bluuebunny/crossref_metadata_2025 huggingface dataset:
FIELD ESTIMATION OF NITRATE LOAD FROM VEGETABLE FIELDS IN THE CARIBBEAN BASIN
Authors: Simonne Eric , Studstill D. , Dukes M. , Hochmuth G. , Hochmuth R. , Roka F. , O'Hallorans J. , Gazula A.
Published: February 2019

The development of best management practices (BMP) and the alloca-tion of pollution among land users in a watershed (TMDL) requires an understanding of the effect of cultural practices on both yields and nutrient leaching below the root zone. `Florida 47' tomato and `La Estrella' tropical pumpkin were grown on plasticulture using combinations of UF–IFAS recommended N and irrigation rates in a 1-ha field in 2004. Average N and irrigation rates over the whole field were 100% and 80%, respectively. Nitrate movement was assessed with twenty-four 1-m-long drainage lysimeters in each plot and ten 7-m-deep wells in and around the field Lysimeters and wells were sampled every 2 and 3 weeks throughout the year, respectively. Leachate volume and concentration in the drainage lysimeters were highly variable. Except shortly after the 25-cm rain due to hurricane Jeanne, most leachate volumes were <1 L·m–1. Annual NO3-N mean treatment load ranged between 7 and 15 kg·ha–1, but these differences were not significant due to high variability (CV = 175%). Single-lysimeter annual highest load was 39 kg·ha–1 of NO3-N (17.5% of N applied). In 2004, NO3-N concentration in well water was <1, ranged between 15 and 35, ranged between 0 and 10 mg·L–1 NO3-N in the up-stream control, inside, and perimeter wells, respectively. These concentrations are in the same ranges as those observed in this field in previous years (1997–2003) and often exceeded the 10 mg/L drinking water standard. Because NO3-N discharge into the environment may occur after the growing season, BMPs should be implemented on a year round basis. The methodology used in load measurement should be improved to better account for spatial variability.
PLASTIC MULCHED BED WIDTH EFFECTS ON PEPPER AND CANTALOUPE YEILD
Authors: Kelley William Terry , Langston David B.
Published: February 2019

The phase out of methyl bromide has precipitated a need to reduce usage of the all purpose fumigant. Reduction in methyl bromide use can extend the life of existing stocks and make it more likely to continue critical use exemption for future production. Traditional widths for plastic mulch covered beds in Georgia ranges from 32 to 36 inches. By reducing bed top widths, it could be possible to reduce the amount of methyl bromide applied by as much as 60%. The objectives of this work were to evaluate the effects of narrower bed tops and lower rates of methyl bromide on pepper and cantaloupe growth and yield. Bed top widths of 36, 30, and 24 inches were each tested with broadcast rates of 400 and 300 lb/acre of both 67:33 and 50:50 methyl bromide-chloropicrin at Tifton, GA in the fall of 2005. Bed widths were the main plot and methyl bromide rates the sub plot. Plots were 20 feet long with two rows of pepper planted per bed with 12 inches between plants and one row of cantaloupe planted per bed with two feet between plants. All beds were on 6-ft centers and fertilizer rates were constant across plots within a crop. There were four replications. Otherwise normal cultural practices were employed. Crops were harvested at maturity and data collected on yield and plant growth. Pepper yields were depressed by early cold weather. The 24-inch bed tops produced significantly lower yields of extra large, large and total fruit, but had greater top dry weight and root fresh weight than the 36-inch beds. There were no differences found among methyl bromide rates for cantaloupe or for pepper except extra large fruit were greater at the highest rate compared to the lowest. There were no differences among bed top widths for cantaloupe yield or plant growth.
TOMATO IN ROW SPACING RESPONSES AND IMPLICATIONS
Authors: Downes John D.
Published: February 2019

Celebrity Hybrid tomatoes were grown in six ft rows at spacings of 16, 19.2, and 24 inches, equivalent to 4506, 3755, and 3004 plants/acre (in 6008.3-ft planted row/acre) using BPE mulch, seep hose irrigation and Florida weave trellising. Thirty-eight-day marketable yields were 2192, 2273, and 2049 lb boxes (25 lb)/acre respectively, and 88-day marketable yields were 2533, 2917, and 2665 boxes/acre. Estimated spacings maximizing 38- and 88-day marketable yield (Ymax) were 18.37 inches (3925 ppa, Ymax 2274 box/acre) and 19.61 inches (3677 ppa, Ymax 2919 boxes/acre), respectively. Using a combined plant and staking cost of $1.00/plant and marketable tomato price of $2.50/box, the optimal spacings were estimated at 21.71 inches for 88 days (3321 ppa, 2848 boxes/acre), and 22.64 inches for 38 days (3185 ppa, 2126 boxes/acre). Yields increased almost linearly thru the first 38 days of harvest, slowed due to low fruit set (high temperatures), then resumed augmentation to day 88. Fruit size declined about 20% from early to late season. Ymkt as percent of total was highest at widest spacing (78.0% vs. 74.3% and 74.6% for other two). Higher yields/a were obtained only in first 10 days from the closest spacing. Thereafter wider spacings generally gave higher yields/acre. Yields per plant increased with spacing. Yield fluctuations over the season have implications for labor management. Plants per acre and closely associated costs (setting, trellising) impacted estimated optimal populations and thus spacings.
OPTIMIZATION OF DRAINAGE LYSIMETER DESIGN FOR FIELD DETERMINATION OF NUTRIENT LOADS
Authors: Gazula Aparna , Simonne Eric , Dukes Michael , Hochmuth George , Hochmuth Bob , Studstill David
Published: February 2019

