bluuebunny/crossref_metadata_2025 huggingface dataset:
Planting Date Influences on Yield and Fruit Size of Jack-olantern Pumpkins
Authors: Maynard* Elizabeth T.
Published: February 2019

In northern Indiana, jack-o-lantern pumpkins (Cucurbita pepo) can be planted from late May through June to produce mature fruit for sales associated with Halloween. Field trials were conducted to evaluate the influence of planting date on pumpkin yield and yield components. `Gold Medal' and `Magic Lantern' pumpkins were each seeded on three planting dates (PD) in 2002 (31 May, 10 and 20 June 10) and 2003 (5, 16, and 25 June). Each planting date was harvested between 100 and 110 days after planting. The weight per plant of pumpkins that were completely mature (orange) was greatest for the June 10 planting in 2002 (14.9 kg vs. 12.5 kg for 1st and 12.2 kg for 3rd PD), but did not differ among dates in 2003 (PD1: 10.9 kg, PD2: 10.4 kg, PD3: 9.0 kg). The number of orange pumpkins per plant was lowest for the 20 June 2002 planting (1.63 vs. 1.88 for 1st and 1.91 for 2nd PD) but did not differ among dates in 2003 (PD1: 1.08, PD2: 1.20, PD3: 1.19). The average weight of an orange pumpkin was lowest for the 31 May 200 planting date (7.17 kg vs. 8.35 kg for 2nd and 7.89 kg for 3rd PD) and highest for the 5 June 2003 planting date (10.6 kg vs. 9.07 kg for 2nd and 8.16 kg for 3rd PD). In both years the last planting date produced the least weight per plant, and in 2002 the fewest number, of pumpkins that had begun to turn orange plus fully orange pumpkins. The two cultivars produced similar weight per plant and responded similarly to planting date, but `Gold Medal' produced fewer and larger fruit. No planting date consistently produced the greatest yield or largest fruit.
Effects of Ultrasonic Wave on Water Conditions, Antioxidases, and Free Radical in Cut Nymphaea tetragona During Cold Wet Storage
Authors: He Wenting , Guo Weiming , Jiang* Zhongchun
Published: February 2019

Effects of two pretreatments, i.e., ultrasonic wave (UW) and ultrasonic wave plus preservative solution (UW+PS), on water conditions of flower stem and membrane stability of petals in Nymphaea tetragona during 6-d cold wet storage. Compared with no pretreatment control, the two pretreatments prolonged the vase life and improved water conditions of the cut flower during cold storage to different degrees. Fresh weight of flower stems and relative water content of petals increased during cold storage. The water utilization efficiency of flower stem and water potential in different parts of flower stem were improved significantly as a result of the pretreatments. Although both pretreatments helped the cut flowers maintain favorable water relations, the effects of UW + PS combined pretreatment were better than UW pretreatment alone. In addition, UW and UW+PS inhibited the increase in the contents of lipid peroxidation product malondialdehyde (MDA) and superoxide anion in petals. UW + PS promoted superoxide dismutase (SOD) and catalase (CAT) activities in petals during cold storage to a greater degree than did UW.
Regulatory Properties of Apple Leaf Cytosolic Fructose-1,6-bisphosphatase
Authors: Zhou* Rui , Cheng Lailiang
Published: February 2019

Cytosolic fructose-1,6-bisphosphatase (cytoFBPase) (EC 3.1.3.11) occupies a strategic site in sucrose synthesis and has been demonstrated to play a key role in carbon partitioning between sucrose and starch in non-sorbitol forming plants. In addition to sucrose and starch, Sorbitol is the primary photosynthetic end product in the leaves of many tree fruit species in the Rosaceae family. To understand the biochemical regulation of photosynthetic carbon partitioning between sorbitol, sucrose and starch in sorbitol synthesizing species, we purified cytoFB-Pase to apparent homogeneity from apple leaves. The enzyme was a homotetramer with a subunit mass of 37 kDa. It was highly specific for fructose-1,6-bisphosphate with a Km of 3.1 μm and a Vmax of 48 units/mg protein. Either Mg2+ or Mn2+ was required for its activity with a Km of 0.59 mm and 62 μM, respectively. Li+, Ca2+, Zn2+, Cu2+ and Hg2+ inhibited whereas Mn2+ enhanced the Mg2+-activated enzyme activity. Fructose-6-phosphate was found to be a mixed type inhibitor with a Ki of 0.47 mm. Fructose 2,6-bisphosphate (F2,6BP) competitively inhibited the enzyme activity and changed the substrate saturation curve from hyperbolic to sigmoidal. Adenosine monophosphate (AMP) was a non-competitive inhibitor for the enzyme. F2,6BP interacted with AMP to inhibit the enzyme in a synergistic way. Dihydroxyacetone phosphate did not have inhibitory effect on apple leaf cytosolic FBPase activity. Sorbitol increased the susceptibility of the enzyme to the inhibition by F1,6BP. The presence of sorbitol in the reaction mixture led to a reduction in the enzyme activity.
Automatic Irrigation of Container Plants in Outdoor Sales Area
Authors: Lewis* Kyle P. , Buxton Jack W.
Published: February 2019

