bluuebunny/crossref_metadata_2025 huggingface dataset:
246 Least Squares Means Comparisons for Interaction Means in a Two-factor Study in Apple Rootstock Trials
Authors: Marini Michele , Hinkelmann Klaus , Marini Richard
Published: February 2019

Trunk cross-sectional area data for an NC-140 apple rootstock trial were collected in 1998. There were 18 rootstocks and 20 states, and these factors were arranged in a factorial structure; the interaction term (variety × state) was statistically significant (P < 0.05). There were 10 trees of each rootstock planted in each state, but some trees died and this created unequal numbers of observations. Historically these data would have been analyzed using PROC GLM in SAS, correctly identifying the interaction significance, and then analyzing differences for states within a rootstock, and differences for rootstocks within a state. This analysis would not take advantage of all the replication available in the study. To more appropriately utilize the available replication, and to account for the unbalanced number of observations, a macro program was written in SAS. The slice option in PROC MIXED generates individual significance levels for the rootstock factor within a state, but does not make comparisons between rootstocks within a state. The SAS macro was written to use the individual error terms and least squares means generated from PROC MIXED to make each individual Tukey's multiple comparison between rootstocks within a state. The justification for this analytical approach, the SAS macro, and the results of the analysis will be presented.
249 Cropping Highbush Blueberry in Coal Ash-Compost Mixtures
Authors: Black Brent L. , Zimmerman Richard H.
Published: February 2019

Highbush blueberry plants require low-pH, well-drained sandy soils. To increase the range of sites available for highbush blueberry production, by-products were tested as constituents in soilless media and as soil amendments. By-products, including coal ash, municipal biosolid compost, leaf compost, and acid peat, were combined in different proportions and compared to Berryland sand (alone) and Manor clay loam (alone and compost-amended) for a total of 10 media treatments. The pH of all treatment media was adjusted to 4.5 with sulfur. One-year-old tissue-cultured plants of `Bluecrop' and `Sierra' were planted in 15-L pots containing the pH-adjusted treatment media in 1997, producing their first substantial crop in 1999. For the 1999 crop, ripe fruit was harvested at weekly intervals over 5 weeks. ANOVA for yield indicated a significant cultivar × media interaction. `Bluecrop' appeared more sensitive to media treatment as yields on Manor clay loam were 80% less than on Berryland sand. Yields of `Bluecrop' on coal ash-compost mixes were similar to that of Berryland sand, and 1:1 coal ash:compost mixes produced significantly higher yields than did the 3:1 mixes. Yield of `Sierra' on Manor clay loam was 41% less than on Berryland sand, and plants growing on soilless mixes yielded 17% to 58% more than those on Berryland sand. `Bluecrop' fruit size was greatest for Berryland sand, but did not differ significantly among coal ash-compost mixes. For all media treatments, `Sierra' fruit size was inversely correlated with yield. Fruit from `Bluecrop' plants on coal ash-compost mixes ripened slightly earlier than on Berryland sand, but ripening date of `Sierra' did not vary significantly with soil treatment. The potential for employing these by-product mixes in small-scale commercial blueberry production will be discussed.
256 Effect of Field Applications of Nonselective Postemergence Herbicides on Tulip, Narcissus, and Bulbous Iris
Authors: Miller Timothy W. , Libbey Carl R.
Published: February 2019

Tulip, narcissus, and bulbous iris are grown on about 1600 acres annually in western Washington. These bulb crops are poor competitors with winter annual weeds that continually germinate from September through July in the mild maritime climate of this region. Because they do not adequately control emerged weeds but can injure bulb crop foliage, herbicides are applied in the fall. Unfortunately, fall-applied herbicides lack the soil persistence necessary for season-long weed control. If nonselective herbicides could safely be applied after emergence of bulb foliage, emerged weeds would be killed and the application of residual herbicides delayed until spring, thus lengthening the period of weed control through bulb harvest. Glyphosate was tested for selectivity at three postemergence timings (early, middle, and late) on four cultivars each of tulip and iris and three narcissus cultivars. Middle and late glyphosate treatments caused severe injury to tulip foliage and flowers and reduced bulb count and weight, but early glyphosate did not significantly injure most varieties. Narcissus and iris were more tolerant to glyphosate than tulip, but these species also were most tolerant when glyphosate was applied early. In a separate study on iris, carfentrazone, paraquat, and glufosinate were applied postemergence at the same three timings. Glufosinate initially caused moderate injury to foliage (about 20%), but plants quickly recovered. Injury from carfentrazone and paraquat was much more severe (more than 50%), although plant recovery from carfentrazone damage was greater than from paraquat. Bulb yield was not adversely affected by either glufosinate or carfentrazone if applied early. Paraquat at all timings significantly reduced total bulb count and weight.
258 Organic Media Alternatives to Peat for Container-grown Tropical Perennial Production
Authors: Wilson Sandra B. , Stoffella Peter J.
Published: February 2019

