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Agriculture and Plant Science.

Chair: O.P. Vadhwa, Alcorn State University

Vice-chair: David Kingery, Mississippi State University

THURSDAY MORNING

Classroom A

8:30 RESPONSE OF SOIL MICROBIAL COMMUNITIES AND PROCESSES TO WINTER FLOODING

Melanie Patterson (1*), Robert M. Zablotowicz (1), Mark A. Weaver (1), Clifford H. Koger (1), and Joseph Wahome (2), (1) USDAARS, Stoneville, MS 38776 and (2) Mississippi Valley State University, Itta Bena, MS 3894

Flooding of rice fields following harvest has potential to enhance rice straw degradation, control weeds, provide waterfowl habitat, and reduce soil loss. This study assessed the effects of winter flooding of a rice field on soil microbial communities and processes. Flooded plots maintained 10 cm of standing water from October 2003 to March 2004 and were compared to non-flooded plots receiving only rainfall. Soils (0 to 2.5 cm) were sampled monthly and were analyzed for extractable anions, total carbon, and nitrogen. Biological parameters evaluated included two soil enzyme assays (fluorescein diacetate hydrolysis (FDA) and triphenyl tetrazolium chloride dehydrogenase) and soil community analysis by fatty acid methyl ester (FAME). Following flooding, soil redox potential in flooded plots was below -100 mV and greater than 100 mV in non-flooded plots. Nitrate was rapidly depleted in flooded soils with subsequent accumulation of acetic acid, indicating fermentative metabolism of organic substrates. Flooded soil dehydrogenase activity was 51 to 330% greater (p > 0.01) than non-flooded soil, while FDA activity was greater in flooded soil in only three of seven sampling dates. Microbial community structure (FAME analysis) indicated a significant shift in response to flooding, e.g., decreased fungal and gramnegative biomarkers, and increased gram-positive FAMEs. In April only 30% of the straw in the non-flooded plots was degraded compared to 60% in flooded plots. These data indicate that winter flooding rapidly alters microbial populations and activity while enhancing straw degradation. The role of anaerobic microbial processes accelerating straw degradation is being further investigated.

8:45 A WATER QUALITY SURVEY OF THE UPPER PEARL WATERSHED IN EAST-CENTRAL MISSISSIPPI

Mary Love Tagert*, Joseph H. Massey, David R. Shaw, and M. Cade Smith, Mississippi State University, Mississippi State, MS 39762

To assess the current level of impairment by pesticides and sediment in the Upper Pearl River Basin (UPRB), grab samples were collected for pesticide analysis at seven United States Geological Survey (USGS) gauged locations within the watershed. Depth-integrated water samples were also collected at three sites to be analyzed for total dissolved solids (TDS). Samples for pesticide analysis were collected weekly from May through August 2002, and monthly thereafter through May 2003. Samples for TDS analysis were collected from September 2001 through January 2003. Pesticide samples were extracted via Solid Phase Extraction (SPE), and analyzed for fifteen different pesticides using GC-MSD: triclopyr, 2,4-D, tebuthiuron, simazine, atrazine, metribuzin, alachlor, metolachlor, cyanazine, norflurazon, hexazinone, pendimethalin, DDT insecticide degradation product p,p'-DDE, diuron, and fluometuron. TDS samples were analyzed using a gravimetric method. Hexazinone was the most frequently detected compound, with 171 out of a possible 181 detections, followed by metolachlor, tebuthiuron, and atrazine. Metribuzin was the least detected compound, with 11 detections out of a potential 181 detections. TDS concentrations were highest at the Carthage site, which drains the largest area of the three sites sampled. Most concentrations were below Environmental Protection Agency (EPA) standards for pesticides and TDS in drinking water, and most were below current toxicity thresholds set for freshwater aquatic organisms.

9:00 RELATIONSHIPS BETWEEN PHOSPHORUS CONCENTRATIONS AND SOIL PROPERTIES IN AN AGRICULTURAL WATERSHED

Rachel Stout (1*), W.L. Kingery (1), M.S. Cox (1), P.D. Gerard (1), M. Lilly (2), and S. Depew (2), (1) Mississippi State University, Mississippi State, MS 39762 and (2) USDA-NRCS, Jackson, MS 39269

Watershed characterization is central to the formulation of Total Maximum Daily Load (TMDL) parameters and simulation model parameters. The objective of this study was to combine Soil Survey Geographic Database (SSURGO) data with field data to determine correlations between soil phosphorus and soil properties such as clay percentages, slope, and permeability. Soil samples were collected along transects and across grids over approximately 600 acres at the Pontotoc Ridge/Flatwoods Branch Experiment Station. Detailed profile descriptions and basic soil characterizations were made for each transect core. Grid samples were collected at 0 to 6-inch depth and analyzed for weak acid-extractable, base-extractable, and total phosphorus (P). Acid-extractable P concentrations ranged from 0.7 to 985 mg P/kg soil, and from 1 to 289 mg P/kg soil for base-extractable P. Simple regression was used to correlate soil properties to P levels. The influence of land use/land cover and management history will also be presented.

