bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Chitinases from Dogwood Anthracnose Resistant and Susceptible Cornus Species
Authors: Cardwell Nicole A. , McDaniel Gary L.
Published: February 2019

The pathogenesis-related protein, chitinase, is implicated in the resistance mechanisms involved in dogwood anthracnose, which is caused by Discula destructiva. Chitinase isozymes were isolated from Discula-inoculated Cornus mas, a highly resistant species, and from inoculated C. florida, a highly susceptible species. Chitinase activity was identified in C. mas on days 2-12 following inoculation, but was expressed only on day 8 following inoculation in C. florida. Both dogwood species expressed a constitutive chitinase level in noninoculated control leaves, but Discula-inoculated leaves of C. mas contained three chitinase isozymes, whereas C. florida leaves expressed only two. Molecular masses of isozymes were 21, 32, and 35 kDa for C. mas and 21 and 35 kDa for C. florida. Isoelectric focusing demonstrated three chitinase isozyme isoelectric points for C. mas (pI = 5.6, 6.8, and 8.9), but only two for C. florida (pI = 5.6 and 6.8). These differences in synthesized isozymes and rate of accumulation suggest that chitinase may have a role in the defense of dogwood against D. destructiva infection.
Evaluation of Nitrogen Sources and Rates on the Yield and Quality of Sweet Onion
Authors: Arboleya Jorge , Delgado Diego , Pieri Santiago
Published: February 2019

During the 1980s, research was conducted mainly for long-day onion, with limited research on cultural practices for short-day cultivars, in Uruguay. Sweet onion production became important in Uruguay in 1992. Research was conducted on cultivar adaptation, sowing time, plant population, transplanting and direct-seeded methods, irrigation, and plant protection. Onion fertilization criteria were established for long-day cultivars in the southern region in the 1980s. National Research Inst. of Agriculture started a study on sweet onion fertilization using four N rates, 0, 60 120, and 180 kg/ha, and four N sources, urea, ammonium nitrate, potassium nitrate, and calcium nitrate. Nitrogen was applied into the soil 40% before transplanting and the remaining 60% in two applications in the spring. Granex 33 cultivar was transplanted on 27 June 1997 into a soil with the following characteristics, pH 6.4, P (Bray 1) 44.5 ppm, organic matter 3.3, and K 0.64 meq/100 g. Beds were separated 1.5 t, with four rows and plants 12 cm apart. Plant height and leaf color were evaluated. Lack of nitrogen and 60 kg N/ha showed lighter green colored leaves. Leaf, total plant, and soil samples were collected to determine nutrient status and dry matter production. Bulbing ratio was measured in 10 plants in each plot. Sweet onion quality was done by pyruvic acid analysis.
Field Evaluations of Nutrient Absorption Enhancer and Starter Fertilizer in Bell Pepper
Authors: Swiader John M. , Shoemaker William H.
Published: February 2019

In recent years, vegetable growers in the Midwestern United States have received much advertising information about using the synthetic protein polyaspartic acid (PA) in their fertility management program as a nutrient absorption enhancer. Supposedly, each long-chain PA molecule acts as an extension of the plant's root hairs; and by virtue of its negative charge, attracts nutrients to the root surface. The result should be a higher level of nutrient uptake, and correspondingly improved plant growth and crop yields. Subsequently, research was conducted at two locations, Urbana and St. Charles, Ill., evaluating various combinations of PA and starter fertilizer in bell peppers. At each site, PA at 0.24 ml/plant banded (5 × 5 cm) in combination with starter fertilizer (114N–240P–160K mg/plant) had a positive effect on plant growth, increasing shoot dry mass 8% and 11%, respectively, compared to starter fertilizer alone. There was a positive yield response to PA at St. Charles, but not at Urbana. At St. Charles, fruit production increased 14%, while yields increased 9% by applying PA as a greenhouse transplant soak (16.4 ml PA/2.0 L water per 512 plants in five applications) in conjunction with banded (5 × 5 cm) starter fertilizer (114N–240P–160K mg/plant). Tissue analysis at both locations showed various degrees of nutrient absorption enhancement. However, the physiological basis for PA-induced increases in plant growth and crop yields are not clear.
Effect of Irradiance Level and Paclobutrazol on Reducation of Leaf Damage in Begonia × cheimantha
Authors: Yoon Beyounghan , Lang Harvey J.
Published: February 2019