Collecting leachate from lysimeters installed in the field below vegetable fields may be used to quantify the amount of nitrogen released into the environment. Because limited information exists on the optimal design type and on the effect of design components on lysimeter performance, the objective of this study were to identify existing designs and their limits, assess cost of design, and test selected designs. Ideally, lysimeters should be wide enough to collect all the water draining, long enough to reflect the plant-to-plant variability, durable enough to resist degradation, deep enough to allow for cultural practices and prevent root intrusion, have a simple design, be made of widely available materials, and be cost-effective. Also, lysimeters should not restrict gravity flow thereby resulting in a perched water table. Previous study done with a group of free-drainage lysimeters (1-m-long, 45-cm-wide, installed 45-cm-deep) under a tomato-pumpkin-rye cropping sequence resulted in variable frequency of collection and volume of leachate collected (CV of load = 170%). Improving existing design may be done by increasing the length of collection, lining the lysimeter with gravel, limiting the depth of installation, and/or breaking water tension with a fiberglass wick. Individual lysimeter cost was estimated between $56 to $84 and required 9 to 14 manhours. for construction and installation. Costs on labor may be reduced when large numbers of lysimeters are built. Labor needed for sampling 24 lysimeters was 8 man-hr/sampling date. Because load may occur after a crop, lysimeter monitoring and sampling should be done year round.
RECENT USDA–ARS BLUEBERRY CULTIVAR RELEASES
Authors: Stringer S.J. , Spiers J.M. , Draper A.D.
Published: February 2019

Two new southern highbush blueberry cultivars, `Dixieblue' and `Gupton', will provide growers with new blueberry cultivars having excellent fruit quality that ripen relatively early in the season, during the profitable early fresh-market window. Berries of `Dixieblue' are light blue, medium in size, and their flat shape makes them most attractive. `Gupton' is very productive and berry quality is also excellent. The performance of these cultivars represent an improvement over most currently available southern highbush blueberry cultivars due to 1) their durability and performance on both upland and sandy soils endemic to the Gulf Coast and 2) consistent production of high quality fruit that will meet the demand for early ripening fresh-market blueberries. The new rabbiteye blueberry cultivar, `DeSoto', represents an improvement over currently available rabbiteye blueberry cultivars for late-season production. `DeSoto' produces medium-to-large fruit having excellent color, flavor, and firmness Plants of `DeSoto' are productive, vigorous but semi-dwarf, upright and spreading. It's semi-dwarf growth habit, which is unique among currently grown rabbiteye blueberries, results in bushes that attain a maximum height of about 2 meters upon maturity, reducing the necessity of top-pruning that is required for all other cultivars. `DeSoto' blooms two to three weeks later than early-to-mid season cultivars such as `Climax' and `Tifblue', providing insurance against late-spring freezes. Similarly, its fruit mature 21 to 14 days or more, respectively after these same cultivars. `DeSoto' will provide niche market blueberry growers with a new cultivar having productivity, plant vigor, fruit quality, and very late ripening period that will extend their marketing season. The new evergreen ornamental blueberry, `Native Blue', is low growing, compact and finely branched with small glaucous leaves, traits that are quite typical of V. darowii. `Native Blue' has beautiful foliage that changes color in different seasons. Mature leaves are darker green while newer growth exhibits a light pinkish hue that changes to a bluish green. Other desirable characteristics of `Native Blue' are its dwarf growth habit, hardy and vigorous growth, and its capacity for a high level of fruit production that serves as an attractant to birds and other wildlife. `Native Blue' will provide southeastern U.S. nurserymen, landscapers, and homeowners with a novel and beautiful new ornamental shrub that will complement plantings of azaleas, camellias, crepe myrtles, etc.
EFFECT OF ROOTSTOCK ON YIELD AND QUALITY OF `CABERNET FRANC' (VITIS VINIFERA) IN OKLAHOMA
Authors: Stafne Eric T. , McCraw B. Dean , McGlynn William G. , Striegler R. Keith
Published: February 2019

Rootstocks can offer benefits such as pest resistance, tolerance of certain soil characteristics and tolerance of salts and salinity. The objective of this study was to determine if `Cabernet Franc' grafted onto various rootstocks differed in a number of measured yield and quality variables. The plots consisted of Clone 1 `Cabernet Franc' with four different rootstocks: 1103 Paulsen, 140 Ruggeri, 3309 Couderc, and St. George. Rootstock did not have much effect on the yield or quality of fruit produced by `Cabernet Franc'. Although not significantly different, the overall yield of 3309C appears to be lower than the other rootstocks. With further data, it might be possible to identify annual climate patterns that favor one rootstock over another with respect to certain quality attributes. One particular problem with `Cabernet Franc' in Oklahoma is its tendency to overbear, thus resulting in uneven ripening.
`REBEL': A NEW EARLY RIPENING SOUTHERN HIGHBUSH BLUEBERRY CULTIVAR
Authors: NeSmith D. Scott
Published: February 2019