Peat is used extensively in the nursery industry as a primary component in commercial “soilless” potting media. The increased use of peat as an organic amendment with superior water-holding capacity is challenged by economic and environmental pressures. Developing inexpensive and nutrient-rich organic media alternatives can potentially reduce fertilization rates, irrigation rates, and ultimately, nursery costs. In addition, controversy over the effects of peat mining has inspired a national search for peat substitutes. With our burgeoning population, it is logical to screen waste products as potential alternatives to peat. Growth of Pachystachys lutea Nees. (Golden Shrimp Plant) transplants was evaluated in media containing 0%, 25%, 50%, 75%, or 100% compost derived from biosolids and yard trimmings. Compost was amended with a commercial peat- or coir-based media. As compost composition in the peat or coir-based media increased from 0% to 100%, carbon/nitrogen (C/N) ratios decreased, and media stability, N mobilization, pH, and electrical conductivity (EC) increased. Bulk density, particle density, air-filled porosity, container capacity, and total porosity increased as more compost was added to either peat- or coir-based media. Plants grown in media with high volumes of compost (75 or 100%) had reduced leaf area and reduced shoot and root DW than the controls (no compost). Regardless of percentage of compost composition in either peat or coir-based media, all plants were considered marketable after 8 weeks.
259 Effect of Photoperiod on Growth and Flowering of Ornamental Ginger Species
Authors: Sarmiento Mauricio José , Kuehny Jeff S.
Published: February 2019

Gingers are tropical perennials from the Zingiberaceae family with attractive long-lived flowers that can be grown as potted plants in subtropical and temperate zones under protected conditions. Development of production practices for this new flowering pot crop is essential for optimum plant growth. The effect of photoperiod on growth and flowering was evaluated on Curcuma gracillima, C. cordata, C. alismatifolia, C. petiolata `Emperor', Curcuma `Chang Mai dwarf', Siphonichilus decora, and S. kirkii. Plants were grown under daylengths of 8, 12, 16, and 20 h. Plant height, number of new leaves, number of shoots, and leaf area were larger for plants growing under an extended daylength (16- and 20-h photo-period) than for plants under 8 and 12 h. Plants grown under an 8-h daylength approached dormancy sooner than those growing under 12, 16, or 20 h of light, and no flowering occurred.
265 Influence of Frozen-in Storage Duration and Forcing Temperature on Flowering of Oriental Hybrid Lilies
Authors: Lee Jong Suk , Roh Mark S.
Published: February 2019

The effect of long-term storage of lily bulbs at -2 °C and of high temperatures on plant height and floral abnormalities was investigated with Oriental hybrid lilies in 1997-2000. `Acapulco' and `Simplon' bulbs were stored frozen at -2 °C and forced in regular greenhouses with varying temperatures between 12 to 30 °C, depending on the season, and also air-conditioned greenhouses where temperatures were maintained year-round at 15.5 to 16 °C or 18 to 18.5 °C. Floral development was observed under a scanning electron microscope after -2 °C treatment. At flowering, stem length with dried and green leaves, number of leaves, and number of normal and abnormal flowers were counted. Although frozen-in storage duration affected plant height, flowering, and the number of abnormal flowers, high temperatures during summer significantly affected the speed of flowering, plant height, and the number of abnormal flowers. High temperature damage can be prevented by growing bulbs at low temperatures immediately after planting the frozen-in stored bulbs. Bulbs can be stored for 12 months to produce quality cut Oriental hybrid lily flowers.
268 Effect of Temperature on Micropropagated Apple Plants as a Way to Overcome Plant Growth Cessation During Acclimatization
Authors: Pereira Jonny E. Scherwinski , de L. Fortes Gerson R.
Published: February 2019

The present work aimed to evaluate the plant growth of the apple rootstock Marubakaido during the acclimatization process, after receiving different treatments of temperatures. Apple shoots were rooted in vitro and transplanted to greenhouse, where they remained for 2 weeks. After this period, the plants were treated under temperature of 4 ± 1 °C and 10 ± 1 °C, 16-h photoperiod at 5μmol·m-2·s-1 radiation for 0; 360, 720, 1080, and 1440 h. The plants were transferred to the greenhouse where their growth internode length and bud number were evaluated during 2 months. It was verified that there was an increase up to 697% in the height of the plants when they were treated for 1440 h, independently of the temperature. The internode length was also larger when the plants were treated for greater periods. The temperature of 10 ± 1 °C led to a decrease in the bud number, while at 4 ± 1 °C, significant differences were not observed. These results suggest that the use of higher temperatures (10 ± 1 °C), can also recover the plant growth during the acclimatization process.
270 Effects of Chemical Thinners on Yield, Fruit Size, and Fruit Quality of `Honeycrisp' Apple
Authors: Schupp J.R.
Published: February 2019

Effects of chemical thinners on yield, fruit size, and fruit quality was studied in a commercial orchard in Milton, N.Y., on 6-year-old `Honeycrisp'/M.26 trees. The trees were planted at 1.8 × 3.6-m spacing with trickle irrigation and were trained to the vertical axis system. The treatments applied in a randomized complete-block design with four replications were an untreated control; carbaryl (Sevin XLR at 125 mL/100 L); NAA at 2.5 ppm, 5 ppm, or 7.5 ppm; NAA at 2.5 or 5 ppm plus carbaryl; and Accel (a.i. at 74 g·ha-1) plus carbaryl. Chemical thinners were applied to drip with an air-blast sprayer, when the largest fruit were 11.5 mm in diameter. Generally, thinning activity increased with increasing NAA concentration. The combination sprays of 5 ppm NAA plus carbaryl, and Accel plus carbaryl over-thinned `Honeycrisp'. Carbaryl alone was inconsistent. All thinning treatments increased fruit size relative to unthinned trees, with average fruit diameter exceeding 76 mm. `Honeycrisp' is a large-fruited cultivar that is easy to thin chemically at the traditional 10- to 12-mm growth stage. NAA at 2.5 or 5 ppm provided adequate thinning to produce fruit of good quality and size. If initial set is heavy and a stronger thinning response is desired, the combination of 2.5 ppm NAA plus carbaryl could be used. `Honeycrisp' appears to be very sensitive to Accel, when used in combination with Sevin XLR. Further research needed before Accel is used to thin `Honeycrisp'.
272 Chemical-thinning Asian Pears
Authors: Prunty Regina M. , Marini Richard P.
Published: February 2019