Maintaining adequate water for container plants in outdoor sales areas is difficult during the late spring and summer. In mass marketing areas employees are uninformed about the water requirements of plants under various environmental conditions. Plants often are severely stressed and over all quality reduced. A system was developed to automatically irrigate container plants in an outdoor sales area. The system is a modification of the Controlled Water Table (CWT) irrigation system developed at the Univ. of Kentucky (U.K.). The sales area consisted of 2 shelves each 2.44 m long and 0.28 m wide. A trough was constructed from a 5-cm diameter pipe with a 1/4 slot; it was attached to the back side of the shelf. One side of a capillary mat, placed on the shelves, was suspended in the trough containing water. Two systems were used to maintain the level of water in the trough. One was a small float valve installed in a 10-cm PVC pipe which was attached to the 5-cm PVC pipe. The float was adjusted to maintain the water in the trough 2 cm below the top of the shelf. The water reservoir consisted of a 20-cm diameter PVC pipe, 1.22 m long that held 70 L of water. A second system maintained a constant water level in the trough using Torricellian tube principle. The water reservoir was the same as above except it was tightly sealed so no air could leak from the system. The water table was maintained 2 cm below the bench surface by rotating a hole in small cap. A variety of plants in containers, ranging from 10 cm to 5 L pots were maintained without water stress, in a greenhouse environment as well in an outdoor environment for several weeks.
Physiological Effects of Drought Stress on Two Commercial Cultivars of the American Cranberry (Vaccinium macrocarpon)
Authors: Cesped-Ruiz* Ricardo , Huang Bingru
Published: February 2019

The American cranberry often undergoes drought stress during the summer. However, the physiological response of this species to drought is not well understood. This study was designed to determine the effects of drought on two commercial cranberry cultivars of high potential yield, `Ben Lear' and `Stevens', during a vegetative stage. The plants were subjected to drought for 15 days in a greenhouse. Soil water content, leaf water content, leaf photosynthetic rate, stomatal conductance, transpiration, differential leaf-air temperature, photochemical efficiency (Fv'/Fm') and the actual PSII efficiency (deltaF/Fm') decreased in those plants subjected to drought. Drought reduced differential leaf-air temperature at day 6 of treatment and stomatal conductance and transpiration starting at day 9 and photosynthetic rate at day 13. Drought decreased leaf water content at day 14 and Fv'/Fm' and PSII efficiency at day 15. Our results indicated that cranberry plants in vegetative stage were sensitive to drought for both cultivars and stomatal conductance was the most sensitive parameter among those examined for both cultivars.
Growth iInhibition of Pathogenic Bacteria by Artificially grown Ipomoea batatas (L.) Leaf
Authors: Islam* MD. Shahidul , Jalaluddin M. , Yoshimoto M. , Yamakawa O.
Published: February 2019

The antibacterial activity of artificially grown sweetpotato [Ipomoea batatas (L.) Lam.] leaves was investigated against both gram positive and gram negative bacteria namely Escherichia coli (O157:H7), Bacillus and Ecolai using three different cultivars, which are developed to use as a leafy vegetables namely Simon-1, Kyushu-119 and Elegant Summer. The sweetpotato leaves were grown under different temperatures (20 °C, 25 °C, and 30 °C) and artificial shading (O%, 40% and 80%) conditions. There were some cultivar differences but the lyophilized leaf powder (100 mg) from all the cultivars in the Trypto Soya Broth cultivation medium (10 mL) strongly suppressed the growth of all the bacteria studied and its effect was detectable even after autoclave treatment. But the antibacterial extract of the leaves had no effect on the growth of five types of bifidobacterium useful for human health. The water extracted antibacterial fractions from all the cultivars were viscous and the color was brown. Furthermore, the leaves grown under moderate low temperature (20 °C) with 0% shading treatments strongly suppressed the bacterial growth as comported to other treatments, which was accompanied by significantly high accumulation of sugar and polyphenol contents in the leaves. The results also suggest that there were a strong relationship among bacterial growth and antioxidatative compounds in the sweetpotato leaves. Therefore, the antibacterial action of sweetpotato leaves may depend on their antioxidative compounds or/and pectin like materials. Thus, the practical use of sweetpotato leaves is expected to prevent bacteria caused food poisoning.
Water Loss Estimates of Three Containerized Landscape Tree Species Using Thermal Dissipation Probes and Load Cells
Authors: Montague* Thayne
Published: February 2019

Granier style thermal dissipation probes (TDP) have been used to estimate whole plant water loss on a variety of tree and vine species. However, studies using TDPs to investigate water loss of landscape tree species is rare. This research compared containerized tree water loss estimates of three landscape tree species using TDPs with containerized tree water loss estimates as measured by load cells. Over a three-year period, established, 5.0 cm caliper Bradford pear (Pyrus calleryana `Bradford'), English oak (Quercus robar), and sweetgum (Liquidambar styraciflua `Rotundiloba') trees in 75 L containers were placed on load cells, and water loss was measured for a 60-d period. One 3.0 cm TDP was placed into the north side of each trunk 30 cm above soil level. To reduce evaporation, container growing media was covered with plastic. Each night, plants were irrigated to soil field capacity and allowed to drain. To provide thermal insulation TDPs and tree trunks (up to 30 cm) were covered with aluminum foil coated bubble wrap. Hourly TDP water loss estimates for each species over a three-day period indicate TDP estimated water loss followed a similar trend as load cell estimated water loss. However, TDP estimates were generally less, especially during peak transpiration periods. In addition, mean, total daily water loss estimates for each species was less for TDP estimated water loss when compared to load cell estimated water loss. Although TDP estimated water loss has been verified for several plant species, these data suggest potential errors can arise when using TDPs to estimate water loss of select landscape tree species. Additional work is likely needed to confirm estimated sap flow using TDPs for many tree species.
`Shenandoah': A New Fire Blight-resistant Pear Cultivar
Authors: Bell* Richard L. , van der Zwet Tom , Miller Diane D.
Published: February 2019