A new southern highbush blueberry cultivar named `Rebel' was released in 2005 by The University of Georgia. It is a very early season cultivar with large fruit having a medium to light blue color, and a small, dry picking scar. `Rebel' berry firmness is good, while flavor is only average. The new cultivar flowers 3 to 4 days before `Star' and ripens 6 to 9 days before `Star' in south and middle Georgia. `Rebel' plants are highly vigorous, very precocious and have a spreading bush habit with a medium crown. Yield has been similar to or greater than `Star' in south Georgia. Leafing has been excellent, even following mild winters. Rebel has an estimated chill requirement of 400 to 450 hours (<7 °C). Propagation is very easily accomplished using softwood cuttings. Plants of `Rebel' are self-fertile to a degree, but should be planted with other southern highbush blueberry cultivars with a similar time of bloom for cross-pollination (`Emerald' and `Star' suggested). `Rebel' is new, so planting on a trial basis is recommended. `Rebel' requires a license to propagate. For licensing information and/or a list of licensed propagators, contact the Georgia Seed Development Commission, 2420 S. Milledge Avenue, Athens, GA 30606; or visit their web-site at www.gsdc.com.
`CAMELLIA': A NEW MIDSEASON SOUTHERN HIGHBUSH BLUEBERRY CULTIVAR
Authors: NeSmith D. Scott , Draper Arlen D.
Published: February 2019

A new southern highbush blueberry cultivar named `Camellia' was released in 2005 by The University of Georgia and the USDA–ARS. `Camellia' is a hybrid containing mostly Vaccinium corymbosum and a small amount of V. darrowi. The new cultivar was selected in 1996 at the Coastal Plain Experiment Station in Tifton, Ga. from a cross of MS-122 × MS-6, and was tested as TH-621 in plantings at Alapaha, Ga. beginning in 1998. `Camellia' has an estimated chill requirement of 450 to 500 hours (<7 °C). It is an early- to mid-season cultivar, having berries that are large, with a very light blue color, and a small, dry picking scar. Berry firmness is good and flavor is very good. `Camellia' flowers 5 to 8 days after `Star' and `O'Neal' in south Georgia, and ripens 4 to 9 days after `Star', and with `O'Neal'. Plants are highly vigorous, with strong cane growth and an open, upright bush habit and a narrow crown. Yields have been similar to `Star' and greater than `O'Neal'. `Camellia' should be planted with other southern highbush blueberry cultivars with a similar time of bloom for cross-pollination (`Star' and `O'Neal' suggested). It is recommended on a trial basis at this time. `Camellia' requires a license to propagate. For licensing information and/or a list of licensed propagators, contact the Georgia Seed Development Commission, 2420 S. Milledge Avenue, Athens, GA 30606; or visit their website at www.gsdc.com.
PERFORMANCE OF 18 JALAPENO VARIETIES IN WHOLE PACK AND SAUCE
Authors: Wilson Paul
Published: February 2019

Jalapeños are versatile peppers with both green and mature-red peppers used fresh and in processed products. Peppers can be dried, pickled whole in brine or as salted mash for sauces. Mature fruit can also be smoked and dried to produce chipotle which can be used in several ways including preparation of sauces. Although there are many individual cultivars of jalapeño peppers available, little is known of their processing characteristics. Most food processors still rely on fresh-market supplies rather than contracting specific cultivars which might provide better processing characteristics. A study was begun in Summer 2005 at LSU to provide information concerning the processing characteristics of commonly available jalapeño cultivars. Over a 3-year period, each cultivar will be evaluated in fresh form, as pickled whole fruit, as salted mash and as smoked chipotle. Besides good cultural production qualities, pepper cultivars that will be manufactured into processed products should have 1) acceptable and consistent heat content, 2) good stable color and, 3) consistent/suitable size (for whole pack). Seventeen jalapeño cultivars were evaluated in fresh green, brine-cured green and mature-red state for fruit surface color, average fruit weight, dry weight, and percent seed.
TRANSPLANT AND STAND SURVIVABILITY STUDIES IN SWEETPOTATOES
Authors: Villordon A.Q. , Franklin J.W. , Talbot T.P. , Cannon J.M. , McLemore W.
Published: February 2019

Transplant survivability is important in achieving consistent economic yields in sweetpotatoes. We are conducting a series of studies that investigate the role of transplant quality in sweetpotato yield. In 2004, in addition to investigating the role of transplant diameter, we also investigated the influence of transplant water (about 6 oz per hill) on stand and yield. Even though rainfall events were regular and mean rainfall during the growing season was above average for the year, there was a significant increase in US#1 yield (23.57%) among plots derived from thick transplants (≥0.25 inches, no transplant water) versus thin transplants (no transplant water). There was a 44.16% increase in US #1 yield among plots planted with thick transplants vs. plots with thin transplants (with transplant water). In 2005, there was also a significant difference (14%) in US #1 yield between plots planted to thick and thin transplants, respectively. This indicates the possible role of transplant thickness on stand and yield. We also investigated the relationship between root spacing during bedding on cutting diameter as well as a farmer's practice of planting two transplants per hill. In both preliminary tests, no differences among the treatments were observed. Additional studies are planned to investigate the possible use of chemical-based treatments to enhance transplant thickness and survivability.
YEAR TWO: EFFECTS OF GRAFTING ON WATERMELON YIELD AND QUALITY
Authors: Roberts Warren , Bruton Benny , Fish Wayne , Taylor Merritt
Published: February 2019