Asian pears bloom profusely and require early hand-thinning to produce large saleable fruit. In 1998, `Shinko' and `Hosui' trees were sprayed with Accel, Ethrel, NAA or carbaryl when average fruit diameter was ≈9 mm. Superior oil was added to all treatments at the rate of 2.5 mL/L. Fruit set was reduced 40 to 70% by Accel at 84 ppm and ethephon at 678 ppm, but NAA at 8 ppm and carbaryl were less effective. In 1999, Accel was applied at a range of 0 to 105 ppm and ethephon was applied at a range of 0 to 678 ppm. All treatments contained carbaryl and oil. Fruit set/100 flower clusters declined linearly with increasing ethephon concentration on `Shinko', but was not tested on `Hosui'. Fruit/100 blossom clusters declined linearly with increasing Accel concentration on `Shinko'. On `Hosui' Accel reduced fruit set by more than 40%, but treatments did not differ significantly (5% level) from the control. In both years `Shinko' was easier to thin than `Hosui'.
274 Peach Floral Budbreak as Affected by Foliar Nitrogen Sprays and Girdling
Authors: Sanchez-Urdaneta Adriana Beatriz , Cano-Medrano Raquel , Rodrl̀guez-Alcazar Jorge
Published: February 2019

The purpose of this research was to investigate the effect of 1% N foliar sprays (0, 2, and 4 sprays at weekly intervals) and girdling (G) on budbreak of three peach advanced selections CP95-1 °C, CP91-8, and CP91-17, and its relationship with both reduced nitrogen (RN) and polyamine contents. Foliar N was applied in July, before flower initiation was detected and girdling was performed 30 days after nitrogen sprays (DAT) The results indicate that 4N+G treatment had the highest content of (RN) with values between 232 and 1000 mg N/g of DW. CP 91-17 and CP95-1 °C selections showed higher RN content than that of CP91-8. Both 2N+G and 4 N+G showed the highest content of putrescine (Put) (908 and 1635 nmol·g-1 FW, respectively). Among peach selections CP91-8 was the one with the highest content of Put. Putrescine content went down as the flower differentiation process evolved. Four N+G treatment promoted budbreak in CP95-1 °C advancing it in 55 days as compared to the control. Budbreak began earlier in the three peach selections treated with 4N+G (11/12/98) followed by 2N+G treatment (7/001/99), and the control (4/02/99). Fruit set was 19%, 12%, and 11% for 4N+G, 2N+G, and control treatments, respectively.
275 Effect of Fruit Quality, Ethylene Evolution, and Storage in Apple `Tsugaru' as Influenced by Aminoethoxyvinylglycine and Several Surfactants
Authors: Kang Chung-Kil
Published: February 2019

This experiment was conducted to evaluate the effect of fruit quality, ethylene evolution, and storage in apple `Tsugaru' as influenced by aminoethoxyvinylglycine (AVG) and several surfactants. When treated with AVG + Silwet L-77, there was little significant difference in soluble solids and acidity as compared with control, but dichlorprop treatment was significantly increased in soluble solids and decreased in acidity. Color development was decreased when treated with AVG + Silwet L-77. AVG + Silwet L-77 treatment decreased ethylene evolution, and increased storage. It can be concluded that fruit can be left on trees longer and still maintain storability, and more fruit is able to go to fresh market from long-term storage, which increases the marketability of apple.
276 Fall Ethephon Applications Delay Bloom of `Climax' Blueberry
Authors: Krewer Gerard , NeSmith D. Scott , Mullinix Ben
Published: February 2019

`Climax' blueberry is a major cultivar in Georgia, but because of its excessively low chilling requirement and early blooming habit, it has a poor cropping history in recent years due to spring freezes. Research was initiated to explore the potential for ethephon to delay bloom, without delaying ripening too much. In 1997-1998 a treatment of 200 ppm ethephon applied on 3 Nov. or 400 ppm applied on 17 Nov. delayed bloom 5 to 7 days compared to the control. There was no significant difference between the control and the ethephon treatment in flower bud density or fruit density in the spring. In 1998-1999 ethephon applications at 200 and 400 ppm were applied once or twice 2 weeks apart starting on 5 Oct. and ending 19 Nov. A bloom delay of about 7 days was achieved with most ethephon applications. However, an application of 400 ppm on 19 Oct. and 2 Nov. delayed bloom about 14 days compared to the control. There was a trend toward delayed fruit ripening with the most-effective bloom delay treatments, but the extent of delayed ripening was minimal. Berry weight was not effected by ethephon treatments.
278 A Ratoon Cropping System for Fall Bell Pepper Production
Authors: Kahn Brian A. , Leskovar Daniel I.
Published: February 2019

