days. Chlorine solution was most efficient in reducing microbial counts on berries. Refrigeration of blueberries seems to be more important than pretreatment in extending shelf-life and maintaining quality of blueberries.

THURSDAY AFTERNOON

Caribbean

1:00 BEST INCUBATION TEMPERATURE FOR PREDICITING MICROBIAL LOAD AND SPOILAGE OF CATFISH

Youkai Lu*, Juan L. Silva, and Taejo Kim, Mississippi State University, Mississippi State, MS 39762

Aerobic plate counts (APC), incubated at 35[degrees]C, and psychrotrophic plate counts (PPC), incubated at 20 [degrees]C, are commonly used as an index to reflect the microbiological quality and predict shelf-life of farm-raised channel catfish (Ictalurus punctatus) during processing and storage. The objectives were to compare the changes in APC and PPC and their correlation with overall sensory scores, of refrigerated catfish fillets stored at 0 [degrees]C and 4 [degrees]C. The PPC and APC on fillets stored at 0 [degrees]C had about four and six days lag phase, respectively. The PPC on fillets stored at 4 [degrees]C did not show any lag phase and grew rapidly; while APC of fillets stored at 0 [degrees]C had two days of lag phase. The APC were always over 1 log lower than PPC at each storage period. But the difference was higher from fillets stored at 0 [degrees]C than from fillets stored at 4 [degrees]C. Thus, APC incubated at 35 [degrees]C are not a good procedure to reflect microbiological quality of catfish. But PPC incubated at 20 [degrees]C could be a better indicator of catfish shelf-life, reflecting microbiological quality of catfish during refrigerated storage.

1:15 THE EFFECT OF OZONE AND CARBON DIOXIDE MODIFIED ATMOSPHERE STORAGE ON PATHOGENS OF CATFISH FILLETS

Somsamorn Gawborisut* and Juan L. Silva, Mississippi State University, Mississippi State, MS 39762

Catfish growers in the 13 producing states had sales of 385 million dollars during 2001. Mississippi produces about 60% of the catfish in the United Sates. Overall sales of catfish products were down in 2001, but sales of fresh catfish products rose 3.5% in 2001. Most of the increase in sales of the fresh catfish products was due to a 9.5% increase in fresh catfish fillets. The U.S. FDA has not approved most seafood products be packaged and distributed under modified atmosphere package (reduced oxygen), unless the temperature can be controlled throughout their life. Modified atmosphere storage (MAS), a supplemental technique to refrigeration, may be a feasible alternative to extend shelf life of fresh catfish fillets. Growth of Listeria monocytogenes and Salmonella typhimurium as affected by atmospheric conditions (100% carbon dioxide, ozone atmosphere, and air) and storage time were investigated. Growths of the pathogens (inoculum size of [10.sup.4] cfu/g of catfish fillet) were slightly reduced by ozone and 100% carbon dioxide after four days storage. Even though ozone is a powerful oxidizing agent and carbon dioxide can suppress several genera of bacteria (bacteriostatic), rough surface and composition of the fillets may protect the bacteria from contact with the gases. Additional methods such as irradiation or chemical treatments may be required to reduce initial load in catfish fillets and increase MAS effectiveness.

1:30 Divisional Poster Session

BIOACCUMULATION OF CADMIUM IN WHEAT PLANTS

P. Kumar, K.L. Shumaker, and M. Zaman*, Mississippi School for Mathematics and Science, Columbus, MS 39701; Jackson State University, Jackson, MS 39217; and Alcorn State University, Alcorn State, MS 39096

The tolerance of wheat plant (Triticum sativum) to soil cadmium (Cd) and bioaccumulation of Cd in plant tissue were evaluated. Plants were grown under color corrected lights in soils containing 0, 500, 1000, and 2000 ppm Cd. Plants were harvested on day 30 of the experiment and dried plant samples were acid digested for tissue Cd analysis. Tissue Cd accumulation was performed using an atomic absorption spectrophotometer. Data were analyzed for plant biomass, growth inhibition, and Cd accumulation in plant tissue. Results indicated that wheat plants were able to tolerate high Cd concentration in soil, and plant biomass production, growth inhibition, and bioaccumulation of Cd in plant tissues were dose related. Plant Cd accumulations were 59% and 83% higher than the 1000 ppm and 2000 ppm Cd concentrations in soils respectively. Overall data indicated that T. sativum is a Cd hyperaccumulator and can be used for phytoremediation of Cd contaminated soil.