This is the second year of research on the effects of grafting watermelon (Citrullus lanatus) onto rootstocks of squash and gourd. The study was conducted at Lane, Okla., in both 2004 and 2005. This report deals with the results from 2005. Treatments consisted of watermelon cultivars SF 800, SS 5244, SS 7167, SS 7177, and SS 7187 from Abbot & Cobb Seed Co., grown on their own roots, or grafted onto rootstocks of RS1330, RS1332, RS1420, or RS 1422. Additional controls consisted of nongrafted cultivars Sangria, Royal Sweet, Jubilee, and Jamboree. Two fields were planted, with three replications per field. Plants were grown on 1-m centers, with rows 3 m apart. Yields from grafted plants were higher than average farm yields in Oklahoma, but were lower than yields from the nongrafted plants in this experiment. Sugar content, measured as soluble solids, was in some cases lower with the grafted plants than with the nongrafted plants. Lycopene content of fruit from grafted plants was similar to that of fruit from nongrafted plants. Fruit firmness, as measured by a penetrometer, was significantly greater in the grafted fruit than in the nongrafted fruit. This increase in fruit firmness should be of significance to the fresh-cut fruit industry. Matching of scions with appropriate rootstocks was important, as interactions did occur. Rootstock 1332 generally had lower sugar content and yield than did the other rootstocks, but not with all scions. Certain combinations of rootstock and scion were significantly superior to other combinations.
Controlled Environments for Production of Value-added Food Crops with High Phytochemical Concentrations: Lycopene in Tomato as an Example
Authors: Kubota Chieri , Thomson Cynthia A. , Wu Min , Javanmardi Jamal
Published: February 2019

Plants produce various phytochemicals that are of nutritional and medicinal value to humans. Phytochemicals having antioxidant capacity are drawing increased interest from consumers. Population studies among Americans have consistently demonstrated inadequate consumption of fruit and vegetables. Improving intake of fruit and vegetables has been a major public health effort for many years with minimal success. Given this, it seems opportunistic to consider other approaches to enhance the nutritional quality of the American diet. One plausible approach is the development of fresh produce containing a greater concentration of phytochemicals known to improve health, thus while consuming fewer servings of produce, Americans would still have significant exposure to health-promoting food constituents. Controlled environments provide a unique opportunity to modify the concentrations of selected phytochemicals in fruit and vegetables, yet practical information is limited regarding methods effective in optimizing antioxidant capacity. Our research at the University of Arizona Controlled Environment Agriculture Program has shown that application of moderate salt stress to tomato plants can enhance lycopene and potentially other antioxidant concentrations in fruit. The increase in lycopene in response to salt stress in the tomato fruit was shown to be cultivar specific, varying from 34% to 85%. Although the specific biological mechanisms involved in increasing fruit lycopene deposition has not been clearly elucidated, evidence suggests that increasing antioxidant concentrations is a primary physiological response of the plant to the salt stress. Another experiment showed that low temperature during postharvest increased antioxidant capacity of tomato fruit while it maintained the lycopene concentration. More detailed study in this area is needed including accumulation of antioxidant phytochemicals as affected by environmental conditions during the cultivation and the postharvest.
Comparison of Self- and Cross-pollination on Pollen Tube Growth, Seed Development, and Germination in Crapemyrtle
Authors: Pounders Cecil , Reed Sandra , Pooler Margaret
Published: February 2019

Crapemyrtle (L. indica and L. indica × L. fauriei hybrids) is one of the most popular flowering landscape plants in the U.S. Although many cultivars have been developed through breeding efforts, little has been published on the reproductive biology of the genus. The objective of this study was to evaluate barriers to successful self-seed production in crapemyrtle. Self-compatibility was assessed by comparing pollen tube growth, fruit and seed production, and seed germination following controlled self- and cross-pollinations. Observations of pollen tube growth at intervals up to 24 hours after self- and cross-pollination indicated no barriers to self-fertilization acting at the stigmatic or stylar level in L. indica, L. fauriei or cultivars derived from inter-specific hybrids of these two species. Self-pollinations of `Catawba', `Whit IV', `Tonto' and `Tuscarora' had lower percent seed pod set and seed germination than did cross-pollinations of these cultivars. The number of seeds per pod was lower when `Catawba', `Whit IV' and `Tuscarora' were self-rather than cross-pollinated, but no difference between `Tonto' self- and cross-pollinations was observed. When decreased pod set is combined with much lower seed germination for self-pollinations, selfing of crapemyrtle is extremely unproductive when compared to cross-pollination. A late-acting self-incompatibility system or inbreeding depression is indicated for L. indica and inter-specific crosses with L. fauriei.
Frequency and Timing of Leaf Removal Affect Growth and Podophyllotoxin Content of American Mayapple in Shade
Authors: Cushman Kent E. , Moraes Rita M. , Gerard Patrick D. , Bedir Ebru , Silva Bladimiro , Khan Ikhlas A.
Published: February 2019