`Shenandoah' is a new European pear (Pyrus communis L.) cultivar which combines resistance to fire blight with fruit of excellent quality. The original seedling tree was selected in 1985 from a cross of `Max Red Bartlett'× US 56112-146, and was tested under the original seedling number, US 78304-057. The fruit of `Shenandoah' is pyriform in shape, and moderately large in size, averaging 72 mm in diameter and 92 mm in height. Skin color at harvest is light green, turning yellow-green when ripe. The skin finish is glossy, and 10% to 20% of the fruit surface is blushed red. There is light tan russet at the calyx. Lenticles are slightly conspicuous, and are surrounded by small, light brown russet. The stem is medium to long (≈25 mm), of medium thickness, and slightly curved. Harvest maturity occurs about four weeks after `Bartlett', and the fruit will store in refrigerated (-1 °C) air storage for at least four months without core breakdown or superficial scald. The flesh texture is moderately fine, juicy, and buttery. Grit cells are moderately small and occur primarily around the core and in a thin layer under the skin. The flavor is aromatic, similar to `Bartlett', and is moderately acidic during the first two months of storage, becoming subacid after longer storage. The tree is moderate in vigor on `Bartlett' seedling and `OHxF 97' rootstocks, and upright-spreading in habit. Shenandoah' blooms in mid-season, similar to `Bartlett'. Yield has been moderately high and precocious, and with no pronounced biennial pattern. Fire blight resistance is similar to `Seckel', with infections extending no further than 1-year-old branches. Artificial blossom inoculations indicate a moderate degree of blossom resistance to fire blight infection.
Correlation of Increased Alternative Oxidase Gene Expression With Reduced Chilling Injury in Cold-stored Tomatoes (Lycopersicon esculentum)
Authors: Fung* Raymond , Wang Chien , Smith David , Gross Kenneth , Tao Yang , Tian Meisheng
Published: February 2019

Methyl salicylate (MeSA) and Methyl jasmonate (MeJA) treatments increased chilling resistance of light red tomato (Lycopersicon esculentum cv. Beefsteak) and extended shelf life and fresh-cut quality. We previously showed induction of AOX expression by low temperature and that induction of AOX transcript by MeSA and MeJA is correlated with resistance against chilling injury in peppers. Here, we investigate tomato, which is genetically closely related to peppers and belongs to the same Solanaceae family. In particular, we used four EST tomato clones of AOX from the public database that belong to two distinctly related families, 1 and 2 defined in plants. Three clones designated as LeAOX1a, 1b and 1c and the fourth clone as LeAOX2. Probes for these four genes were designed and Southern blotting done to confirm that they do not cross-hybridize. We will present data from Southern, Northern hybridization and RT-PCR to show: (1) gene copy number of each of these AOX members in the tomato genome; (2) gene-specific expression profiles in response to MeSA and MeJA in cold stored tomato; and (3) the relative transcript abundance of these four AOX genes.
Hydrogel Amendments Do Not Decrease the Time Interval Between Waterings for Container-grown Geranium and Ninebark
Authors: Gillman* Jeffrey H.
Published: February 2019

Hydrogels are crystals that can suck up 600 or more times their weight in water. These gels are sold as additives for soils and container media for the purpose of reducing the frequency of watering. Five different hydrogels and a control were tested on geranium and 3 different hydrogels and a control were tested on ninebark to see how long plants could be kept healthy without watering. Growth was roughly similar among the control and the different hydrogels tested with the exception of Hydrosorb™, which stunted the growth of the ninebark. After plants reached a size that was considered saleable watering was stopped and the plants were allowed to dry out. None of the hydrogels kept the plants supplied with water for any longer than the controls. Hydrosorb™ did appear to keep ninebarks at a healthy water potential for longer than the other hydrogels and the control, however, this is almost certainly because of the smaller size of the plants.
Activation of Isopentenyl Transfarese (ipt) Gene in Transformed Watermelon Influences Seed Number and Other Characteristics
Authors: Goktepe Fahrettin , Hughes* Harrison
Published: February 2019

The watermelon cv. Crimson Sweet was transformed with the copper inducible isopentenyl transferase, the rate-limiting step in cytokinin biosynthesis, gene via Agrobacterium tumafaciences (LBA4404). Transformed (ipt) and nontransformed plants were regenerated from tissue culture and clonally propagated by the rooting of leaf node cuttings. Twelve plants of each were grown in 1-gal. pots. Once the plants initiated new growth both transgenic plants and wild type plants were sprayed with one of four different concentrations (0, 5, 10, & 50 μm) of CuSO4. The experimental unit was a single plant with three replicates. The growth rate, number of leaves, flowers, lateral shoots, and chlorophyll content were measured weekly for five weeks. Treated transgenic plants had greater numbers of leaves, flowers and lateral branches as well as higher chlorophyll levels. Pollen viability was examined in all treatments with no differences among treatments. Plants of both types were self pollinated to generate seeds. Female flowers were bagged before opening and then selfed. Selfed flowers were bagged for at least two days. The fruits were grown for eight to ten weeks with support. Once they reached maturity, fruits were harvested and fruit shape, flesh color, brix, number of normal seeds, number of colored but empty seeds and number of white seeds were recorded. Significant differences were observed only in seed number between wild type and transgenic (both treated and nontreated,) watermelon fruits. The number of seeds in transgenic watermelon plants treated with CuSO4 was reduced to about 5% to 7% of wild type plants. Transgenic plants which received no CuSO4 had approximately 33% to 50% of the seed of wild type.
Effect of CdCl2 on the Growth and Antioxidases Activities in Transgenic Metallothionein and Wild Type Tobacco Leaves
Authors: Sheng* Jiping , Shen Lin , Ru Binggen
Published: February 2019