Begonia × cheimantha (Christmas or Lorraine begonia) is a popular holiday crop in Europe, with certain cultivars having outstanding postharvest characteristics. Its commercial production in the southern United States has been limited by the occurrence of mottled leaf chlorosis and necrosis, apparently due to environmental stress. In this study, B. × cheimantha `Emma' was grown in the fall in a glass greenhouse at College Station, Texas, under either 0%, 60%, or 87% polyethylene shade cloth. Leaf chlorosis and necrosis was very severe on plants grown in full sun (≈650 mol·m–2·s–1), with slight chlorosis on plants under 60% shade. Plants under full sun, however, were more compact, flowered earlier, and had shorter peduncles with more flowers than those grown under shade. Reducing the vegetative long-day treatment period from 7 to 4 weeks had no effect on leaf damage development. Plants treated with paclobutrazol were shorter and had less leaf damage than untreated plants. Leaves of treated plants had a relatively higher concentration of soluble protein, chlorophyll, and enhanced activities of ascorbate peroxidase (AsA), dehydroascorbate (DHA) reductase, and monodehydro-ascorbate (MDHA) reductase than untreated plants. For Texas growing conditions, these preliminary studies indicate that B. × cheimantha should be grown under reduced light intensities, with excessive height and leaf damage being controlled with growth retardants such as paclobutrazol.
Prefinishing Strategies for Flowering Petunia × hybrida Vilm.
Authors: Warner Ryan M. , Erwin John E.
Published: February 2019

Petunia × hybrida Vilm. `Purple Wave' and `White Storm' were grown under different lighting treatments for different lengths of time at different stages of development during the first 4 weeks after germination. The objective of the experiment was to identify the effects of photoperiod and stage of development on date of anthesis and plant form at anthesis. Seedlings were transplanted from 25-cm3 “plugs” into 85-cm3 cell-packs prior to treatment initiation. Plants were grown under ambient photoperiod (April, St. Paul, Minn.) at 20 ± 1 °C before and after treatments. Lighting treatments were 4 weeks of either 9-h ambient light (SD), ambient light plus 100 μmol·m–2·s–1 continuous light (CT) provided by high-pressure sodium lamps, or varying combinations of weeks of SD and CT. After 4 weeks of treatment, plants either remained in cell-packs, were transplanted into 10-cm pots (one plant per pot), or 19-cm pots (three plants per pot), and grown until anthesis. Data collected included anthesis date, leaf number below the first flower, lateral shoot number, and flower bud number. A single week of CT was sufficient to induce flowering in `White Storm'. `Purple Wave' plants did not flower in response to lighting during the first 2 weeks of development. `Purple Wave' plants grown under CT during weeks 3 and 4 flowered with a lower leaf number than if grown in SD for all 4weeks. Consequences of these findings with respect to prefinishing seedlings and scheduling crops of different container sizes will be discussed.
Cyclamen Flower Development in Response to Temperature
Authors: Karlsson Meriam , Werner Jeffrey
Published: February 2019

Commercially plug-produced Cyclamen persicum `Miracle Salmon' were transplanted into 10-cm pots 15 weeks from seeding and placed at 16 °C. The irradiance was 10 mol/day per m2 during a 16-h day length throughout the study. Three weeks from transplant, the plants were placed at 8, 12, 16, 20, or 24 °C. At the time of temperature change, flower buds were first visible. Time to first open flower decreased with increasing temperature to 20 °C. On average, the cyclamens grown at 20 °C required 60 ± 4.5 days from transplant (165 days from seeding) to first open flower. There was no difference in rate of flowering for the plants grown at 16 or 24 °C (74 ± 9.5 days from transplant). Cyclamens grown at 12 °C required on average 28 more days and cyclamens grown at 8 °C, 45 more days to first open flower compared to plants grown at 20 °C. There was no difference in number of leaves per plant (55 ± 14.4). However, the plants grown at 24 °C had significantly larger leaves and total leaf area per plant (1060 ± 235 cm2) than plants in the other temperature treatments (585 ± 104 cm2). The number of flowers and buds per plant was 45 ± 10.6 for plants grown at 16, 20 or 24 °C. Significantly less flowers and buds were produced by plants grown at 12 °C (34 ± 7.9) or 8 °C (17 ± 3.7).
Effect of High Temperatures on the Postharvest Flowering of Specialty Floral Crop Species
Authors: Williams Millie S. , Starman Terri Woods , Faust James E.
Published: February 2019