Leaves of American mayapple (Podophyllum peltatum) are being investigated as an alternative and renewable source of podophyllotoxin, a pharmaceutical compound used in the manufacture of several drugs. This study examined long-term performance of mayapple populations subjected to different harvest strategies. A naturally occurring population in shade was subjected to leaf removal treatments of frequency (every year, every 2nd or 3rd year) or timing (early or late season). Plots were 1.0 m2, established during Spring 2001, and treatments were applied from 2001 to 2004. Control plots not previously harvested were also included each year. Plants did not tolerate the severest of leaf removal treatments: early harvest time in combination with annual harvest frequency. Early annual harvests reduced total leaf dry mass and total leaf area in a quadratic manner. Late harvest conducted annually, and early harvest conducted every other year, also reduced leaf dry mass and area but not as much as early annual harvest. Plants harvested every year, early, or early every year produced fewer sexual shoots than other treatment combinations. Contents of α-peltatin, β-peltatin, and total lignans were higher for leaves harvested early than those harvested late during each year of the study, demonstrating that lignan contents were affected by leaf age and not treatment. In conclusion, our results for plants grown in shade show that leaves can be removed late in the growing season every 2nd or 3rd year or early every 3rd year without reducing long-term performance of the population. This is more restrictive than that reported for populations in full sun where plants tolerated late harvests every year.
Temperature and Photoperiod Regulate Flowering of Potted Miltoniopsis Orchids
Authors: Lopez Roberto G. , Runkle Erik S.
Published: February 2019

Miltoniopsis orchids have appealing potted-plant characteristics, including large, fragrant, and showy pansylike flowers that range from white and yellow to shades of red and purple. Scheduling orchid hybrids to flower on specific dates requires knowledge of how light and temperature regulate the flowering process. We performed experiments to determine whether a 9- or 16-h photoperiod [short day (SD) or long day (LD)] before vernalization and vernalization temperatures of 8, 11, 14, 17, 20, or 23 °C under SD or LD regulate flowering of potted Miltoniopsis orchids. Flowering of Miltoniopsis Augres `Trinity' was promoted most when plants were exposed to SD and then vernalized at 11 or 14 °C. Additional experiments were performed to determine how durations of prevernalization SD and vernalization at 14 °C influenced flowering of Miltoniopsis Augres `Trinity' and Eastern Bay `Russian'. Plants were placed under SD or LD at 20 °C for 0, 4, 8, 12, or 16 weeks and then transferred to 14 °C under SD for 8 weeks. Another set of plants was placed under SD or LD at 20 °C for 8 weeks and then transferred to 14 °C with SD for 0, 3, 6, 9, or 12 weeks. After treatments, plants were grown in a common environment at 20 °C with LD. Flowering of Miltoniopsis Augres `Trinity' was most complete and uniform (≥90%) when plants were exposed to SD for 4 or 8 weeks before 8 weeks of vernalization at 14 °C. Flowering percentage of Miltoniopsis Eastern Bay `Russian' was ≥80 regardless of prevernalization photoperiod or duration. This information could be used by greenhouse growers and orchid hobbyists to more reliably induce flowering of potted Miltoniopsis orchids.
Suitability of Different Gels as Seed Carriers and Germination and Emergence Promoters in Processing Carrots
Authors: Briscoe Rowan D. , Lada Rajasekaran R. , Caldwell Claude D. , Sibley Kevin
Published: February 2019

Stand establishment is critical for optimizing yield and quality in carrots. Low soil temperatures and moisture conditions often challenge seed germination and emergence. Providing an artificial exosperm with appropriate germination promoters, stress conditioners and growth invigorators to the seed may facilitate uniform germination and emergence. Germination patterns and velocity of germination of `Oranza' carrot was studied. Seeds were mixed in different types of gels at various ratios and incubated at either 5 or 20 °C. Gels used were Laponite RD, Laponite RDS, guar gum, algenic acid, and agar. Data on germination percentage was collected and the velocity of germination was calculated. Germination was delayed at 5 °C. Both at 5 and 20 °C, Laponite RD promoted and enhanced germination and vigor, and resulted in the highest mean germination percentage (90% at 20 °C and 89% at 5 °C). Laponite RD at 2.5% has shown an overall advantage in germination percentage (94% at 20 °C and 87% at 5 °C) over other gel types and concentrations.
Planting Date and Romaine Lettuce Cultivar Affect Quality and Productivity
Authors: Dufault Robert J. , Ward Brian , Hassell Richard L.
Published: February 2019

The objective of this study was to determine the best combination of planting dates (PDs) and cultivars on yield and quality for long-term production of romaine lettuce. `Green Forest' (GF), `Apache' (AP), `Darkland' (DK), `Green Tower' (GT), `Ideal Cos' (IC), and `Tall Guzmaine' (TG) were successfully grown to harvest maturity on 19 PDs from September 1998 to April 2001. Lettuce planted in September and April PDs (pooled over cultivars and year), required as little as 47 and 49 days, respectively, to reach harvest (all cultivars harvested on the same day). Lettuce planted in October, November, February, and March PDs (pooled over cultivars and year), required on average 64, 66, 75, and 67 days to reach harvest, respectively, but in the coldest PDs of December and January, 90 and 98 days, respectively, were needed to reach maturity. Of the eight PDs evaluated, marketable numbers/plot (pooled over cultivars and years) were greatest in the September PD, followed by April (–8% decrease from September PD) > March (–13%) > October (–17%) > November (–21%) > December = January = February (about –30%) and heads weighed the most in September > January = February (–7% decrease from September PD) > March = April (–14%) > October (–21%) > December (–25%) > November (–31%). Cull heads/plot (pooled over cultivars and years) were greatest in April > December (–5% decrease from April PD) > January = February (–16%) > November (–27%) > October (–34%) > March (–44%) > September (–49%). Two out of three November PDs were lost to freezing damage and this PD should be avoided. Significant bolting occurred primarily in the September and October PDs (in 1 of 3 years) with negligible bolting in the November, December, and January PDs, but bolting recurred again in the February, March and April PDs. Marketable numbers/plot (pooled over all PDs and years) were greatest for GF > GT (–7% decrease from GF) > AP (–8%) > IC (–9%) > DK (–11%) > TG (–21%). The interaction effect of cultivar × PD indicated that GF yielded the most marketable heads in 6 out of 8 PDs. The best performing cultivars by PD (pooled over years) were September and February = GF and IC; October = TG; November = AP; December, January, March, and April = GF.
Evaluation of the USDA National Clonal Pyrus Germplasm Collection for Resistance to Podosphaera leucotricha
Authors: Serdani Maryna , Spotts Robert A. , Calabro Jill M. , Postman Joseph D. , Qu Annie P.
Published: February 2019