9:15 TESTING THE EFFICACY OF NATURAL-BASED FUNGICIDES IN PLANTA

Maritza Abril (1*), Kenneth J. Curry (1), David E. Wedge (2), and Barbara J. Smith (3), (1) University of Southern Mississippi, Hattiesburg, MS 39406; (2) Natural Products Utilization Research Unit; USDA-ARS, University, MS 38677; and (3) USDA-ARS, Small Fruits Research Station, Poplarville, MS 39470

Detached leaf trials were conducted challenging Colletotrichum fragariae isolate CF-75 with the experimental fungicides sampangine and CAY-1 and the commercial fungicide azoxystrobin all at concentrations of 625, 1250, and 2500 ppm. Leaves collected from strawberry (cv. Chandler) were maintained by inserting the petiole into a small test tube containing water and inoculated either 24 hr before (pre) or 24 hr after (post) application of test compounds. Leaves were incubated at 100% RH for 48 hrs and evaluated for disease development 5 days after inoculation. The data were analyzed statistically using Statistical Analysis Systems (SAS) software. The pre-inoculation experiments generally did not stop disease symptoms from appearing. In the post inoculation treatments, Sampagine and azoxystrobin were effective at all concentrations, and CAY-1 was effective at 1250 and 2500 ppm only. Screening procedures are commonly assessed at the macroscopic or whole plant level while frequently neglecting the microscopic or (whole) fungal level. We developed a leaf-clearing technique to establish reproducible germination conditions. Most treatments in the pre-inoculation experiments showed large numbers of appressoria on the leaf surfaces as expected, since the fungi germinated before the fungicides were applied. Most of the post-inoculation treatments showed reduced numbers of germinated fungal spores. These three fungicides apparently stop fungal germination, but would not be affective as a curative fungicide against a fungus that had already invaded its host plant.

9:30 ASSESSMENT OF THE SENSITIVITY OF NATURAL-BASED AND COMMERCIAL FUNGICIDES AGAINST TARGETED PHYTOPATHOGENIC FUNGI

Maritza Abril (1*), David E. Wedge (2), and Kenneth J. Curry (1), (1) University of Southern Mississippi, Hattiesburg, MS 39406 and (2) Natural Products Utilization Research Unit, USDA-ARS, University, MS 38677

The sensitivity of natural-based (sampangine, 4-bromosampangine, 4-methoxysampangine, benzo[4,5]sampangine, liriodenine Mel AMC-XIII-103, onychine, cryptolepine, and liriodenine CDH-II-37) and commercial fungicides (captan, kresoxim-methyl, fenhexamid, iprodione, benomyl, fenbuconazole, and cyprodinil) against economically important plant pathogenic fungi (Botrytis cinerea, Colletrotrichum acutatum, C. fragariae, C. gloeosporioides, Phomopsis obscurans, and P. viticola) was determined by in vitro microtiter assays. The effects of these fungicides on the morphology of spore germination, germ tube elongation, and mycelial growth of all the fungal isolates challenged was analyzed by microscopic germination and morphology observations. Data obtained from the microtiter assays was supported by the results from the germination and morphology observations. Sampangine was the most effective compound of all the experimental fungicides tested. It inhibited fungal germination and further growth of B. cinerea, C. acutatum, C. fragariae, C. gloeosporioides, and F. oxysporum. Colletotrichum acutatum was the most resistant species and C. gloeosporioides was the most sensitive species to all the sampangine analogs tested. Botrytis cinerea was the most sensitive species to all the commercial fungicides tested. Sampangine efficacy is comparable to that of commercial fungicides and it also shows low phytotoxicity in strawberry plants. Potential benefits and broad spectrum antifungal activity exhibited by the natural-based fungicide, sampangine, makes it a promising candidate for further greenhouse testing and field studies.

9:45 FACTORS INFLUENCING RUNOFF OF PESTICIDES FROM WARM SEASON TURFGRASSES

Peter Ampim (1*), Joseph H. Massey (1), Barry Stewart (1), M. Cade Smith (1), Ashley Andrews (1), Alton Johnson (2), and Kelvin Armbrust (3), (1) Mississippi State University, Mississippi State, MS 39762; (2) Alcorn State University, Alcorn State, MS 39096; and (3) Mississippi State Chemical Laboratory, Mississippi State, MS 39759

There is growing concern over the environmental fate of pesticides applied to turfgrasses. Of key interest is that pesticides used to maintain golf courses, home lawns etc., will pollute drinking water sources and impact human health. In addition, there is the possibility that elevated amounts of pesticides in water systems could impact the ecology of surface waters and health of wildlife. Understanding the fate of turf applied pesticides and predicting possible environmental concentrations requires knowledge of the factors affecting their movement or transport. This study was conducted using 2,4-D (2, 4-dichlorophenoxy acetic acid), flutolanil (trifluoro-3'-isopropoxy-o-toluanilide) and chlorpyrifos (O, O-diethyl hexahydro-4,7-methanoindene) applied at maximum label rates to two turfgrasses maintained as golf course and residential lawn on Brookville silty clay (fine montmorillonitic, thermic Aquic Chromudert). The turf species used were Tifway 419 bermuda grass (Cynodon dactylon [L] Pers. X Cynodon transvalensis Burtt-Davy) and Meyer zoysia grass (Zoysia japonica). The plots were 3.65 m X 9.14 m in size and sloped at 3%. The plot arrangement is a split design. Simulated rainfall was applied to the plots to generate runoff within 24 hours of pesticide application. Runoff from the plots was collected at 5 minutes intervals for each simulation event. The average rates of rainfall applied in the two events under consideration were 4 and 1.87 ml [h.sup.-1] respectively. Water solubility of pesticide, sorption and runoff have been identified as factors influencing pesticide runoff from preliminary data obtained. It is expected other factors will be identified in future simulations.