Studies were conducted to examine the effects of pruning treatments applied to spring-transplanted bell peppers (Capsicum annuum L.) on marketable fruit yield in late summer and fall. Control plants were set in the field in early May 1997 (Oklahoma) and Apr. 1998 (Oklahoma and Texas) and were harvested weekly into October (Oklahoma) or periodically into December (Texas). In 1997, there were no differences in total marketable fruit weight among four treatments involving height and method of pruning, but all reduced total marketable fruit weight relative to the control. In Oklahoma in 1998, the control was compared to plants mowed on 27 July at an average height of ≈24 cm. Mowed plants produced less total marketable fruit weight but more U.S. Fancy fruit than control plants. Also, control and mowed plants did not differ in weight of U.S. no. 1 fruit. In Texas in 1998, the control was compared to plants mowed on 4 Sept. at a height of ≈20 cm. Mowed plants produced more than double the weight of U.S. no. 1 fruit and fewer cull fruit than control plants. Nonpruned transplants set in the field in Summer 1998 (Oklahoma and Texas) gave low marketable yields. Maintaining spring-transplanted bell peppers is a viable technique for fall pepper production, and the highest total marketable yields may occur if these plants are not mowed. However, mowing offers an opportunity for increased fall production of premium fruit, and mowed plants would be easier to manage than unpruned plants.
282 Vegetable Yields under Sustainable Production Systems
Authors: Hoyt G.D. , Walgenbach J.E. , Shoemaker P.B.
Published: February 2019

This experiment was designed to compare best management practices for conventional and conservation tillage systems, chemical IPM vs. organic vegetable production, and rotation effect on tomatoes. Three vegetables were grown under these management practices with sweet corn (1st year) and fall cabbage or cucumber (2nd year), and fall cabbage on half of the field plots and tomatoes on the other half. The treatments were: 1) conventional-tillage with chemical-based IPM; 2) conventional-tillage with organic-based IPM; 3) conservation-tillage with chemical-based IPM; 4) conservation-tillage with organic-based IPM; and 5) conventional-tillage with no fertilizer or pest management (control). This poster describes sweet corn, cabbage, and cucumber yields from the various treatments over two 3-year rotations. Sweet corn yields were 34% higher in treatments with chemical fertilizer and pest control than with organic methods. Ear worm damage was high (58%) in the organic treatment compared to the chemical IPM program (14%). Fall cabbage was planted after sweet corn and cucumber harvest (all treatments were reapplied). Marketable cabbage yields were in the order: conventional-tilled-organic > strip-tilled-chemical > conventional-tilled-chemical > strip-till-organic > control for both years. Percent culls (< .9 kg heads) were in reverse order of marketable heads. Cabbage insect control was similar in chemical IPM and organic management. Cucumber yields were in the order: conventional-tilled-chemical > conventional-tilled-organic = strip-till-chemical > strip-tilled-organic > control for both years. Insect damage on cucumber fruit was 51% for organic systems and 1% for chemical methods of production. No differences were seen between tillage system within the same production system (chemical vs organic).
284 Comparison of High- and Low-input Production Schemes in Pumpkins
Authors: Precheur Robert J. , Bergefurd Brad , Harker Thom , Riedel Richard M. , Welty Celeste
Published: February 2019

Pumpkins are Ohio's third-largest fresh-market vegetable crop. Many non-traditional growers are planting pumpkins to increase gross income. Experienced growers have noticed that new producers are successful with low input. Are intensive production practices needed for a good crop? High and low input production schemes were studied, over 3 years on pumpkin yield and quality. High input consisted of Furadan at planting, reflective mulch, trickle irrigation, and a routine fungicide and insecticide spray program. Low input consisted of no mulch, no supplemental irrigation, and a reduced fungicide and insecticide program. The number of insecticide plus fungicide sprays for high vs. low input were: 10 vs. 5 in year 1; 5 vs. 3 in year 2; and 12 vs. 8 in year 3. Number and weight of marketable orange fruit in high-input plots were significantly higher than low input plots in year 1 and 3. Plastic mulch conserved soil moisture and resulted in 91% plant stand in high input vs. 57% in low input in year 1. The only year without a significant yield difference was when the difference in pesticide sprays was two. High input is suited for retail markets where the expectation is good yields of high quality pumpkins. Wholesale producers can probably get by with reduced inputs in certain areas.
290 Potassium Fertilizer and Soil Nutrient Status Affect Internal White Tissue Severity and Influence Fruit Quality in Ohio Processing Tomatoes
Authors: Evans William B. , Bennett Mark A.
Published: February 2019

A significant portion of the Great Lakes region's processing tomato crop is used to make whole fruit and diced products, where fruit color and textural uniformity are important. Soil and fertilizer studies were undertaken to better understand the role of soil fertility and potassium application on the color disorder known as internal white tissue (IWT) under this region's conditions and in area soils. During 2 years of replicated potassium rate trials in Ohio, tomato yield was not significantly altered by broadcast potassium applications. Potassium application rate was inversely correlated with frequency and severity of IWT in each season, and positively correlated with titratable acidity. The ability of split applications to influence IWT severity was not significantly different than that of preplant applications. IWT symptom frequency and severity was correlated with elemental concentrations in the fruit, leaves, and soil. In 1998, severity of IWT symptoms was positively correlated with shoulder tissue calcium and sodium concentrations, and negatively correlated with concentrations of phosphorus, magnesium, and nitrogen. Correlations for other nutrients, including potassium, were less clear. A companion study of six grower fields during the second year, using grid sampling techniques and the IWT-susceptible Peto 696 cultivar, found significant variability of IWT symptoms within and among fields. Variability within fields was correlated with soil nutrient concentrations. These data indicate researchers may be able to develop recommendations for field mapping and precision management strategies that can reduce the levels of IWT for area growers.
293 Potential Allelopathy of Sorghum-Sudan Mulch
Authors: Mitchell J.P. , Summers C. , Prather T.S. , Stapleton J. , Roche L.M.
Published: February 2019