Metallothioneins (MTs) has selective capability to bind heavy metals such as Cd and Pb. Former study in our lab showed that MT gene from mouse was transferred into tobacco to absorb more heavy metals from soil. This study was conducted to plant transgenic tobacco and wild type tobacco on MS media with 20 μmol·L-1 CdCl2. Transgenic tobacco grew strong, whereas the growth of wild type tobacco was severely prohibited. At 21st day, an average single transgenic plant weight was 1.5 times higher than that of wild type, and its height was also 1.33 higher. The activities of antioxidases, such as POD, CAT, PPO in transgenic tobacco leaves showed significant lower than that of wild type, which was 32.3%, 43.3%, 187.5% lower respectively. The results indicated that the transgenic MT tobacco had higher Cd tolerance, and a promising future in the application of environmental cleaning.
Shipping and 1-Methylcyclopropene (1-MCP) Effects on Shelf Life of Diascia ×hybrida
Authors: Beach* Shannon E. , Starman Terri W.
Published: February 2019

Diascia ×hybrida (diascia) is a cool season vegetative annual produced in 6 weeks in an 11.4-cm pot under greenhouse production. Early experiments noted that during simulated shipping in a growth chamber at 26.7 ± 0.3 °C, 0 μmol·m-2·s-1 PPF and 50% RH, diascia flowers abscised. To test the effect of 1-MCP on retention of flowers during shipping, three hundred diascia plants were grown under temperature set points of 24°/18 °C day/night in a glass greenhouse. Three harvests of 42 plants each were made as plants became marketable i.e., open flowers on six racemes. The treatments were factorial with three shipping durations (0, 1, or 2 days) and two 1-MCP (1-Methylcyclopropene, Ethylboc, Floralife, Waterboro, S.C.) treatments (0 mg·L-1 and the commercially recommended application rate) and seven plants per treatment. Plants were boxed and sealed under 4-mL clear plastic tarps with duct tape and then treated with 1-MCP gas or water for 4 hours before moving to the growth room (19 °C, 10 μmol·m-2·s-1 PPF) for 2 weeks. They remained in the boxes for the duration of simulated shipping treatments. Flower number, racemes with open flowers and a quality rating were given when removed from the shipping boxes. For plants in the first and second harvests, 1-MCP significantly reduced flower and raceme abscission 1 week after shipping regardless of shipping duration; this was not seen in the third harvest. Two weeks post shipment there was no difference in flower numbers between 1-MCP treated and untreated plants. With two exceptions, no differences among measured variables occurred due to shipping duration.
The Effects of Cultivar on the Arbuscular Mycorrhizal Fungi Symbiosis in Strawberries
Authors: Ross* Marjorie E. , Hoover Emily E.
Published: February 2019

Cultivar may cause variation in arbuscular mycorrhizal fungi (AMF) colonization levels leading to differences in shoot growth and runner formation, and in pathogen control in strawberries. However, a clear consensus has not been reached regarding the degree to which cultivar affects the formation of the symbiosis or its functioning. The study was conducted on four commercial strawberry farms in Minnesota and Wisconsin to compare, within a farm, mycorrhizal colonization and plant response among three strawberry cultivars: `Winona', `Anapolis' and `Jewel'. At each farm, two 6 × 6 meter plots of each cultivar were randomly selected. On each of three sampling dates, 4 whole plants and soil samples were collected from these plots in the 2003 field season. Roots were separated from shoots and leaves, and fresh and dry weights were taken. Leaves and soil were dried, weighed, and submitted for nutrient analysis. Soil nutrient analyses include phosphorus (Bray P), potassium, pH, buffer pH and organic matter. Leaf tissue analyses include P, K, Ca, Mg, Na, AL Fe, MN Zn, Cu, B, Pb, Ni, Cr, and Cd. Roots were collected, frozen, and prepared for scoring using methods adapted from Koske and Gemma (1989). Presence of mycorrhizal colonization is being scored using the methods of McGongle et al. (1990). Levels of mycorrhizal colonization among different strawberry cultivars will be compared. We will also use biomass measurements, to determine mycorrhizal effects on plant growth among different cultivars. Soil and leaf analysis data will be used to determine effects of AMF on plant nutrition and compare effects among cultivars.
CO2 Assimilation, Photosynthetic Enzymes, and Carbohydrates of Grape Leaves (Vitis labrusca L. cv. Concord) in Response to Iron Supply
Authors: Smith* Brandon R. , Chen Li-Song , Cheng Lailiang
Published: February 2019