SOIL MICROBIAL ACTIVITY AND POPULATION RESPONSES TO HEAVY METAL AND SHELTIE AMENDMENTS

M.T. Begonia*, G.B. Begonia, G. Miller, D. Gilliard, and C. Young, Jackson State University, Jackson, MS 39217

Little is known about in situ microbial community responses to heavy metal stress. Such study is necessary before remediation of heavy metals from contaminated soils can be effectively pursued. The objectives of this study were to quantify soil phosphatase activity and microbial populations of a heavy metal- and chelate-amended soil that had been previously cropped with wheat for six weeks. Results revealed that phosphatase activity generally decreased with increasing level of soilapplied lead (Pb) and cadmium (Cd). This decrease in microbial activity was more pronounced in the presence of chelates. Results also indicated that bacteria were not inhibited by Pb since soils treated with the highest Pb level had the highest bacterial population. Cd was extremely inhibitory to bacteria as exhibited by the significantly low bacterial numbers at all Cd treatments compared to the control. Fungi were more sensitive to Pb as shown by the significant decrease in fungal population especially at the highest Pb treatment. EDTA alleviated the toxic effect of the lowest Pb treatment on fungal population. Cd did not inhibit fungal proliferation since fungal population increased with increasing level of applied Cd. The resistance of soil bacteria and fungi to soilapplied Pb and Cd indicates that these microorganisms may have resistance mechanisms to deal with metal toxicity.

EFFECTS OF CHELATE APPLICATION TIME ON THE PHYTOEXTRACTION OF LEAD-CONTAMINATED SOILS

G.B. Begonia*, M.T. Begonia, and G. Miller*, Jackson State University, Jackson, MS 39217

Chelate-assisted phytoextraction has been proposed as an effective tool for the phytoremediation of heavy metal-contaminated soils. However, chelate-enhanced metal leaching could also lead to secondary pollution. Therefore, greenhouse studies were conducted to determine the effects of chelate application time on the phytoextraction of lead (Pb) by a high biomass crop. Two wheat (Triticum aestivum L. cv. TAM-109) seeds were sown in each 150 mL tube containing a growth medium (sieved soil and peat, 2:1, v:v) that had been spiked with either 1,000 or 2,000 mg Pb/kg dry medium. Chelates were also applied to the Pb-spiked growth medium either before planting (i.e., early-season application) or at 42 days after planting (i.e., mid-season application). After six weeks of growth, plants were harvested at 0, 3, and 7 days after mid-season chelate application corresponding to 42, 45, and 49 days after planting (DAP), respectively. Results showed that Pb translocation to the shoot was greatest at 3 days after mid-season application (45 DAP) compared to an early season application. These results imply that chelates can be applied when plants have attained maximum biomass then harvested a few days later thereby avoiding the possibility of a chelate-induced metal movement into the ground water.

ON-FARM ASSESSMENT OF THE EFFECTS OF RICE WATER WEEVIL CONTROL ON YIELD FACTORS OF RICE

B.C. Owens (1)*, W.L. Kingery (1), T.W. Walker (2), and J.E. Street (2), (1) Mississippi State University, Mississippi State, MS 39762, and (2) Delta Research and Extension Center, Stoneville, MS 38776

On-farm experimentation involves a much larger matrix of interacting factors than does research under highly controlled conditions in the greenhouse or on agricultural research stations. For this reason testing hypotheses related to agronomic practices under actual production environments is critical to their appropriate evaluation. Control of rice water weevil (Lissorhoptrus oryzophilus), which is the most destructive insect pest of rice (Oryza sativa) in the U. S., was evaluated on fields located in Washington, County. Cocodrie variety seeds that were either treated with 6.2 FS Fipronil or left untreated were sown in separate areas in each of three fields. In four randomly selected sites within each treatment, data were collected weekly on pest activities (e.g., rice water weevil counts, weevil feeding, and plant damage) and agronomic traits (plant height, joint movement, tillering, boot stage, etc.). In addition, careful records of crop management were made. Despite complex interactions over time and space of pests, climate, soils, and management, careful mapping of rice yield factors under a scientifically sound protocol allows for the development of reliable conclusions regarding cultural practices.