Flower growers experience decreased consumer satisfaction with plant species that cease flowering during the summer. The objective of this experiment was to characterize the heat tolerance of four specialty floral crop species in order to predict their summer performance in the different climatalogical regions of the United States. The effect of increasing temperatures on the duration of postharvest flower development was determined for Ageranthemum frutescens `Butterfly' and `Sugar Baby', Brachycome hybrid `Ultra', and Sutera cordata `Snowflake'. Plants were grown in a 18 °C greenhouse until marketable with foliage covering the container and flowers distributed evenly across the plant canopy. Plants were then placed in a phytotron to determine their heat tolerance. Temperature set points of 18, 23, 28, and 33 °C were delivered serially at 2-week intervals, starting at 18 °C. Plants were then returned to 18 °C after the 33 °C treatment. Immature flower bud, mature flower bud, flower and senesced flower numbers were collected once per week. Sutera `Snowflake', and Brachycome `Ultra' had the greatest flower number at the 23 °C temperature, decreasing in the 28 °C environment. Argeranthemum `Butterfly' and `Sugar Baby' had greatest flower number at 28 °C, but flowers were smaller and of lower quality than at 23 °C. Flower development of all cultivars ceased at 33 °C, but when plants were returned to the 18 °C production greenhouse, flower development resumed. According to normal average daily temperatures in Knoxville, Tenn., Ageranthemum frutescens `Butterfly' and `Sugar Baby' would flower until mid-June, while Brachycome hybrid `Ultra' and Sutera cordata `Snowflake' would flower until mid-May.
Mulch and Fertilizer Application Method Influence on Plant Growth in Winter Annual Plantings
Authors: Mirabello R.A. , Einert A.E. , Klingaman G.L. , McNew R.W.
Published: February 2019

A winter planting of pansies, Viola × wittrockiana Gams, was established in existing landscape beds to determine mulch type and fertilizer application method influences on plant growth. Two cultivars, `Bingo Blue' and `Bingo Purple', were planted in beds containing four different mulches (cottonseed hulls, cypress wood, pine bark, pine straw). A split application of fertilizer by three application methods (granular, liquid, time-release) was applied at planting for plant establishment and in the spring to encourage new growth. Fertilizer was applied either below the mulch on the soil surface or over the mulch surface. Cottonseed hulls, cypress wood, and pine bark delayed soil warming in the spring and the effectiveness of all fertilizers. The use of time-release fertilizer below all mulches improved growth. Pine straw allowed soil temperatures to rise and fertilizer to increase plant dry weight accumulation. Rapid decomposition of pine straw resulted in a 0.55-unit decrease in soil pH and increases in soil nitrogen and EC values.
Assessment of Biologically Converted Swine Waste as a Fertilizer Source in Container Production
Authors: Flinn Cindy L. , Campbell Ray , Bilderback Ted E.
Published: February 2019