Own-rooted one-year-old `Concord' grapevines were fertigated twice weekly for 11 weeks with 1, 10, 20, 50, OR 100 μmol iron (Fe) from ferric ethylenediamine di (o-hydroxyphenylacetic) acid in a complete nutrient solution. As Fe supply increased, leaf total Fe content did not change, whereas active Fe (extracted by 2, 2'-dipyridyl) and total chlorophyll content increased curvilinearly. CO2 assimilation and stomatal conductance increased curvilinearly with increasing active Fe, whereas intercellular CO2 concentrations decreased linearly. Activities of key Calvin cycle enzymes, Rubisco, NADP-glyceraldehyde-3-phosphate dehydrogenase, phosphoribulokinase, stromal fructose-1,6-bisphosphatase (FBPase), and a key enzyme in sucrose synthesis, cytosolic FBPase, all increased linearly with increasing active Fe. No difference was found in the activities of ADP-glucose pyrophosphorylase and sucrose phosphate synthase of leaves between the lowest and the highest treatments, whereas slightly lower activities were observed in the middle Fe treatments. Content of 3-phosphoglycerate increased curvilinearly with increased active Fe, whereas glucose-6-phosphate and fructose-6-phosphate did not change. Glucose, fructose, sucrose, starch, and total non-structural carbohydrates at both dusk and pre-dawn increased with increasing active Fe. Carbon export from starch breakdown during the night, calculated as the difference between dusk and predawn levels, increased as active Fe increased. In conclusion, Fe limitation reduces the activities of Rubisco and other photosynthetic enzymes, and hence CO2 assimilation capacity. Fe-deficient grapevines have lower concentrations of non-structural carbohydrates in source leaves, and therefore, are source limited.
Effects of Harvest Pruning on `Thompson Seedless' Grapevines
Authors: Fidelibus* Matthew , Smart David
Published: February 2019

In response to diminishing returns, the California raisin industry is rapidly adopting mechanical raisin harvesting practices to reduce cost. Whether the fruit will dry on the vine, or be laid on continuous trays to dry, the first step of mechanical raisin harvest generally involves severing the canes of vines with ripe fruit, a practice known as harvest pruning (HP). The potential physiological implications of HP are uncertain, so an experiment was established to assess the effects of HP on 40-year-old `Thompson Seedless' grapevines (Vitis vinifera L.) that were on their own roots, head-trained and cane pruned, and supported by a single wire trellis. Fruit achieved 20 °Brix by 2 Sept., at which time vines had a leaf area of about 21.6 m2. About 60% of the canopy leaf area was from canes, and thus removed by HP. The net CO2 assimilation rate (A) of mature leaves on renewal shoots began to decline after about 8 Aug., but they maintained a positive A until at least 31 Oct. Reduced A was due, in part, to chlorophyll degradation as evidenced by a decline in SPAD units occurring over the period that A declined. Harvest pruning generally did not affect A of mature leaves retained on renewal shoots, but those leaves maintained a positive A for at least 60 d after HP indicating that HP reduced the vines' photosynthetic capacity. Soil respiration also declined between summer and winter, probably in response to decreasing soil temperatures. Soil respiration was similar among HP and non-HP vines, except about 30 d after HP, when HP vines had about 30% lower soil respiration values than non-HP vines. Root growth was observed in summer and fall regardless of whether vines were subjected to HP.
Evaluation of Grapevine `Cabernet Sauvignon' Response to Two Deficit Irrigation Strategies
Authors: Basinger Ashley , Hellman* Edward , Shelby Steven
Published: February 2019

Partial rootzone drying (PRD) and regulated deficit irrigation (RDI) were evaluated separately over two years on Vitis vinifera L. variety `Cabernet Sauvignon' for their applicability to commercial vineyards in Texas and to investigate their potential for enhancing grapevine acclimation and cold hardiness. PRD treatments compared the alternating-half-rootzone water application strategy of PRD to an equal volume of water applied to the entire rootzone and a 2× volume of water applied to the entire rootzone. RDI treatments compared the effects of deficit irrigation at different developmental stages of grapevine: post-fruit set to veraison; veraison to harvest; post-harvest; and a no-deficit control. The PRD treatment plots performed similarly to the equal volume treatment plots for yield and fruit composition. The double-volume treatment had a trend to higher yield in 2002 and statistically significant higher yields in 2003, and slightly lower soluble solids content of fruit in 2002. Thus, the two deficit treatments, PRD and Equal, experienced only a small reduction in performance while enabling reduced water usage. The PRD alternating-half-rootzone strategy demonstrated no advantage over a standard deficit irrigation strategy. Grapevines irrigated with the RDI strategy responded to this treatment most during the post-fruit set to veraison stage of development, which had lower yields and higher fruit soluble solids compared to the no-deficit treatment in 2002. Both PRD and RDI deficit irrigation strategies significantly increased the earliness and rate of periderm development on shoots in both years, but did not result in consistently greater cold hardiness compared to no-deficit treatments.
Control of the Foliar Disease, Septoria lycopersici, in Organic Tomato Production
Authors: Joslin* Karen , Taber Henry , Helland Sara , Gleason Mark
Published: February 2019

Disease management in organic tomato production poses one of the greatest challenges for organic producers in humid climates. Both organic and conventional tomato growers have relied on copper (Cu) fungicides to control many diseases, including Septoria lycopersici common in tomato production. Concerns have been raised regarding the use of Cu fungicides, because of their potential to cause plant damage and toxicity to beneficial organisms. The objectives of this research were to: 1) investigate the efficacy of compost tea made from either windrow composted cattle manure (WCCM) or vermicomposted cattle manure (VCM), and 2) compare the efficacy of organic fungicides with conventional fungicides to control S. lycopersici in organic tomatoes. Treatments included 1) a control, 2) a conventional treatment in which fungicide applications of Bravo plus Cu and Quadris plus Cu were alternated, 3) copper fungicide (Champion), 4) Serenade™ Fungicide (Bacillus subtilis), 5) WCCM compost tea, and 6) VCM compost tea. Disease pressure was mostly from the bacteria speck/spot complex. Disease severity was significantly (P < 0.05) reduced and marketable yield was 60% higher with the two Cu treatments (No. 2 and 3), compared to other treatments. A follow-up greenhouse experiment is in progress and will be presented with the field data.
Clinic Outreach Impact Survey
Authors: Badertscher* Kerrie B. , O'Meara Carol A.
Published: February 2019