Observations that tomato transplants died or were severely stunted when set into unincorporated sorghum-sudan hybrid surface mulch led us to further investigate the potential allelopathic impacts of this warm-season cover crop in a series of field experiments. Survival and dry weights of tomato, lettuce, and broccoli transplants were determined in fallow, incorporated sorghum-sudan-, and unincorporated sorghum-sudan-mulched soils. All three species transplanted into plots in which the sorghum-sudan had been cut and left on the soil surface had a significantly lower dry weight than plants transplanted into fallow soil or into soil where the sorghum-sudan had been incorporated. Additionally, fewer transplants survived in the mulch treatment. The surface mulch plots also significantly reduced weed biomass nearly 10-fold. We believe that a water-soluble compound that is leached out of the sorghum-sudan hybrid is toxic to all three of the plants tested. Further laboratory and greenhouse tests are under way to determine the exact nature of the toxic substance.
294 Comparative Studies of Local vs. Imported Tomato Cultivars under Saline Irrigation Water
Authors: Albaho M.S. , Eshwarib O.A.
Published: February 2019

Scarcity and high cost of good-quality water for irrigation in the Kuwait environment, which is located in an extremely arid region, necessitate the utilization of underground brackish water. However, productivity of most vegetable crops is reduced tremendously when irrigated with such low-quality water. Consequently, a tomato-breeding program had been launched to develop tomato cultivars that are well-adapted to the local conditions. The present work is a 2-year field study to compare the performance of four locally developed vs. eight imported tomato cultivars under saline irrigation water (brackish). The experiment was laid out in a completely randomized block design with four replications. Dimensions of each experimental unit was 2 × 2.5 m (5 m2). Fertilization and other cultural practices followed those recommended for the local environment and soil was sandy in texture. Prior to transplanting seedlings to field, they had been irrigated with nonsaline water. Total dissolved solutes of the brackish water used for irrigation was 7500 mg.L-1. A total of seven harvests were collected on a weekly basis. There were no significant differences among tomato cultivars in terms of total fruit weights in the first four harvests. However, beginning with the fifth harvest, two of the locally developed cultivars (Kuwait-16 and Kuwait-20) were among the highest in total yield for two consecutive years in this study. It is therefore recommended that these Kuwaiti tomato cultivars be used to replace the several expensively imported varieties, which, though high yielding, are not necessarily so in the Kuwait environment, or may be salt-sensitive cultivars. Combining the local varieties with the use of less expensive brackish water could reduce the expense of farming significantly in this region of the world.
295 Controlling Crop Growth Media Moisture with Sensors
Authors: Monje O. , Goins G.D. , Levine H.G. , Stutte G.W.
Published: February 2019

Tight control of growth media moisture content is needed when plant growth systems employ shallow root zones or for cultivating fast-growing plants (i.e., crops). Poor control of moisture can affect both growth rate and plant quality by either excessive watering (waterlogging) or drought events. We evaluated the performance of two types of moisture sensors: tensiometers and heat-pulse moisture sensors. The output from each sensor type was evaluated as a function of volumetric moisture content in 1 to 2 mm Turface. The tensiometers were more sensitive between 30% and 60% volumetric moisture content, and their output was nonlinear because they measure water potential directly. In contrast, both the sensitivity and the output of the heat-pulse moisture sensors, as a function of volumetric moisture content, were linear. The heat-pulse moisture sensors were used to control moisture content in a shallow root zone, whereby water was added or removed from the media through a porous tube using peristaltic pumps. Moisture content in the media could be maintained within ±2% of setpoint for moisture contents ranging from 20% to 100% volumetric moisture content. The heat-pulse sensors were better suited for controlling media moisture because of their linear output and because of their constant sensitivity as a function of volumetric moisture content.
299 Effects of Plant Growth Regulators on Heat Stress in Annual Artichoke Production
Authors: Schrader Wayne L.
Published: February 2019

Artichoke is a cool-season perennial crop that is grown as an annual from seed in southern California. Growing artichokes as annuals from seed allows growers to harvest during the winter from November to March. Artichoke seed is planted in May, transplants are moved to the field in July, and harvesting begins as early as November in years with relatively cool fall weather. Hot fall weather during September and October suppresses plant growth and causes premature flowering, which lowers yield and average bud size. Plant growth regulator (PGR) treatments were evaluated in annual artichokes to determine if they could reduce the adverse effects of hot weather during September and October. Treatments included multiple applications of apogee (gibberellin inhibitor), retain (ethylene inhibitor), apogee + retain, cytokinin, and control plots. Harvestable buds were counted as a measure of earlier flowering induced by hot weather. Apogee and cytokinin show promise in reducing heat stress during hot fall artichoke production. Other PGR treatments increased the number of harvestable buds compared to control plots.
300 Effects of Plant Growth Regulators on Eggplant (Solanum melongena L.) Yield
Authors: Morales-Payan J. Pablo
Published: February 2019