10:00 DETECTION AND PREVENTION OF RASPBERRY CROWN BORER IN BLACKBERRIES

Edward Heard*, Frank Matta, and Blair Sampson, Mississippi State University, Mississippi State, MS 39762

The purpose of this research is to provide blackberry growers with effective methods of early detection and control of raspberry crown borer (RCB). Objectives are to trap male RCB adults using phermone bait, monitoring populations of RCB living in soil outside infested crowns, and prevent spread of RCB from infested to nearby non-infested blackberries using applications of insecticide and entomopathogenic nematodes. Detailed procedures in conducting the experiment are outlined and initial test results are presented.

10:15 BREEDING VALUE AND ADOPTION OF DOMESTICATED TRAITS IN CULTIVATED CAPSICUM SPP

Ravi R. Chinthakuntla (1*), Frank Matta (1), Daniel Peterson (1), O.U. Reddy (2), and M.S. Rao (3), (1) Mississippi State University, Mississippi State, MS 39762; (2) West Virginia State University, Institute, WV 25112; and (3) Alabama A & M University, Normal, AL 35762

The objectives of this research are to identify superior pepper types with respect to horticultural characteristics, such as insect and disease resistance, yield and fruit characteristics, and to evaluate breeding germplasm by genotyping using microsatellites for estimation of diversity index. Preliminary results show that crossing success was higher within species compared to crossing between species. Capsicum annuum and C. chinense produced greater fruit yield. Most F1 progeny were more vigorous and produced greater yield than either parent. Southern blight was negligible on most F1 progeny, parent lines, and accessions. Microsatellite genotyping to estimate genetic diversity and validation of markers that are linked to various traits is in progress.

10:30 Break

10:45 DISTRIBUTION OF PHYTOPARASITIC NEMATODES OF COTTON IN THE YAZOO MISSISSIPPI DELTA

Julie A. Blessitt* and Gabe L. Sciumbato, Mississippi State University DREC, Stoneville, MS 38776

The three main parasitic nematodes of cotton in the Mississippi Delta are root-knot (Meloidogyne incognita), reniform (Rotylenchulus reniformis), and lance (Hoplolaimus). The root-knot nematode has traditionally been the most important. However, the reniform has increased in importance. Leflore, Sharkey, Coahoma, Tunica, Bolivar, Tallahatchie, Desoto, Marshall, Quitman, Sunflower, Washington, Humphreys, Holmes, Panola, and Yalobusha counties cotton acreage was randomly surveyed (approximately 10%) for nematodes. Soil samples were collected and their location referenced by GPS for future location. Nematodes were extracted using an elutriator with sugar flotation. Nematodes were identified and counted. Percent infestations of root-knot nematode ranged from 2% in Sharkey county to a high of 26% in Desoto county. Percent infestations of reniform nematode ranged from 3% in Desoto county to a high of 87% in Sharkey county. The lance nematode was found in a few locations. The acreage infested with the reniform nematode continues to increase from previous surveys. There are no commercial cotton varieties which are resistant to this nematode. Increased reniform infestation levels may in part explain "yield stagnation" recently observed in cotton production.

11:00 DEVELOPMENT OF MICROSATELLITE MARKERS FOR ABIES FRASERI FIR, THE COMMERCIAL CHRISTMAS TREE

Joseph A. Bowen (1*), C. Dana Nelson (2), Judith Williams (1), and Glen Johnson (2), (1) University of Southern Mississippi, Gulf Coast Research Laboratory, Ocean Springs, MS 39564 and (2) Southern Institute of Forest Genetics, Harrison Experimental Forest, Saucier, MS 39574

The Abies fraseri fir and A. balsamea are two of the most important commercial fir trees (Christmas trees). In recent years they have come under extreme ecological and environmental pressure and as a result their populations are in decline. The objective of this study was to examine the potential benefits that DNA markers offer in the development of resistant fir species. These markers originated from cloned intershort sequence repeat polymerase chain reactions (PCR), which enrich medium to highly repetitive DNA sequences. In total, 20 markers were isolated, eighteen of which were polymorphorphic or monomorphic. These markers can subsequently be applied to study populations of Abies fraseri fir The aim of this project was therefore to develop co-dominant DNA markers that would make it possible to analyze populations of the fir at considerably higher levels of resolution than was previously possible. This technique makes possible screening for cloned intershort sequence repeat polymerase chain reactions (PCR) an unknown number of loci. Genomic DNA was extracted from sixteen A. fraseri fir needle samples, and an intershort sequence repeat (ISSR) polymerase chain reaction was performed on extracted DNA using twenty different ISSR primers. Amplification products were used to isolate specific microsatellite DNA. Specific primers were designed to flank medium repetitive sequences present in several inserts, and were used to amplify the loci from genomic DNA of the original Abies fraseri fir. In this study, we have succeeded in developing eighteen primer sets that amplify loci from A. fraseri fir and A. balsamea. All eighteen of these primer sets have been used to amplify polymorphic and monomorphic loci from genomic DNA of A. fraseri fir and A. balsamea.