Since the 1970's, the Colorado Master Gardenersm (MG) program in Boulder County has had volunteer opportunities external to the extension office site. Collaboration occurs with various green industry locations via “clinics”. Volunteers are on location Friday through Sunday, April through mid-July to answer questions for the public at large. Due to the length of time this program had been in place, the staff time and resources committed to it, and budget cutbacks, need for a study of impact and effectiveness of this program was identified. A three-year study was conducted to determine efficacy, pertinence and should this system remain status quo. In year 1, a sampling of the general public was conducted to determine: behavioral change as a result of receiving information (such as a diagnosis); was the information delivered in a timely fashion; satisfaction level; pesticide usage trends; continuance of this program and other data points. In year 2, active MG's in Boulder County were surveyed about participation at various facilities, information about clientele activity, and success rate with clients. Additionally, their comfort level on ability to assist clients plus their perception of the value of clinics to the community were surveyed. Data on diagnostics was correlated with weekly statistics. In year 3, partnering Green Industry collaborators were surveyed to gauge satisfaction with clinic service, timeliness of clinic schedule, and value of clinic service to business, and overall benefits to their staff resources. Reports on each survey will be delivered.
Evaluation of Pendemethlin for Selected Containerized Perennials
Authors: Mathers Hannah M. , Pope* Jennifer A.
Published: February 2019

Specialty crops generate $40 billion in annual sales comprising a significant portion (40%) of total agricultural sales. The diversity of plant material is a limiting factor for new herbicide registration. The IR-4 program facilitates the labeling of new or experimental pesticides for minor use crops. The objective of this experiment was to determine the ornamental phytotoxicity and efficacy of Pendemethalin for selected 1-gallon perennials. Phytotoxicity was evaluated on Armeria maritime, Boltonia, Buddleaia davidii, Cercis Canadensis, Delphinium, Fragaria, Oenothera, Panicum virgatum, Papaver orientale, Phlox subulata, Rudebeckia fulgida, Scabiosa columbara, Schizachyrium scoparium and Sedum spectabile. Herbicide was applied at 1X, 2X, and 4X rates according to IR-4 protocols with a weedy check included. Pendemethalin was applied twice throughout the study, the second spray occurring two months after the first. Visual ratings were taken of efficacy (scale, 0-10) and phytotoxicity (scale, 1-10, 10 = complete kill) at 15 and 45 days after treatment (DAT). Buddleaia displayed symptoms of phytotoxicity at the 4x rate but grew out of the initial effects of the herbicide. By trials end, Oenothera at 1×, 2×, 4× rates, Fragaria and Phlox at 2× and 4× and Canadensis at 4× had significantly reduced plant quality. All remaining species had acceptable plant quality. Efficacy was evaluated following the same protocol as above with a weedy seed check using a 1/8th tsp.mixture of Digitaria sanguinalis, Poa annua, and Senecio vulgaris per 1-gallon pot. Overall no treatment provided an acceptable level of weed control. The herbicide provided little control of Groundsel, was moderately effective in controlling the Bluegrass, and provided 100% control of the Crabgrass.
Foliar Applied Strontium as a Tracer for Calcium Transport in Apple Trees
Authors: Rosen* Carl , Bierman Peter , Telias Adriana , Shen Yizhen , Hooverf Emily
Published: February 2019

A field experiment was conducted at the Horticultural Research Center in Chanhassen, Minn. to help refine recommendations for use of calcium (Ca) sprays to reduce the incidence of bitter pit in `Honeycrisp' apple. Specific objectives were to: evaluate the amount of translocation from leaves to fruit using strontium (Sr) as a tracer for potential Ca movement, determine whether there are differences in translocation in early vs. later phases of fruit development, and evaluate the effect of an experimental adjuvant on spray efficacy. Seven treatments tested included the following: 1) Control (no Sr applied), 2) Sr without adjuvant, fruit covered during spray application, full season, 3) Sr without adjuvant, fruit uncovered during spray application, full season, 4) Sr + adjuvant, fruit covered during spray application, full season, 5) Sr + adjuvant, fruit uncovered during spray application, 6) Sr + adjuvant, fruit covered during spray application, late season, 7) Sr + adjuvant, fruit uncovered during spray application, late season. Results from this study strongly suggest that Sr is a suitable tracer for foliar applied Ca. Up to 18% of the Sr applied to leaves was translocated to fruit. Eight full season spray applications more than doubled the concentration and content of fruit Sr compared to four late season sprays. The experimental adjuvant was found to double Sr absorption by and translocation to fruit compared to not using an adjuvant. Implications for foliar application of Ca to apple trees will be discussed.
The Influence of Preharvest Calcium Applications on Postharvest Quality and Yield of `Sweet Charlie' Strawberry
Authors: Esmel* Camille , Duval John R. , Simonne E.H. , Sargent Steven A.
Published: February 2019