Powdery mildew (PM) occurs worldwide and is prevalent on susceptible cultivars wherever pears are grown, causing economic losses due to russeted fruit and an increased need for fungicides. A core subset of the Pyrus germplasm collection at the USDA National Clonal Germplasm Repository in Corvallis, Ore., was evaluated for resistance to Podosphaera leucotricha, the causal agent of PM, using greenhouse and field inoculations of potted trees. The core collection consists of about 200 cultivars and species selections, representing most of the genetic diversity of pears and includes 31 Asian cultivars (ASN), 122 European cultivars (EUR), 9 EUR × ASN hybrids and 46 pear species selections. Three trees of each core accession were grafted on seedling rootstocks. In 2001–02, trees were artificially inoculated in a greenhouse, grown under conditions conducive for PM, and evaluated for symptoms. The same trees were subsequently evaluated for PM symptoms from natural field infections during 2003 and 2004. In the greenhouse, 95% of EUR and 38% of ASN were infected with PM. Average PM incidence (percent of leaves infected) in the greenhouse (8% for ASN and 30% for EUR) was much higher than incidence in the field (2% for ASN and 5% for EUR) during 2003. Symptoms were also more severe in the greenhouse, with 46% of ASN and 83% of EUR with PM symptoms having a mean PM incidence of >10%. In the field, 42% and 22% of EUR and 23% and 13% of ASN were infected with P. leucotricha in 2003 and 2004, respectively. Field infection was very low during both years, with percentage leaves infected in ASN and species selections significantly different from EUR. In the field, 6% of ASN with PM symptoms had a mean PM incidence >10% during both years, while 15% and 2% of EUR accessions with PM symptoms had a mean PM incidence >10% in 2003 and 2004 respectively. These results should be very useful to pear breeding programs to develop improved PM resistant cultivars in the future, by using accessions with consistent low PM ratings.
Tomato Early Seedling Height Control Using a Paclobutrazol Seed Soak
Authors: Brigard Juan P. , Harkess Richard L. , Baldwin Brian S.
Published: February 2019

Tomato seedling hypocotyls elongate rapidly after germination resulting in weak seedlings. The effects of 0, 250, 500, 750, or 1000 mg paclobutrazol (PB)/L seed soak and soaking times from 1 to 12 hours on tomato (Solanum lycopersicum L.) seed germination, seedling growth, and plant growth were tested. Adequate height control was obtained with 250 mg PB/L while soaking time did not affect seedling growth. In a second experiment, PB was tested at 0, 50, 100, 150, 200, or 250 mg PB/L soaking the seed for 1 hour. A concentration of PB at 100 mg·L–1 provided optimum control of hypocotyl elongation with minimal residual effect on subsequent plant growth. In a third experiment, seed soaked at the different PB concentrations were germinated and grown under light intensities of 0.09, 50, 70, or 120 μmol·m–2·s–1. Seedlings grown under 0.09 μmol·m–2·s–1 were not affected by PB treatment and did not develop an epicotyl. PB seed soak treatment gave greater growth suppression under 50 μmol·m-2·s-1 than under the two higher light levels. Soaking tomato seeds in 100 mg PB/L for 1 hour prevented early hypocotyl stretch of tomato seedlings with no long term effects on plant growth. This treatment effectively prevented excessive hypocotyl elongation when seeds were germinated under low PAR while not over controlling elongation under high PAR conditions.
Phenolics and Carotenoids Contribute to Antioxidant Activity in Navel Orange
Authors: Jayaprakasha G.K. , Wilson Clark , Patil Bhimanagouda S.
Published: February 2019

Consumption of fruits and vegetables has been associated with reduced risk of disease, such as neurodegenerative disorders and certain forms of cancer, and aging. Antioxidants prevent the damage to macromolecules and cells by interfering with the free radicals. Several natural compounds that posses antioxidant activity have been reported from plant sources and are commercially promoted as nutraceuticals. Citrus fruits contain certain bioactive compounds such as phenolics, flavonoids, limonoids, carotenoids, and ascorbic acid. In this context, navel oranges were freeze-dried and extracted with five different solvents, such as hexane, ethyl acetate, acetone, methanol, and 8 methanol: 2 water. The extracts were dried under vacuum and screened for their radical scavenging activity using the 1,1-diphenyl-2-picrylhydrazyl method at 250, 500, and 1000 ppm. The methanol: water and methanol extracts of navel orange were found to be maximum (92.9%) and minimum (63.89%) radical scavenging activity at 1000 ppm. Furthermore, the antioxidant capacity of all extracts was assayed through the phosphomolybdenum method and expressed as equivalent to ascorbic acid (μmol/g of the extract). The order of antioxidant capacity for navel orange extracts was found to be ethyl acetate > acetone > methanol: water > methanol > hexane. It seems that the antioxidant capacity of the extracts is in accordance with the amount of phenolics/lycopene present in each fraction and may provide a good source of antioxidants. This project is based upon work supported by the USDA–CSREES under Agreement USDA IFAFS #2001-52102-02294 and USDA #2005-34402-14401 “Designing Foods for Health” through the Vegetable and Fruit Improvement Center.
Planting Date Effects on Anthocyanin Concentrations in Nine Lettuce (Lactuca sativa) Varieties and Relationships among Anthocyanin Levels and Instrumented and Visual Assessments of Color
Authors: Gazula Aparna , Kleinhenz Matthew , Ling Peter , Scheerens Joseph
Published: February 2019