Field studies were conducted in the Dominican Republic to determine the effect of several plant growth regulators on the yield of `Jira' eggplant. Treatments consisted of aqueous solutions of folcysteine (25, 50, 75 ppm), giberellic acid 3 (10, 20, 30 ppm), kinetine (25, 50, 75 ppm), naphthalenacetic acid (NAA) (25, 50, 75 ppm), 2,3,4-dichloro-phenoxy-triethyl-amine hydrochloride (DCPTA) (25, 50, 75 ppm), triacontanol (5, 10, 15 ppm), ethanol (5, 10, 15%), and chlormequat (50, 100, 150 ppm) sprayed at early flowering, directed to the crop upper leaves and flowers. A control treatment (no plant growth regulators applied) was also included. A randomized complete-block design with four replications was utilized. Experimental units were two rows of 10 plants at a 1.0 × 0.4-m distancing. Eggplant fruit set and yield were determined after 10 harvests performed at 3-day intervals. Analysis of variance and mean comparison tests were performed on the resulting data. `Jira' eggplant fruit set and yield was significantly improved by folcysteine, giberellic acid 3, and NAA, but not by kinetine, DCPTA, ethanol, triacontanol, or chlormequat. Eggplant yield increased as folcysteine rate increased from 0 to 50 ppm, but no further yield increase was obtained when increasing the rate from 50 to 75 ppm. Similarly, eggplant yield significantly increased as gibberellic acid increased from 0 to 20 ppm, but not when rates increased from 20 to 30 ppm. With NAA, eggplant fruit set and yield significantly increased above that of control plants when 25 ppm was applied, with no significant yield increase at higher rates. Results indicate that the yield of `Jira' eggplants could be enhanced by the treatments with either folcysteine, NAA, or gibberellic acid hereby described.
301 Gibberellic Acid (GA3) and Light Affect Germination of Echinacea angustifolia Seeds
Authors: Cho Keun Ho , Lee Chiwon W. , Lee Kyu-Min
Published: February 2019

The narrow-leaved purple coneflower (Echinacea angustifolia) produces echinacin and related compounds in the root, which are known to have immune and curative properties against viral, fungal, and bacterial infections. In recent years, cultivation of this species has increased in response to growing market demand for natural medicinal remedies. The objective of this study was to determine the influence of gibberellic acid and light on the germination of E. angustifolia seeds. Seeds soaked for 24 h in 0, 1, 5, 10, 50, 100, 250, 500 or 1000 mg/L GA3 solution were germinated on Whatman #1 filter paper inside petri dishes at 22 °C with or without light (80 μmol·m-2·s-1) for 21 days. The seeds germinated poorly in dark with the final percent germination range from 10% (GA3 1000 mg/L) to 36% (GA3 250 mg/L). Under light, seed germination showed a quadratic response (r = 0.84) to GA3 concentration. Percent germination exceeded 90% at 10, 50, and 100 mg/L GA3 with the mean time (T50) to germinate varying at 10.5, 11.7, and 13.3 days, respectively, under light. Seed germination under light was <10% when treated with 500 and 1000 mg/L GA3. In general, seed germination was best when treated with 10 or 50 mg/L GA3 under light. Results of this research may well be used in enhancing seed germination during field establishment of E. angustifolia.
303 Pre-sidedress Soil Nitrate Concentrations and Yield Response to Fertilizer Applications in Processing Tomatoes
Authors: Krusekopf H.H. , Mitchell J.P. , Hartz T.K. , May D.M. , Miyao E.M. , Cahn M.D.
Published: February 2019

Overuse of chemical N fertilizers has been linked to nitrate contamination of both surface and ground water. Excessive fertilizer use is also an economic loss to the farmer. Typical N application rates for processing tomato production in California's Central Valley are 150-250 kg·ha-1, and growers generally fail to fully consider the field-specific effects of residual soil NO3-N concentration, or N mineralization potential of the soil. The purpose of this research was to determine the effects of sidedress N fertilizer application, residual soil NO3-N, and in-season N mineralization, on processing tomato yield. Research was conducted during the 1998 and 1999 growing seasons at 16 field sites. Pre-sidedress soil nitrate concentration was determined at each trial site to a depth of 1 m, and aerobic incubation tests were conducted on these soils (top 0.3 m depth) to estimate N mineralization rate. Sidedress fertilizer was applied at six incremental rates from 0 to 280 kg N/ha, with six replications of each treatment per field. Only five fields showed yield response to fertilizer application; yield response to fertilizer was associated with lower pre-sidedress soil nitrate levels. In most fields with fertilizer response, yield was not increased with sidedress N application above 56 kg·ha-1. Mineralization was estimated to contribute an average of ≈60 kg N/ha between sidedressing and harvest. These results suggest that N fertilizer inputs could be reduced substantially below current industry norms without lowering yields, especially in fields with higher residual soil nitrate levels.
306 Preharvest Methods to Reduce Skinning in `Beauregard' Sweetpotato
Authors: Schultheis Jonathan R. , Blankenship Sylvia M. , Monks David W. , Boyette Michael D.
Published: February 2019