Strawberries are a high value commodity with a short shelf life. Florida is the largest producer of winter strawberries in the United States with 2,790 hectares of production, 90% are located in Hillsborough County. Many Florida growers apply additional calcium (Ca) as a foliar spray despite the lack of conclusive evidence of an increase in fruit quality or yield. It is believed that additional Ca will improve cell wall integrity through Ca linkages with pectins with in the cell wall and increase fruit firmness. Preharvest applications of calcium chloride have shown to delay the ripening of strawberry fruit and mold development. The objectives of this two year study were to determine the effects of Ca on yield, growth, and postharvest quality of strawberry when applied to the soil or as a foliar spray. `Sweet Charlie' strawberry plants were grown on a Seffner fine sand in Dover, Fla. The experimental design was a split-block replicated four times with soil and foliar Ca applications. Main plots consisted of a broadcast preplant incorporation of gypsum (calcium sulfate) 0 kg·ha-1, 36.7 kg·ha-1, and 73.4 kg·ha-1. Sub-plots consisted of foliar applications of 400 mg·L-1 Ca from calcium sulfate, 400 and 800 mg·L-1 Ca from calcium chloride and a water control applied weekly throughout the 2002-03 and 2003-04 growing season. Yield data was collected twice weekly through out the growing season. Fruits were graded for quality based upon size, visual appearance of pathogens degradation, frost/water damage, and misshapen form. Calcium content was determined for leaves, fruit, and calyxes in January and March. Postharvest quality evaluations of pH, titratable acidy, soluble solids, and firmness (Instron 4411) were determined in January and March.
Response of Individual Plant Actual Evapotranspiration to Canopy Closure: A Three Dimensional Model Derived from Viburnum odoratissimum
Authors: Beeson* Richard C.
Published: February 2019

ng production and in landscapes, woody plants are initially spaced apart to develop to desirable landscape quality. As plants grow and canopies begin to interact, canopies transform from individual isolated canopies to one large, closed canopy system. Changes in individual plant actual evapotranspiration (ETA) during the transitions between isolated and closed canopies are 30% on average. Such changes can have a substantial impact on supplemental irrigation requirements, both decreasing with closure and increasing with random removal of plants from a closed canopy. Data will be presented demonstrating changes in ETA as canopy closure progresses from isolated plants through 33%, 67%, and 100% canopy closure. Concurrent data from plants of marketable size grown in 3.8, 10.4, and 26.6 L containers were used to evaluate effects of canopy vertical thickness, and total canopy height, on the changes in ETA relative to degree of canopy closure. Contributions to ETA at 100% canopy closure and isolated plants from leaves at various depths within a canopy will be discussed.
Application of Kaolin-based Particle Film on Pecan Trees: Consequences on Leaf Gas Exchange, Stem Water Potential, Nut Quality, and Insect Populations
Authors: Lombardini* Leonardo , Glenn D. Michael , Harris Marvin K.
Published: February 2019

Trials were established in Summer 2002 and 2003 to test the consequences of the application of a kaolin-based particle film (Surround WP, Engelhard Corp.) on gas exchange, nut quality, casebearer density and population of natural predators (insects and arachnids) on pecan (Carya illinoinensis, cv. `Pawnee') trees. Film application started immediately after bud break and was repeated every 7-10 days for seven (2002) or nine (2003) times during the season. On both years, treated trees frequently showed lower leaf temperature (up to 4 °C) than untreated trees. Leaf net assimilation rate, stomatal conductance and stem water potential were not affected by film application. Nut size and quality did not differ between the two treatments. In 2003, shellout (percentage of nut consisting of kernel) was in fact 54.2% and 55.5% for treated and control trees, respectively. Moreover, the two treatments yielded similar percentage of kernel crop grading as fancy, choice, standard and damaged. Similar were also the percentages of kernels that showed damage caused by stink bugs. Only on one date the number of adult yellow pecan aphids (Monelliopsis pecanis) counted on film-treated leaves was lower than in control leaves. In general, the density of common natural predators (lady beetles, green lacewings, spiders) of pecan pests did not differ between the two treatments; however, the number of green lacewing eggs was frequently lower on film-treated leaves. In film-treated trees the number of nutlets damaged by pecan nut casebearer (Acrobasis nuxvorella) was significantly higher than that observed on trees treated with conventional insecticide (24.2% infested nutlets vs. 9.3%, respectively) and did not differ from trees that did not receive either product (29.9%).
Pollination Study of Clementine Mandarins, `Afourer' Mandarin, `Tahoe Gold' Mandarin and Effect on Fruit Set and Seediness in California
Authors: Chao* C. Thomas
Published: February 2019