Leaf samples collected from field plots of nine lettuce varieties established in the Early (ES) and Late (LS) Summer of 2002 and 2003 in Celeryville, Ohio, were subjected to spectrophotometric measurement of anthocyanin concentrations and/or color analysis based on colorimeter and spectroradiometer readings and human panelist ratings. Interactions between year (Y), planting date (PD), and variety (V) main effects for anthocyanin concentration were significant due to shifts in response magnitude, but not direction. Anthocyanin levels were higher following LS than ES planting, regardless of Y and V, and PD effects were pronounced in 2002, when differences in average daily temperature between ES and LS plantings tended to be larger. Also, regardless of Y and PD, anthocyanin levels followed the pattern `Impuls' > `OOC 1441' > `Valeria' > `OOC1426' > `Lotto' > `SVR 9634' `OOC 1434' > `OOC 1310' > `Cireo'. Treatment-based color differences were also evident in colorimeter and spectroradiometer readings. And, panelists differentiated field-grown samples based on red color intensity. Strong correlations between analytical and instrumented and human panelist-based measures suggest that instrumented assessments of red color intensity may serve as reliable proxies for direct measures of anthocyanin levels or human panelist ratings, particularly if the aim is to establish color differences between major experimental groups and assign a quantitative, repeatable value to red color intensity.
Techniques to Evaluate Caladium Cultivars for Host Resistance to Fusarium Tuber Rot
Authors: Goktepe Fahrettin , Deng Zhanao , Harbaugh Brent K. , Seijo Teresa , Peres Natalia A.
Published: February 2019

Caladiums, widely used in containers and landscapes as ornamental plants for their bright colorful leaves, are generally forced or grown from tubers. Commercial production of these tubers in central Florida is through dividing “seed” tubers and growing them in fields. Tuber quality is therefore of critical importance to success in container forcing, landscape use, and tuber production. Fusarium tuber rot (Fusarium solani) has been recognized as the most-destructive disease that affects caladium tuber quality. There is anecdotal evidence from growers indicating the existence of resistance in commercial caladium cultivars. To identify and confirm the source of fusarium tuber rot resistance in caladium, F. solani isolates have been collected from rotting tubers grown under different soil conditions and from different locations. The pathogenecity of these isolates has been tested through artificial inoculation of fresh harvested and/or stored tubers, and a number of highly virulent isolates have been identified. These isolates have been used to refine inoculation and disease evaluation techniques. Two techniques, spraying a conidial suspension onto fresh cut surfaces and inserting Fusarium-infested carnation leaf segments into artificial wounds, have proven to yield consistent resistance/susceptibility ratings among cultivars of known difference in resistance to fusarium tuber rot. Appropriate incubation temperatures and humidity seem to be very critical for disease development and evaluation. The two techniques have been used to evaluate 35 cultivars. Several cultivars, including `Candidum', showed a high level of resistance to fusarium tuber rot, and may be good breeding parent for developing new resistant cultivars.
Advanced Teacher Training on Air Pollution Effects on Plants at the Air Quality Learning and Demonstration Center at the Arboretum at Penn State
Authors: Decoteau Dennis , Ferdinand Jonathan , Savage Jim , Stevenson Dick , Davis Donald
Published: February 2019

Penn State's Air Quality Learning and Demonstration Center was completed and open to the public in 2003. The facility houses the State College air monitors for the Department of Environmental Protection and contains self-guided walkways through gardens of air pollution sensitive plants, innovative techniques for demonstrating the effects of air pollutants on plants, displays of recent research findings, industry-supported displays of pollution abatement technologies, and a teaching pavilion. One of our outreach projects, funded by the US EPA and the PA Department of Environmental Protections, is to provide enhanced teacher training on air pollution impacts on the regional and specific vegetation through an in-service training for local science school teachers utilizing on-site and archived data on weather conditions and plant injury symptom development. The picture archive began to be developed during Summer 2005 using video cameras that are permanently mounted for the growing season inside the open-top chambers and focused on a plant (and a specific leaf or set of leaves). Once the teachers are trained to utilize these data sets appropriately, they will be able to access the data during the school year through the Learning Center website and conduct the same analysis with their students in their classroom during the school year. This use of archival information is important because the school year does not coincide with optimum times for observing air pollution symptoms on vigorously growing field-grown plants in Pennsylvania (which is best during the summer).
State Partnership Program: Mississippi and Bolivia
Authors: Coker Christine E. , Evans William , Collins Michael , Blankenship Walter
Published: February 2019