11:15 RESISTANCE OF ENTRIES IN THE MISSISSIPPI SOYBEAN VARIETY TRIALS TO PURPLE POD ROT CAUSED BY CERCOSPORA KIKUCHII

Bonnie B. Cook* and Gabe L. Sciumbato, Mississippi State University, DREC, Stoneville, MS 38776

Cercospora kikuchii attacks the seed, leaves, and pods of soybean plants leading to decreased seed quality and potential yield losses. A variety may be resistant to leaf attack but susceptible to pod or seed disease. Pod disease can completely rot pods under warm, humid environmental conditions. Extended rainfall in 2002 during pod fill for Maturity Group IV soybeans proved very favorable to the development of pod disease. Entire fields of disease susceptible varieties were destroyed. A method was developed to determine the resistance of soybean varieties to purple pod rot caused by Cercospora kikuchii. Entries in the Mississippi Soybean Varietal Trials were evaluated for resistance to purple pod rot. Disease free pods in the R6 growth stage were detached, surface disinfected with sodium hypochloride, washed with sterile water, and placed in moist chambers. Ten pods were sprayed with sterile water as a check, and ten were sprayed with a suspension of Cercospora kikuchii for each variety. Pods were incubated at 30[degrees]C for seven days and evaluated for pod disease. Two hundred seventy-seven varieties were evaluated. Thirty-one varieties were susceptible to purple pod rot, while 185 varieties were resistant. Sixty-one varieties were moderately resistant to moderately susceptible to pod disease. Varieties having moderately resistant to susceptible ratings could have significant yield losses due to disease under the right environmental conditions.

11:30 Divisional Poster Session

DUPLICITY OF PLANTS IN NUTRIENT UPTAKE WITHIN AGRICULTURAL DRAINAGE DITCHES

Robert Kroger (1*), Marjorie M. Holland (1), Matt T. Moore (2), and Charlie M. Cooper (2), (1) University of Mississippi, University, MS 38677 and (2) USDA-ARS, National Sedimentation Laboratory, Oxford, MS 38655

Agriculture drainage ditches are primary intercept wetlands in the amelioration of nutrient pollution from agricultural fields. Amelioration of nutrient pollution has wide reaching consequences on receiving water pollution and possibly implications for aquatic community structure and Gulf of Mexico hypoxia. Drainage ditches, as integral components of the agricultural landscape, remove surface run-off and act as major conduits of nutrients from agricultural lands to receiving waters. These ditches are prolifically abundant in wetland plants, providing additional surface area for microbial interactions as well as acting in a small, yet important assimilatory capacity. However, their assimilatory function is negated in winter with seasonal die-back and the release of assimilated nutrients into the system. The additional lack of cover, in a winter rainfall area allows faster water movement in the ditch. We tested the hypotheses of whether plants given the opportunity will firstly assimilate higher concentrations of nutrients, such as nitrogen and phosphorus, and whether with subsequent decomposition these concentrations are released back into the water column. Given the opportunity Leersia oryzoides, a dominant wetland ditch plant species, will assimilate significantly higher concentrations of nitrogen (p > 0.05) and phosphorus (p > 0.001) in above and belowground biomass. Subsequently, the senescence of aboveground biomass yields significantly higher levels of phosphorus and for longer periods of time. However, there were no significant differences in nitrate and nitrite levels which suggests that denitrification and microbial processes were removing these products from the system.

IMPROVING WATER USE EFFICIENCY IN RICE PRODUCTION USING MULTIPLE-INLET PLUS INTERMITTENT IRRIGATION HAS ENVIRONMENTAL BENEFITS

Ashley Andrews (1*), Joseph H. Massey (1), M. Cade Smith (1), Alton Johnson (2), Jim Thomas (1), and Peter Ampim (1), (1) Mississippi State University, Mississippi State, MS 39762 and (2) Alcorn State University, Alcorn State, MS 39096

The depth of the alluvial aquifer in the Mississippi Delta has been declining, on average, 27 cm [yr.sup.-1] (10.5 in [yr.sup.-1]) due primarily to the irrigation of row crops. Conventional rice irrigation involves flooding each rice paddy individually. As one paddy fills with water, the water overflows into the next lower paddy. This approach results in less rain holding capacity and the potential for water, as well as pesticides, to runoff the field. A new irrigation approach being investigated in this project involves multiple-inlet distribution of irrigation water coupled with intermittent irrigation techniques first investigated in Asia. Multiple-inlet irrigation allows each paddy to be filled at the same time and the water levels to be more closely regulated. Unlike conventional rice irrigation techniques, intermittent irrigation actually allows water levels in the rice paddies to naturally decline until one-half of the soil surface is exposed in the upper portions of the paddies. Preliminary field studies show that multiple inlet plus intermittent irrigation reduces water use in rice by ca. 50% with little difference in yield. By increasing the rainfall holding capacities of rice paddies, non-point source pollution from rice fields should also be reduced. As rice irrigation practices are made more efficient through careful planning and management, a number of environmental benefits could also occur.