Compatibilities among mandarin cultivars raise concern, especially related to the seediness issue in mandarin production. A hand cross-pollination study was conducted in 2002 and 2003 at the UC Lind-cove Research and Extension Center, Exeter, California. There were 0.86% (1/116) (4 seeds) and 0% (0/137) fruit set from `Fina Sodea' Clementine × `Tahoe Gold' mandarin in 2002 and 2003, respectively. There were 13.59% (14/103) (average 1.5 seeds/fruit) and 16.50% (17/103) (average 9.82 seeds/fruit) fruit set from `Nules' Clementine × `Tahoe Gold' mandarin (a triploid) in 2002 and 2003, respectively. There were 30.84% (33/107) (average 23.42 seeds/fruit) and 0% (0/110) fruit set from `Fina Sodea' Clementine × `Afourer' mandarin in 2002 and 2003, respectively. There were 39.62% (42/106) (average 25.36 seeds/fruit) and 4.92% (3/61) (average 31.66 seeds/fruit) fruit set from `Nules' Clementine × `Afourer' mandarin in 2002 and 2003, respectively. There was 28.32% (32/113) (average 12 seeds/fruit) from `Afourer' mandarin × `Fina Sodea' Clementine in 2002. There was 28.04% (30/107) (average 9.47 seeds/fruit) from `Afourer' mandarin × `Nules' Clementine in 2002. These results showed pollen of `Afourer' mandarin can cause large number of seed in both Clementine cultivars. The pollen from the triploid `Tahoe Gold' mandarin can set fruit and cause seeds in diploid `Nules' Clementine but not in diploid `Fina Sodea' Clementine. These results imply that proper buffer distance is needed between Clementines and `Afourer' mandarin in order to produce seedless mandarins in California.
Isolation and Characterization of a Putative Ascorbate Peroxidase from Citrus Center
Authors: Kunta MadhuraBabu , Louzada* Eliezer
Published: February 2019

Ascorbate Peroxidase (APX) is a heme-containing, non-glycosylated enzyme that destroys harmful hydrogen peroxide via the ascorbate glutathione pathway in plants. This enzyme is considered to be an indispensable part of the electron-scavenging pathway and is involved in preventing oxidative damage in plants. Using differential display RT-PCR and 5' RACE a full length c-DNA clone was isolated, from citrus, with very high similarity at the nucleotide and amino acid level, to ascorbate peroxidases from several plant species. It is well known that APXs have highly conserved motifs like the Arg-38, Ars-71, Glu-65 and Asp-208 residues around the distal Hist-42 and proximal His-163. These residues are essential for binding the ligand heme. Additionally, Trp-179 is conserved in most APXs and is the third participant in hydrogen bonding network, together with His-163 and Asp-208. All these conserved motifs were present in the putative APX from citrus in addition of the presence of the peroxidase active site motif residues (APITLRLAWHSA) and the peroxidase heme-ligand motif (DIVVLSGGHTL). Expression analysis in E. Coli reviewed a recombinant protein of 27 Kda.
Enhanced Histological Technique for Observation of Spathe Pigmentation in Anthurium species and Hybrids
Authors: Ehrenberger* Jennifer A. , Kuehnle Adelheid R.
Published: February 2019

A hybridization strategy for certain coloration could be developed based on accurate histological information of parental material together with the knowledge of heritability of color and color intensity. A sample of 12 Anthurium species and hybrids were histologically examined for pigmentation in spathes using a new method employing vacuum infiltration of spathe tissue with polyethylene glycol (PEG) prior to cross-sectioning. PEG infiltration displaces intercellular air spaces between cells. This method greatly improved the clarity of the cross sections and consequently improved observations of spatial localization of anthocyanins and chloroplasts. This infiltration method accurately identified the spatial localization of pigments for future breeding reference, notably among Anthurium species.
Molecular Marker Variability for Southern Root-Knot Nematode Resistance in Sweetpotato
Authors: Mcharo* Mwamburi , Labonte Don , Clark Chris , Hoy Mary
Published: February 2019

Using two sweetpotato (Ipomoea batatas (L.) Lam) F1 populations from diverse environments we investigated the AFLP marker profiles of the genotypes for association studies between the molecular markers and southern root-knot nematode (Meloidogyne incognita) resistance expression. Population one consisted of 51 half-sib genotypes developed at the Louisiana State Univ. AgCenter. The second population consisted of 51 full-sibs developed by the East African and International Potato Center sweetpotato breeding programs. Results for nematode resistance expression indicate a binomial distribution among the genotypes. Using analysis of molecular variance, logistic regression and discriminant analysis, AFLP markers that are most influential with respect to the phenotypic trait expression were selected for both populations. A comparative analysis of the power of models from the two statistical models for southern root-knot nematode resistance class prediction was also done. The diversity and possible universal similarity of influential markers between the two populations and the expected impact in sweetpotato breeding programs will be discussed.
Breeding Snap Beans for Cucumber Mosaic Virus (CMV) Resistance
Authors: Griffiths* Phillip
Published: February 2019

Cucumber mosaic virus (CMV) is an aphid-transmitted virus that infects snap bean growing regions in New York State and Wisconsin. The core collection of common bean accessions (Phaseolus vulgaris), the complete collection of scarlet runner bean accessions (Phaseolus coccineus) and snap/dry bean cultivars were screened for resistance to CMV. Although variation in foliar symptom expression was observed, no resistance was observed in 93 snap bean and16 dry bean cultivars tested, and only one of the 406 accessions from the core collection (PI 309881) was symptomless. PI 309881 did not have common bean characteristics, and was later identified as a tepary bean (Phaseolus acutifolius) accession based on morphology and PCR-RFLP of chloroplast DNA. Screening of 260 P. coccineus accessions was inaccurate when a visual rating of foliar symptoms was used. It was necessary to determine infection using ELISA and test plant screening with grey zuccini. Using this approach it was determined that 80 P. coccineus accessions were susceptible to CMV; however, the remaining accessions provided possible sources for transfer of CMV resistance to snap bean. Crosses of P. coccineus accessions were made to breeding line 5-593 and backcrossed to 5-593 and snap bean cultivar `Hystyle'. PI 309881 was crossed with ICA Pijao in order to develop interspecific hybrids. Populations were developed from the interspecific crosses/backcrosses and evaluated for CMV resistance using ELISA and visual ratings of foliar symptoms.