EFFECT OF FERTILIZATION APPLICATION ON PRODUCTION AND LEAF MICRONUTRIENT ELEMENTAL CONTENT OF MALABAR SPINACH (BASELLA ALBA L.)

O.P. Vadhwa (1)*, D.A. Marshall (2), and J.M. Spiers (2), (1) Alcorn State University, Lorman, MS 39096, and (2) USDA-ARS Small Farm Fruits Research Station, Poplarville, MS 39470

The effects of four fertilizer treatments on yield, plant growth parameters, and leaf elemental micronutrient content of 'Malabar' spinach (Basella alba L.) were evaluated in a Ruston fine sandy loam soil (fine-loamy, siliceous, thermic Typic Paleudult) at the USDA Small Fruits Research Station in Poplarville, MS. Fertilizer (13-6-11) treatments consisted of (1) 112 kg/ha applied twice during the season (June and August) for a total of 224 kg/ha, (2) 112 kg/ha applied four times during the season (June, July, August, September) for a total of 448 kg/ha, (3) 224 kg/ha applied twice for a total of 448 kg/ha, and (4) 224 kg/ha applied four times for a total of 896 kg/ha. Plant growth was positively correlated with total N applied regardless of application timing. Leaf yield followed the same pattern as total plant growth, except frequent N applications was as important as total applied N. Leaf size was smallest with the 224 kg/ha per year N fertilization rate. Nitrogen rates of 448 to 896 kg/ha per year did not result in different leaf size regardless of the number of applications. Leaf Fe concentrations were decreased as levels of N fertilizations were increased. Similar trend was also observed for B concentration in leaves. N fertilization rates had no effect on leaf concentration of Mn, Zn, and Cu.

CONSUMER RESPONSE TO VALUE ADDED FISH MINCE PRODUCTS

Susan DeBlanc* and Linda S. Andrews, Mississippi State University, Mississippi State, MS 39762

Two species of underutilized Gulf of Mexico fish were analyzed for their suitability and consumer acceptability for value added seafood products. Chub mackerel (Scomber japonicus) and hard head catfish (Arius felis) minces were prepared by washing raw mince at varying pH. Previous results showed that Chub mackerel mince is high in protein and low in fat content and has potential for production of raw surimi or mince-based value added products. Fish mince cakes and fish meatballs were prepared and served to consumer panelist for sensory survey. Consumer volunteers were recruited from local "festivals" in South Mississippi. Consumer acceptability of fish mince cakes has been very favorable (7.4-7.8 acceptability for mackerel and catfish, respectively).

Divisional Lecture

2:30 PROTEOMICS: NOT JUST ANOTHER OMICS

H. Alan Wood, Mississippi State University, Mississippi State, MS 39762

Proteomics has emerged as one of the most powerful tools in the biotechnologies. A proteome is the complement of proteins present in an organism, organ, cell, or organelle at a specific point in time under a specific set of conditions. The term proteomics has come to convey differences in proteomes. These differences can result from cell cycle state, nutrient and growth conditions, pathological disorders, environmental responses, etc., etc. Accordingly, proteomics has become a valuable tool in medical, agricultural and environmental studies. The Life Sciences and Biotechnology Institute at MSU has established a proteomics core facility. It is available to all faculty and students of Mississippi universities and colleges as well as Mississippi companies. The nature and utility of the equipment will be discussed along with the various proteomic technologies that can be used to solve your biological problem quickly and easily.

3:00 Divisional Business Meeting