Swine waste (SW), the by-product of North Carolina's booming hog industry, is one of the state's most underutilized resources. Currently, SW is used to grow coastal bermuda hay, a “disposal” crop with little to no economic value. Use of SW by commercial growers as fertilizer would reduce the need to dispose of SW and could reduce the overall input of nutrients into the environment. Our objectives were to determine: plant growth characteristics of SW, the effects of SW on leachable forms of nitrogen, and the physical effects of SW in a pine bark media. To avoid pathogens, we used SW (BionSoil™) that had been biologically digested as part of a proprietary SW treatment process (Bion Technologies, Inc.). Liners of `Rose Madness' petunia, `Skogholm' cotoneaster, `Girard's Red' azalea, and `Wilson's Yellow' daylily were planted in 3.8-L plastic pots that contained one of the following (by volume): 10% SW:90% pine bark, 20% SW:80% pine bark, 30% SW:70% pine bark, or pine bark (control) amended with 3.6 kg of 23-4-8 controlled release fertilizer (CLF), 3.6 kg dolomitic limestone, and 330 g micronutrient fertilizer per m3. Shoot dry weights were determined for all species at harvest. Root dry weights were obtained for cotoneaster and daylily. Leachate nitrogen and pH was determined periodically throughout the 22-week study. By the 14th week, nitrogen and potassium deficiencies were identified on plants growing in SW-amended media. Those treatments were subsequently topdressed with a corrective application of 9 g of 23N–4P–8K CRF. Generally, SW can produce plants similar to short-term CRF without the need for supplemental micronutrients or lime Root biomass was greater in SW media than in the control. A mid-season application of a N–P–K fertilizer may be necessary.
Comparison of Nodular Efficiencies Between Partridge Pea and Soybean Using Acetylene Reduction
Authors: Barry Lisa M. , Dana Michael N.
Published: February 2019

Legumes are grown as nurse crops in agriculture because they increase soil microbial life and productivity. Native legumes have potential in ecological restoration to mimic the benefits found in agriculture plus they enhance the restored ecosystem. This study was initiated to compare the growth rates, nodulation characteristics, and nitrogen fixation rates of a native versus a non-native legume. The two legumes were partridge pea (Cassia fasciculata); a native, wild, annual legume and soybean (Glycine max `Century Yellow); a domesticated, agricultural, annual legume native to Asia. Plants were grown for 11 weeks in pots containing silica sand and received a nitrogen-free Hoagland's nutrient solution. Beginning at week 12, plants were harvested weekly for four consecutive weeks. Nodulated root systems were exposed to acetylene gas and the resulting ethylene amounts were measured. The two legumes exhibited significant differences in nodule size and shape and plant growth rate. In soybean, nodules were large, spherical, and clustered around the taproot while in partridge pea, nodules were small, irregularly shaped, and spread throughout the fibrous root system. Soybean plants had a significantly faster growth rate at the onset of the experiment but partridge pea maintained a constant growth rate and eventually exceeded soybean plant size. In spite of these observed differences, partridge pea and soybean plants were equally efficient at reducing acetylene to ethylene. These results indicate partridge pea has the potential to produce as much nitrogen in the field as soybean. Native legumes such as partridge pea deserve further research to explore their use as nurse crops in agricultural or restoration regimes.
Effects of Decreasing Temperature and Photoperiod on Carbohydrate Reserve Accumulation and 14C-Photosynthate Partitioning in Apple
Authors: Wang Z. , Huang K. , Mahmoud H. , Quebedeaux B.
Published: February 2019

Carbohydrate reserves are major substrates for cold hardiness and respiration during winter and for early growth during the following season for most woody plants. In apple, carbohydrate reserve accumulation occurs mainly in late summer and autumn as temperature and photoperiod decrease. However, information on the response of reserve carbohydrate accumulation and photosynthate partitioning into sorbitol, sucrose, and starch in apple to decreasing temperature and photoperiod is limited. One-year-old `Gala' apple plants were grown in controlled environments at 26 °C and 16-h photoperiod for 50 d and then either remained in 26 °C/16 h or were subjected to a lower temperature and shorter photoperiod for 28 d that resulted in four treatments of 26 °C/16h (HT/LD), 26 °C/8h (HT/SD), 13 °C/16h (LT/LD), 13 °C/8h (LT/SD). Newly fixed 14C-photosynthates and reserve carbohydrates were analyzed in leaves, stems, and roots. Leaf photosynthesis and plant growth parameters were also examined. The LT treatments inhibited plant shoot growth and leaf initiation rates while SD treatments had little additive effect. Plants with LD treatments had greater specific leaf weight, but decreased photosynthetic rates compared to SD regimes. A decrease in temperature altered partitioning of newly fixed 14C-photosynthates into sorbitol, sucrose, and starch and carbohydrate accumulation in various plant organs. Low temperature effects were modified by photoperiod.
Plum Tomato Cultivar Evaluation Using Microirrigation
Authors: Howe T.K. , Csizinszky A.A.
Published: February 2019