The `Beauregard' sweetpotato variety is very prone to damage to its skin. We evaluated several preharvest treatments to reduce skinning so that less damage was done at harvest, during transport, and packing. Three field tests were conducted in 1998 (two tests) and 1999 (one test) in North Carolina. Treatments were implemented 1 and 2 weeks prior to harvest and were either chemical or mechanical. The three mechanical treatments were flail mowing, flail mowing and barring off, and vine snatching. The following chemical treatments were made: PREP, Diquat, Dessicate II, and 2,4-D at various rates. Sweetpotatoes were harvested and roots were graded. Subsequently, U.S. No. 1 root subsamples were obtained from each plot in order to evaluate the effects of treatment on skin tightening of roots. Roots were evaluated from each plot for skin toughness using a “skin-o-meter” where a pressurized stream of water was directed at a sweetpotato. The roots were then evaluated for skinning by checking if the skin was broken using the skin-o-meter. A second method was used to evaluate the effect of treatment for its effect on skin tightening (reduced skinning). One bushel of roots from each treatment plot was transported to Clinton, N.C., and run through a small packing line at the Horticultural Crops Research Station the next day after harvest. The sweetpotatoes were then evaluated in Raleigh for the number of incidences where skin had been removed during the harvesting, transport, or packing process. The severity of skinning was characterized by counting the number of small (<5 mm), medium (width 5-10 mm) and large (width 10+ mm) skinned areas on a root. An overall appearance rating for roots was also recorded for each subsampled plot with 10 being the best rating and 1 being the worst. Results indicate that treatment 14 days prior to harvest rather than 7 days prior to harvest seems to be advantageous in most cases for reducing skinning and maintaining yield of sweetpotato when compared with not treating the vines. Regardless of whether the treatment was chemical or mechanical, treatments were apparently beneficial in these tests. Application of PREP 7 days prior to harvest resulted in sweetpotatoes with the most resistance to skinning in 1999, the fewest large-size skinning abrasions on roots, and best appearance. PREP shows promise as a means to reduce skinning in sweetpotatoes, but presently is not labeled for use on sweetpotatoes.
307 Growth Regulator Pretreatments Significantly Enhance the Efficiency of Shoot Organogenesis from Leaf Explants of Highbush Blueberry Cultivar Bluecrop
Authors: Cao X. , Hammerschlag F.
Published: February 2019

As part of a program to develop transgenic highbush blueberry (Vaccinium corymbosum L.) cultivars, studies were conducted to determine optimum conditions for high-efficiency shoot regeneration from leaf explants of in vitro propagated, commercially important, tissue culture-recalcitrant `Bluecrop' shoot cultures. The effects of pretreatments, growth regulators, and age of explant source on shoot organogenesis were investigated. A maximum of 98% shoot regeneration and 10 shoots regenerating per leaf explant occurred when explants of 2-week-old shoot cultures were incubated in the dark (for a total of 14 days) on pretreatment medium #1 containing 2.6 μM NAA and 5 μM TDZ for 4 days, next on pretreatment medium #2 containing 2.6 μM NAA and 7 μM zeatin riboside for 3 days, then on regeneration medium containing 1 μM TDZ for 6 weeks, and last on medium without growth regulators for 10 days. No shoot regeneration occurred if explants were incubated without exposure to pretreatments before incubation on regeneration medium. There were no significant differences in percentage of regeneration or the number of shoots regenerating per explant from leaf explants derived from either 1-, 2-, or 3-week-old shoot cultures. Shoot production per explant on 1 μM TDZ was about three times that on either 0.5 μM TDZ or 20 μM zeatin riboside, and nine times that on 5 μM TDZ.
311 Seed Treatments, Rootstock Cultivar, and Environment Affect Peach Seed Germination
Authors: Reighard Gregory L. , Ouellette David , Brock Kathy , Newall William
Published: February 2019

Poor peach seed germination can be a problem for commercial tree fruit nurseries. Even standard rootstocks such as Lovell and Nemaguard do not always have high germination rates. New seed-propagated rootstocks under development, such as Guardian peach rootstock, often are selected for their field traits, with nursery characteristics being of secondary importance. Guardian rootstock is derived from bulked open-pollinated seed from a number of F1 seedling selections. Germination of Guardian bulked seed has been poor. Four pre-stratification cold treatments were given to four 100-seed lots each of Lovell, Nemaguard, and 10 Guardian selections prior to planting each year (1994 to 1998) in a Cecil sandy loam at Musser Fruit Research Center near Clemson, S.C. Treatments included taking dry, refrigerated seed that were harvested in August and soaking 100-seed seedlots in 1500 mL perlite and 400 mL distilled water for 0 (no soaking), 2, 4, 6, and 8 weeks at 6 °C before sowing (typically early November). All treatments consisted of 25 seeds per replicate (4 reps/year) per rootstock or selection and were sowed the same day. The experiment was analyzed as a blocked split plot design with duration of stratification the whole-plot and seedlot the sub-plot. Number of emerged seedlings were counted weekly starting in January of each year. There were significant differences between stratification treatments, seedlots and years. The 6-week pre-stratification had the highest germination over 5 years and like the 8-week treatment advanced the average germination date by 20 to 30 days. Nemaguard (65%), Lovell (64%), and Guardian 3-17-7 (60%) had the best germination percent across all treatments and years, with SL2891 (42%) slightly less. All other selections averaged less than 25%. Year-to-year variation was large, indicating strong environmental influences on seed germination despite the pre-stratification treatments.
315 Alstroemeria Plants Free of Alstroemeria Mosaic Potyvirus (AIMN) through in Vitro Culture Shoots and Thermotherapy
Authors: Cervantes-Dl̀az Lourdes , Zavaleta-Mejl̀a Emma , Gutièrrez-Espinosa Alejandra , Santizo-Rincan J. Antonio
Published: February 2019