FEEDING FREQUENCY, MULTIPLE STOCKING DENSITIES, AND THE EFFECT ON CELL GROWTH RATE OF TAHITIAN ISOCHRYSIS SP.

Jill Zednick* and Jeffrey M. Lotz, University of Southern Mississippi, Hattiesburg, MS 39406

The primary objective in culturing algae for aquaculture is to obtain the highest density in the shortest period of time. Isochrysis sp. is a popular alga in aquaculture because of its nutritional qualities allowing many marine animals to be grown to high densities in mass culture. The growth of an algal culture is denoted as a 'growth cycle' and is usually described by a sigmoid curve. The University of Southern Mississippi Department of Coastal Sciences executes mass cultures of Tahitian Isochrysis sp. at their Cedar Point aquaculture facility as food for Acartia tonsa. A two part experiment was conducted over a 14 day period to determine if there was any effect of number of feedings per day on Tahitian Isochrysis sp. cell density and if various inoculation densities resulted in different cell mass over a seven day period. Algal culture vessels used in these experiments consisted of 20L food grade plastic bags. Culture vessels were exposed to continuous lighting consisting of fluorescent and metal halide. Aeration was also continuous with the addition of carbon dioxide at a rate of approximately 5-10 PSI every five minutes for a seven second duration. Temperature and salinity were maintained at 22 [+ or -] 2[degrees]C, and 25 [+ or -] 1 ppt respectively. The effect of number of feedings on cell density was determined as not significantly different from the control (ANOVA: ([F.sub.2,5] = 1.142, p = 0.390) and the observed division rates for each of the three inoculation densities generated similar trends in growth over the seven day study period.

EFFECT OF OZONE ON THE QUALITY OF MINCED CHUB MACKEREL

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

Chub Mackerel (Scomber japonicus) is an abundant and underutilized fish in North America. It may have potential for production of mince-based products or surimi. The primary objective of this study was to evaluate the effects of ozone treatments at varying time intervals. We compared the composition, color and microbial quality of fish mince treated with an ozonizer. Moisture content was higher (80%) in ozone washed mince than (77%) raw mince. The protein and fat contents were lower in ozone washed 60 minutes mince compared to raw mince (18% and 1.7% vs. 20% and 2.2%). The ash content was higher (2.3%) in raw mince than in ozone treated (.2%-.3%). The color of raw mince (Hunter color meter model CR10) L-value 30.1, a-value 3.4, and b-value of 6.1 vs L-value 48.8, a-value 1.1, and b-value of 11.8 for ozone washed mince of 40 minutes. Microbiological quality, growth of spoilage bacteria, was slightly reduced with ozone washed 40 minutes over the raw fish mince using aerobic plate counts (APC) and psychrotrophic plate counts (PPC). Studies will continue on the effect of pH and ozone on fish mince to lighten color to improve consumer acceptability.

ROLE OF RHIZOCTONIA SOLANI AND PYTHIUM SP. IN THE SEEDLING DISEASE COMPLEX OF COTTON AND EFFICACY OF DIFFERENT METHODS OF FUNGICIDE APPLICATION FOR THEIR CONTROL

Brewer Blessitt (1*), Gabe L. Sciumbato (1), and Allen Henn (2), (1) Mississippi State University, DREC, Stoneville, MS 38776 and (2) MCES, Starkville, MS 39769

Cottonseed, (variety DP45 1 BR) were inoculated at planting with Rhizoctonia solani, Pythium sp. and a combination of both fungi. Three different methods of fungicide application (seed treatment Baytan, Thiran, Lorsban 30FL, Apron-FL; hopper-box DeltaCoat 11.75 oz/cwt; and in-furrow Terraclor Super X 18.8 G, 7 lb/A) were evaluated for their efficacy in control of diseases. Experimental design was a randomized complete block with factorial arrangement of treatments. Treatments were replicated four times. Stand counts were made 4 weeks after planting and yield data were collected. Plots which were not inoculated had the highest average seedling stands (78.9% at 4 weeks) and seed cotton yields (3634 lb per acre) of the inoculation factor plots. In the 2 years, trial inoculation with Rhizoctonia reduced stands by an average of 65.2% and seed cotton yields by an average of 865 lb/A. Pythium reduced stands by an average of 29.8% and seed cotton yield by an average of 171 lb/A. Untreated seed had the lowest average stand counts at 40.3% at 4 weeks and the lowest seed cotton yields of 2844.2 lb/A. followed by the fungicide seed treatment only. The hopper-box had the next lowest stand count at 55.2% and a yield of 3636.9 lb seed cotton/A. The infurrow, of the fungicide factor plots, had the highest stand at 63.7% and a yield of 3634.8 lb seed cotton/A. This research has shown that inoculation with Rhizoctonia solani or a mixture of both fungi causes highest stand losses and in-furrow sprays are the most effective method of controlling the diseases.