Plum tomato (Lycopersicon esculentum Mill.) cultivars were evaluated in a full-bed mulch, microirrigation management system. Yield and horticultural characteristics were assessed for four entries, `Marina', `Spectrum 882', `Supra', and `Veronica', during Spring and Fall 1997. Harvested marketable fruit were separated by size into extra large, large, medium, and small categories. Spring: Total marketable yields from three harvests combining all fruit sizes ranged from 46.6 t·ha–1 for `Supra' to 57.1 t·ha–1 for `Veronica'. `Veronica' produced significantly higher total yield than the other three cultivars. There were no significant differences among the cultivars in yield of extra large (range: 2.3 to 2.9 t·ha–1) or large (range: 11.4 to 13.0 t·ha–1) fruit. Only `Veronica' (22.7 t·ha–1) and `Supra' (18.9 t·ha–1) were significantly different from each other in the yield of medium fruit. Veronica' produced significantly more small fruit (19.2 t·ha–1) than any other cultivar. Cull fruit yields ranged from 11.1 t·ha–1 for `Veronica' to 16.9 t·ha–1 for `Supra', which was significantly greater than the other cultivars. Fall: Total marketable yields from six harvests were not significantly different among the cultivars, ranging from 22.0 t·ha–1 for `Spectrum 882' to 31.4 t·ha–1 for `Marina'. Extra large fruit yields ranged from 2.0 t·ha–1 for `Supra' to 6.3 t·ha–1 for `Marina', the only cultivars significantly different from each other. There were no significant differences among the cultivars in yields of large (range: 7.9 to 13.8 t·ha–1), medium (range: 8.7 to 13.8 t·ha–1) or small fruit (range: 2.7 to 3.4 t·ha–1). Cull fruit yields ranged from 37.2 t·ha–1 for `Supra' to 47.4 t·ha–1 for `Veronica'. Cuticle cracking (rain check), black shoulder and nipple-tipped blossom ends were the primary defects in the fall. `Marina' and `Veronica' produced significantly more cull fruit than either `Supra' or `Spectrum 882'.
Study of the Regular and High Application of Water with Drip Irrigation in Asparagus
Authors: Fontes Adán Fimbres , Contreras Raúl Leonel Grijalva , de Jesus Valenzuela Ruiz Manuel
Published: February 2019

Asparagus production in the past years has been increasing very rapidly and now totals 5000 ha. The main problem in this zone is the depletion of the aquifer (22 m in static level) and it is important to use of this resource rationally. During 1997, a experiment of drip irrigation in asparagus (first year planted) was conducted. Three treatments were applied: 100%, 133%, and 166% of the evaporation from a pan evaporation type A. The crop coefficient (Kc) applied was 60%. The results of the statistical analysis indicated that the best treatment was 166% (246.13 cm of total water applied) with a height of plant of 1.17 m, and the lowest height of plant was for the 100% (0.87 m) with 121.97 cm of total water applied.
Endogenous Rhythm in Flowers of Stone Fruits
Authors: Orosz-Kovacs Zsuzsanna , Faust Miklos , Borhidi Attila , Szabo Laszlo Gy. , Farkas Agnes
Published: February 2019

It is known that the success of pollination of entomogam, autosterile stone fruits depends on attractiveness of flowers, pollen, and nectar production. In addition to this a complete harmony is necessary between the pollen donor and receiver in the volume of intrafloral secretion, chemical composition, and timing of appearance of attractants. Our investigation shows that the daily production in stone fruits follows a set pattern. The 4 × 6-h rhythm (secretion four times, 6 h apart per day) usually indicates homogamy, whereas a 2 × 12 periodicity indicates dichogamy. Successful pollination is unlikely when endogen rhythm of two cultivars is asynchronized.
Floral Scent Production in Antirrhinum majus
Authors: Bennett Natalie , Dudareva Natalia
Published: February 2019