The National Guard State Partnership Program seeks to link the National Guards of the United States with Ministries of Defense of emerging democratic nations in cooperative activities of mutual benefit. The Program aims to enhance those connections by bringing “Hometown America” onto the international stage through personal, sustained relationships. These associations could build a “Bridge to America,” establishing and nurturing bonds of mutual understanding at the grass roots level. The focus of the program has shifted rapidly to the “citizen” aspects of the National Guard, with instruction, orientation, and personnel exchanges in areas such as economic development, small business administration, and entrepreneurship. Mississippi's program partner is Bolivia. Mississippi State University was called upon to participate in the program by providing Subject Matter Experts. Scientists spent seven days in Bolivia working with the Bolivian military (made up of conscripted soldiers as young as 14 years of age), the Catholic University, and local villages, advising on greenhouse vegetable production and instructing program participants on cultural practices that would benefit their communities.
Growth, Flowering, and Survival of Gaillardia pulchella Foug. Based on Seed Source and Growing Location
Authors: Norcini Jeffrey G. , Danielson Helen E. , Wilson Sandra B. , Schoellhorn Rick , Miller Deborah L.
Published: February 2019

Containerized Gaillardia pulchella Foug. derived from seed of natural populations in east Texas (ET), northeast Florida (NEF), central west Florida (CWF), central east Florida (CEF), and southeast Florida (SEF) were transplanted in early April to field sites located in northwestern, northern central, and southeastern Florida. During the 22-week study, plants were irrigated only during the first 2 weeks after transplanting to aid establishment. Plant growth was assessed by calculating growth indices (GI, a gauge of plant size based on height and width) at first and second flowering peaks, and by recording shoot dry weight at first flowering peak. Growth index varied among ecotypes and sites but ecotype × site was nonsignificant. At 22 weeks, NEF and ET had GIs about 18% larger than CEF or SEF. Plants grew more at the two northern sites than in southeastern Florida, which was probably due to the loamy soils at the northern sites. Averaged over the entire study, visual ratings of vigor, flowering, and quality varied by ecotype; ecotype × site interactions were nonsignificant. All ecotypes except CEF exhibited equally high vigor, flowering, and quality. Plants in southeastern Florida had lower vigor and flowering ratings than those at the two northern sites. Survival varied by ecotype and site, and ecotype × site was significant. Within a site, survival of NEF, SEF, and ET was equally high (83% to 100%). Also, CWF had 100% survival at the two northern sites, yet no CWF plants survived past week 16 in southeastern Florida. There was no short-term home region advantage to necessitate using local G. pulchella ecotypes in residential or commercial landscapes. CEF and CWF performed poorly in southeastern Florida, which was probably related to excessive June rain.
Root Zone Temperature as Modified by Plastic Mulches Affect the Appearance of First Systemic Symptoms of Tomato Spotted Wilt and Fruit Yield in Tomato
Authors: Diaz-Perez Juan C. , Gitaitis Ron , Mandal Bikash
Published: February 2019

Tomato spotted wilt (TSW) is a serious constraint to tomato production in various regions of the world. The effect of TSW on tomato yield is largely influenced by time of infection. Early infection usually results in severe stunting of the seedling and even death of the plant. Plastic mulches have been found to affect both the incidence of TSW, and plant growth and yield of tomato. The objective of this study was to determine the effect of root zone temperature (RZT) as affected by plastic mulch on the timing of appearance of first TSW symptoms, vegetative top fresh weight (FW) and fruit FW in tomato. Under natural TSW infection as well as in artificially inoculated plants, vegetative top FW and fruit FW were both linearly related with number of days after transplanting (DAT) the plants were free from TSW symptoms. The plants grown on black mulch during the fall showed earlier appearance of TSW symptoms, and had significantly reduced vegetative growth and fruit yields. The mean RZT during the first 42 DAT—the time before the plants reached full canopy closure—significantly affected the timing of first appearance of TSW symptoms, tomato plant growth and fruit yield. Vegetative top FW (optimal RZT = 24.1 °C) and fruit FW (26.9 °C) fitted the quadratic relationships with the mean RZT during the first 42 DAT. In conclusion, utilization of plastic mulches that created conditions of RZT stress, particularly heat stress, resulted in reduced plant growth and yield and may predispose the plants to earlier expression of TSW symptoms compared to plants grown under RZTs more favorable to tomato plant growth.
Construction of Antisense ACC Oxidase Gene of Lilium and its Genetic Transformation
Authors: Liu Yali , Hao Fuling , Meng Rui , Xu Weirong
Published: February 2019

The enzyme ACC oxidase (ACO), encoded by a small multigene family in many plants, catalyzes the terminal step in the ethylene biosynthesis pathway. In this research, based on the total RNA isolated from the flowers of Asia hybrids `Pollyanna' and Oriental hybrids `Sorbonne', we obtained two cDNA fragments of ACO genes (Genbank accession DQ062133 and DQ062134) by RT-PCR technique. The two cDNA fragments were reversely inserted into plant expression vector pWR306 respectively, and constructed two antisense ACO gene expression binary vectors harboring hygromycin phosphotransferase (hptII), glucuronidase (uid A), and a green fluorescent protein (GFP) gene in the T-DNA region. We have developed a system to produce transgenic plants in LiLium via Agrobacterium tumefaciens-mediated transformation of calli. Transformants were subjected to GFP expression analysis, PCR assay, and Southern hybridization to confirm gene integration.