ESTIMATION OF FLAVONOL AND FLAVONE CONTENT OF WATERLEAF, PURSLANE, BASIL, CARROT, AND CORN USING ALUMINUM CHLORIDE COLORIMETIRC METHOD AND HPLC

Sandra L. Barnes*, Sheila A. Sanders, Johnnie Gibbs, Peter B. Ojung, and Shashank Kulkarni, Alcorn State University, Alcorn State, MS 39096

The flavonoid content of many vegetable crops has not been reported. In this study, the aluminum chloride colorimetric method was used to determine the total flavonol and flavone content of six vegetable crops or herbs: waterleaf, purslane, basil, carrot, and corn. High performance liquid chromatography (HPLC) was used to determine the presence or absence of specific flavonols (quercetin and kaempferol) and flavones (apigenin and leuteolin). Results show that waterleaf contains a very large amount of total flavonols and flavones, 25-31% dry weight. Purslane, basil, carrot, and corn contained 6.5-6.9%, 5.6-6.9%, 3.4-4.1%, and 1.2-1.8%, respectively. High amounts of quercetin were found in waterleaf, purslane, and carrots by HPLC.

CHELATE-INDUCED PHYTOEXTRACTION OF LEAD-CONTAMINATED SOILS BY TALL FESCUE (FESTUCA ARUNDINACEA SCHREB.)

Gloria Miller*, Maria Begonia, Gregorio Begonia, and Darla C. Gilliard, Jackson State University, Jackson, MS 39217

Preliminary studies indicated that tall fescue (Festuca arundinacea cv. Spirit) can tolerate and accumulate significant amounts of lead (Pb) in its shoots when grown in Pb-amended sand. To further evaluate the suitability of this species for phytoextraction, a study was conducted to determine whether the addition of ethylene-diamine-tetra-acetic acid (EDTA) alone or in combination with acetic acid can further enhance the translocation of Pb to the shoot. Seeds were planted in plastic pots containing soil, peat, and sand spiked with various levels (0, 1000, 2000 mg Pb/kg dry soil) of lead. Six weeks after planting, aqueous solutions (0.5 mmol/kg dry soil) of EDTA and acetic acid were applied to the root zone, and all plants were harvested a week later. Results revealed that tall fescue was relatively tolerant to moderate levels of Pb as shown by nonsignificant differences in root and shoot biomass among treatments. However, there was a slight reduction in root and shoot biomass of plants exposed to the highest Pb level in combination with the two chelates. Root Pb concentrations increased with increasing levels of soil-applied Pb. Further increases in root Pb concentrations were attributed to chelate amendments. Translocation index was significantly enhanced with chelate addition especially when both EDTA and acetic acid were used. Chelate-induced increases in translocation indices led to higher shoot Pb concentrations.

EVALUATION OF DIFFERENT CULTIVARS OF EGGPLANT (SOLANUM MELONGENA) FOR PRODUCTION POTENTIAL

O.P. Vadhwa (1*), R. Reddy (1), Dovi Alipoe (1), James Spiers (2), and D.S. Marshall (2), (1) Alcorn State University, Alcorn State, MS 39096 and (2) USDA-ARS, Small Fruit Research Station, Poplarville, MS 394070

Six Different cultivars of eggplant (Solanum melongena) were evaluated for their production potential. Cultivars included were Nisha, Preeti, Kokila and Krishna from India. A Japanese cultivar, Ichiban, and American eggplant, Black Beauty, were also included in this study. Eggplant seeds were planted in the greenhouse and the seedlings produced were planted in the field on May 11, 2004. Seedlings were planted .60 meter apart in rows which were set .9 meter apart. Five plants per plot for each cultivar were used to collect yield data. Each treatment was replicated four times. Maximum yield was produced by cultivar Krishna, followed by Nisha, Black Beauty, and Kokila. Japanese cultivar, Ichiban, was least productive. First harvest of eggplants was July 6, 2004 (55 days after transplanting) and last harvest was Nov. 11, 2004.

RICE YIELD RESPONSES TO NITROGEN FERTILIZATION RATES APPLIED AT EARLY VEGETATIVE GROWTH STAGES

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

Rice response to nitrogen fertilization is affected by soil type and crop management. Furthermore, rice has been shown to respond to nitrogen applications at two important growth stages, namely early vegetative and reproductive. This study was conducted to determine the optimum rate of nitrogen that should be applied at the early vegetative stage. This corresponds to the period prior to the normal cultural practice of flooding the rice crop. Yield response curves were developed using four pre-flood nitrogen application rates on plots established on two different soil types in the Mississippi 'Delta.' Four rice varieties were evaluated. Treatment effects and the influence of soil and climatic factors on yield will be presented.