Alstroemeria (Alstroemeria spp.) is cultivated for cut flowers. Traditional propagation methods are by division of rhizomes from mature plants, so that viruses occurring in the crop can be multiplied and cause a decrease in the quality and production. The objective of this work was to obtain Alstroemeria cv. Rosario plants free of Alstromeria Mosaic Potyvirus (AlMV) by in vitro culture of shoots and thermotherapy. The best percentage of explants without contamination was obtained when adding the disinfectant PPM (1%) to the medium Murashige-Skoog (MS) while the best induction of buds was obtained when using explants of 1.5 cm. in length. In vitro multiplication of shoots was best in treatments with 2iP (isopentenyl adenine), BA (benzyladenine), and zeatin (4.4, 6.1, and 6.6 buds per explant, respectively). Rhizogenesis was observed in rhizomes growing in MS with 4.9 μM AIB (indole butyric acid) and 1.5 g·L-1 of sugar. Sixty-seven percent of plants growing in vitro did not react to AlMV antiserum and did not show particles and viral inclusions. Thermotherapy treatments of 45, 50, and 55 °C during different periods of time produced from 25% to 87.5% of plants that did not react to AlMV antiserum and did not show virus particles or cytoplasmic inclusions.
317 Establishment and Multiplication of in Vitro Pyrus spp. Cultivars
Authors: de Mesquita Dantas Adriana Cibele , Nesi Adriano Nunes , Machado Lilia Bender , Haerter Janny , de Luces Fortes Gerson Renan
Published: February 2019

The culture of meristems, shoot tips, and axillary buds leads to the method of in vitro multiplication that is easily used and safe to obtain uniform copies with no undesirable variations. This work aimed to propagate five in vitro pear cultivars: Housui, Carrick, Nijisseiki, Packham's Triumph, and Red Bartlett. The work was carried out in the Tissue Culture Laboratory at Embrapa Temperate Climate. The plants were sprayed with benomyl (1.0 mg./L) and agrimicine (2.4 mg/L) in the fields, 2 weeks before the shoots were collected. The shoots were then cut with two buds with no leaves and desinfested with alcohol 70% for 10 s and 1% sodium hypochloride for 20 min, 50 explants, 25 buds, and 25 meristems, were then transferred to test tubes containing MS salts and vitamins, myo-inositol (100.0 mg/L), sucrose (30.0 g/L), agar (6.0 g/L), added to in mg/L: BAP (1.0), GA3 (0.1), and NAA (0.01). Three pear cultivars were used for in vitro multiplication (`Nijisseiki', `Red Bartlett', and `Housui') by using the same basal salt with N reduced to strength, added to (in mg/L): BAP (1.6), NAA (0.16). The material was kept in growth room under 16-h photoperiod, 25 ± 2 °C and 19 μMol·m-2·s-1 of flux radiation. The in vitro contaminations were mainly due to bacteria derived from the bud material (71.5%). Higher oxidation for meristem material was observed for `Carrick' and `Packham`s Triumph'. `Red Bartlett' showed the best results for all the variable studied, although all cultivars in general presented low response.
318 Vermicompost Enhances Germination in Low-viability Echinacea purpurea Seed
Authors: Wills Sara Michele , Bachman Gary R.
Published: February 2019

Vermicompost or worm-worked wastes have been reported to enhance seedling germination and growth during plug production. The objective of this project was to examine the effects of vermicompost on germination of a herbaceous perennial having varying viability in coir-based container media. Seeds of Echinacea purpurea (Purple Coneflower) collected from field-grown plants in 1998 and 1999 were considered low- and medium-viability seeds, respectively. A third group of seeds was purchased from a major seed company and was considered to have high viability due to optimal storage conditions. “Ragdoll” germination tests resulted in the following viability ratings: low (1%), 1998; medium (67%), 1999; and high (79%), purchased seed. The three sources of seed were planted into coir-based media. Vermicompost was incorporated into the media at 10% by volume. The control media did not have vermicompost added. Twelve days after project initiation seeds sown into media containing vermicompost had 73% and 90% greater germination than control media for the 1999 and purchased seed. At the project conclusion, 24 days after initiation, seeds sown into media containing vermicompost had 23% and 42% greater germination than the controls for the 1999 and purchased seed. The 1998 seed had 5% germination after 24 days compared to 1% for the control. The addition of vermicompost could be used as a method to increase germination rate and percentage of seeds having lower viability.
321 Conservation of an Endangered Virgin Islands Orchid Species through Tissue Culture
Authors: Zimmerman Thomas W. , Kowalski Jacqueline
Published: February 2019

The Sandy Point Orchid (Psychilis macconelliae) is listed as an endangered orchid species by the U.S. Virgin Islands Dept. of Planning and Natural Resources. This orchid grows naturally on the southern dry and wind-swept slopes found on the east-end of St. Croix. It can be found growing among cacti and bromeliads. Due to disturbance to the native habitat from land development, private collectors, and natural disasters, the population has diminished. Tissue culture is being successfully used in a conservation effort for this endangered species. Maturing seed pods were collected and surface disinfested and established in vitro. The medium consisted of one half Murashige & Skoog salts, Nitsch & Nitsch vitamins, 20 g/L sucrose, 2 g/L soy peptone, 5 g/L activated charcoal and 8 g/L agar. Seeds were spread on the medium in 15 × 100-mm petri plates and grown at 25 °C under a 16-h photoperiod. Seed germination occurred within 2 months with the development of protocorms. Leaves and roots developed by 5 months, at which time they were separated and transferred to fresh medium. At 8 months, they were established in a greenhouse and released back into their environment within 12 months. In vitro germination of the Sandy Point Orchid seed is an effective way of conserving this endangered species.