RELATIONSHIPS BETWEEN IRON CONTENT, SOIL MORPHOLOGY AND WATER TABLE DEPTH FOR AN ALFISOL IN THE MISSISSIPPI RIVER ALLUVIAL FLOODPLAIN

G.L. Jackson (1*), W.L. Kingery (1), M. Lilly (2), and C. Hatcher (2), (1) Mississippi State University, Mississippi State, MS 39762 and (2) USDA-NRCS, Jackson, MS 39269

Groundwater levels and water table fluctuations are routinely estimated by soil scientists from a soil's morphology, mainly the soil color. A significant portion of soil colors are related to the presence or absence of iron. Gray colors are associated with saturated and chemically reducing soil environments, while yellowish-brown colors are due to aerobic and chemically oxidizing conditions. Soils without excess water during the year usually are aerated and yellowish-brown-colored. Those with high water tables during some part of the season exhibit gray coloration at the depth of the high water mark and below. In order to evaluate the usefulness of soil classification for assessing the soil-water state, water table measurements were made in an alfisol in the Mississippi River alluvial floodplain. Soil profile descriptions, including redoximorphic features, were performed. Total, ammonium oxalate-extractable, and dithionite-citrate-extractable iron concentrations were measured on soil samples collected at 7.5-cm intervals from the surface to a depth of 2 meters. This paper describes the relationships between water table depths and duration, soil colors and the distribution of iron content. Environmental conditions affecting soil color formation and implications of soil morphological criteria in determining water table characteristics will be discussed.

A NOVEL APPROACH TO DETERMINE ATTACHMENT STRENGTH OF SELECTED FOODBORNE PATHOGENS

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

Most methods for quantifying viable cells in biofilms use swabbing, shaking or mild sonication. These result in large errors. The objective of this study was to measure the in vitro attachment of selected pathogenic microorganisms by a novel method. The Blot succession method used coverslips colonized with pathogens in tryptic soy broth that were blotted onto a tryptic soy agar plate for one minute. The process was repeated through a succession of agar plates. The mini-column method used colonized glass beads that were packed in a column. The packed column was attached to a fraction collector with 10 test tubes (10 fractions) and filled with PBS buffer (pH 7.0). In all instances, the number of recovered colonies per plate or fraction decreased exponentially with plate succession number. It is our proposition that the removal exponent from both methods could be used as a simple, inexpensive and effective measure of the strength of attachment grown under different environmental conditions. These methods will prove useful in the design of treatment regimes for surface hygiene and in the selection of suitable materials.

PATHOGENS AND SPOILAGE BACTERIA OF CATFISH FILLETS AS AFFECTED BY LOW-DOSE X-RAY IRRADIATION

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

A number of researchers have reported that low-dose irradiation could improve safety and shelf-life of various species of fish. X-rays are commonly used in hospitals, but this technology has recently been developed with enough intensity and penetration to process a variety of foods on a commercial scale. The effect of low-dose, x-ray irradiation (0, 2, and 3 kGy) on inoculated pathogens (Listeria monocytogenes, Lm and Salmonella Thyphimurium, ST) and natural spoilage bacteria (psychotropic bacteria: PPC, anaerobic bacteria: AA, and lactic acid bacteria: LAB) of catfish fillets was studied over the experimental period of 24 d. The irradiation doses of 2 and 3 kGy eliminated Lm and ST which were inoculated onto catfish fillets at levels of 4.8 and 4.7 log CFU/g, respectively. There was no recovery of either pathogen from fillets for the experimental period. Doses of 2 and 3 kGy reduced populations of psychrotrophs by 46%, aerobes by 62%, and lactic acid bacteria by 68%. Further post-irradiation reductions of spoilage bacteria were observed. This might be attributed to further death of injured cells. Spoilage bacteria, which were enumerated from catfish fillets treated with 2 kGy irradiation, regained their growth after 16 d of storage, but those obtained from catfish fillets exposed to 3 kGy could not restore their growth throughout the experimental period. Shelf-life of catfish fillets exposed to 2 or 3 kGy irradiation could be extended by more than 24 d at 2 [degrees]C, with the added safety of possibly eliminating pathogens.

HIGH TEMPERATURE STORAGE SHELF-LIFE OF FRESH CATFISH FILLETS

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

Temperature abuse is the main factor responsible for shelf-life and spoilage of catfish fillets. Including handling abuse due to temperature in shelf-life models is very important. The objective of this experiment was to study the shelf-life and spoilage pattern of fresh catfish fillets stored at 10 [degrees]C and 20 [degrees]C. Fresh catfish fillets were packed in polyethylene bags and stored at 10 [degrees]C and 20 [degrees]C. Each six to twelve hours, microbiological quality, sensory assessment and water holding capacity of stored fillets were examined. Aerobic (APC) and psychrotrophic (PPC) plate counts of fresh catfish fillets stored at 10 [degrees]C had a lag phase of 24 h. The APC and PPC of fillets stored at 20 [degrees]C had no lag phase and grew immediately. Sensory descriptions indicated that fresh catfish fillets stored at 20 [degrees]C lost acceptability in 18-24 h whereas those stored at 10 [degrees]C lost acceptability in 72 h. Spoilage of catfish fillets stored at both temperatures was reached when APC and PPC levels reached [10.sup.8] CFU/g. The percentage of shrinkage of fillets increased with storage time (lower water holding capacity), but the values varied greatly on individual fillets.

THURSDAY AFTERNOON

Classroom A

2:00 OFF-FLAVOR INTERVENTION FOR PROCESSED CATFISH FILLETS

Chonthida Kaewplang*, Juan L. Silva, and Taejo Kim, Mississippi State University, Mississippi State, MS 39762

2-methylisoborneol (MIB) (musty) and geosmin (earthy), which are fat-soluble off-flavor compounds found throughout catfish (Ictalurus punctatus) muscle, reduce consumer acceptability of catfish products. About 50% of the ponds could be off flavor during the warm months. The objective of this experiment was to decrease or eliminate off-flavor in catfish during processing. Diffusion studies, using 0.5% [H.sub.2][O.sub.2] as the oxidation substance (dipping, injecting and tumbling) showed that there were no differences (p > 0.05). Thus, dipping was selected as the simplest method to carry out the screening of off-flavor reducing substances. The effect of carbonated drinks (Sprite Seven-up and commercial carbonated water) on off-flavor of catfish fillets was investigated then. Sensory evaluation, based on intensity of off-flavor was performed utilizing a 5-point hedonic scale. For smell of fresh fillets, control and commercial carbonated water were not significantly different, while Sprite and Seven-up lowered of flavor (p > 0.05). Similar results were observed on cooked fillets. Seven-up provided the best (p < 0.05) result compared to control, commercial carbonated water, and Sprite The high intensity citrus aroma (lemon, lime), was noted in Seven-up followed by Sprite and helps mask the off flavor while adding a pleasant flavor. Therefore, Seven-up (or a formulation derived from it) can be used to decrease the off-flavor of catfish fillets.

2:15 USING RESPONSE SURFACE METHODOLOGY TO OPTIMIZE A CATFISH PRODUCT

John McGillivray*, Juan L. Silva, Taejo Kim, Mark W. Scilling, Youkai Lu, Chonthida Kaewplang, Somsamorn Gawborisut, Jelena Stojanovic, Wei-chun Chen, and Sovann Kin, Mississippi State, University, Mississippi State, MS 39762

Utilizing catfish (Ictalurus punctatus) nuggets and catfish mince, less popular parts of the catfish to make a reformed product will enhance the value of catfish. The objective of this research was to use response surface methodology to formulate a fish patty with optimum quality that consists of minced catfish and catfish nuggets. Frozen catfish nuggets were finely chopped for less than 10 sec. Both the mince and the nuggets were thawed and then mixed at ratios of 0, 50, and 100% (mince to nugget). These raw materials were then combined with 0%, 0.5%, 1% whey protein isolate (WPI), and mixed for 2, 4, 6 min in a food mixer along with 1% salt (NaCl) and 0.3% sodium tripolyphoshate (STPP). The patties were hand made with a patty maker mold so that each patty weighed approximately 70 g. Color, texture (shear and compression), water holding capacity, cook yield, and sensory ratings were collected based on a central composite design. The color of the patties tended to be lighter with higher WPC, and patties mixed for six minutes tended to have higher shear and compression forces. Long mixing times increase extraction of salt-soluble proteins which in turn give strength to reformed muscle meat products.

2:30 SSR AMPLIFICATIONS FOR PEPPER GENOME CHARACTERIZATION

Preeti Kumar*, Umesh Reddy, and Padmavathi Nimmakayala, University of Mississippi, University, MS 38677 and West Virginia State University, Institute, WV 25112

Abundance of polymorphism in repeat motifs of genome is well documented in several plant and animal species. Such motifs, known as SSRs (Simple Sequence Repeats) or microsatellites, can be easily exploited as potential markers using modern PCR technologies. Saturation of Capsicum genetic maps with the SSRs will speed up mapping and further isolation of genes that are governing important traits. To date, microsatellites have not been used extensively in pepper, in part because of the complex and labor-intensive methods identifying microsatellites from large genomes. The genus Capsicum comprises > 30 species, among which, five major cultivated species (C. annuum, C. chinense, C. frutescens, C. baccatum and C. pubescens) are well known. In the present study we used 20 SSRs to detect polymorphisms between these types. The objective of the study is to understand the extent of gene flow with in the domesticated forms. Our study identified distinct diagnostic SSR alleles to identify various cultivated and wild taxa. The average number of alleles per microsatellite being 2 (range 2-4 alleles per locus), this class of markers appears to be highly polymorphic. Allelic diversity and polymorphism among various pepper types will be discussed.

3:00 Divisional Business Meeting and Awards
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Publication:Journal of the Mississippi Academy of Sciences
Geographic Code:1USA
Date:Jan 1, 2005
Words:6458
Previous Article:The convergence of science and technology in Mississippi: I. advancing the frontiers of biomedicine (1).
Next Article:Cellular, Molecular and Developmental Biology.


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