Despite the economic importance of floral scent for plant reproduction, little is known about the molecular mechanisms of floral scent production. Floral scent is often a complex mixture of low-molecular-weight compounds that are mainly distributed within three groups: fatty acid derivatives, benzenoids, and isoprenoids. Esters of such compounds are the most widespread type. Headspace analysis in combination with gas chromatography and mass spectrometry of volatiles emitted from snapdragon flowers revealed that methyl benzoate is one of the major components of the `Maryland True Pink' genotype. The activity of novel enzyme S-adenosyl-l-methionine:benzoic acid carboxyl methyltransferase (BAMT), which catalyzes the methyl esterification of benzoic acid, was analyzed in different floral tissues and at different stages of flower development. It has been found that BAMT activity is highest in petals, both upper and lower lobes, and very low or absent in other floral tissues and leaves. No detectable BAMT activity was found in flower buds 1 day before flower opening. During the lifespan of the flower the level of BAMT activity in petal tissue increases gradually and remains high in old flowers.
A Leaf Bud Development Scale for Rabbiteye Blueberry
Authors: NeSmith D. Scott , Krewer Gerard , Williamson Jeffrey G.
Published: February 2019

Crop vegetative and reproductive development are frequently divided into stages to describe progression of development. Such a description is useful in denoting developmental differences between cultivars, for making crop management decisions based on growth stages, and for clear communication among individuals concerned with research, management, and production of the crop. We have developed such a scale for leaf bud development in rabbiteye blueberry (Vaccinium ashei Reade). Our scale has six stages briefly described as follows: 1) dormant bud; 2) early green tip; 3) late green tip; 4) unfolding stage; 5) mouse-ear stage; 6) fully opened bud. Categorizing buds in this manner has proven useful in comparing rates of leaf development between cultivars and in response to winter chilling. The stages appear to be relevant to highbush blueberries (V. corymbosum) as well.
Clone and Growth Season Effects on Seven Carbohydrate-related Components and Their Correlation in Sweetpotato
Authors: Xiang Yu , Collins Wanda W.
Published: February 2019

Approximately 50% of the world's total sweetpotato output is used for producing starch or starch-derived products and for animal feeding. Knowledge of cultivar and environmental effects on carbohydrate-related components and the correlation among these components is essential for improving the raw products utilization and providing an expanded market for sweetpotato. The objective of this study was to investigate the variation of amylose content and β-amylase activity as well as their correlation with other starch-related components. Dry matter, starch, total sugar, amylose and phosphate content, β-amylase activity, and raw starch digestibility were evaluated for 20 advanced selections in 2 years. Significant clone variation was detected for all seven components. Significant growth season effects were found for amylose and sugar content, β-amylase activity, and starch digestibility. β-amylase activity has a negative correlation with starch (r = –0.57, P ≤ 0.001) and dry matter (r = –0.39, P ≤ 0.05). Starch digestibility has a negative correlation with amylose (r = –0.37, P ≤ 0.05) and phosphate content (r = –0.35, P ≤ 0.05).
Dormancy-breaking Studies on Echinacea angustifolia
Authors: Sari Ali O. , Morales Mario R. , Simon James E.
Published: February 2019

Echinacea is a medicinal plant native to North America. It was used extensively by native Americans in the treatment of their ailments. It is presently one of the most popular medicinal plants in the United States. Its popularity has created a large market demand for the roots and foliage of the plant. The gathering of echinacea from the wild is leading to the reduction of native populations and the destruction of its genetic diversity. Cultivation of medicinal echinaceas is hindered by a low seed germination. Dormancy breaking studies were done on freshly harvested seeds of Echinacea angustifolia. Seed lots were placed under light at a constant temperature of 25 °C and at alternate temperatures of 25/15 °C for 14/10 h, respectively. Germination was more rapid and uniform and percent germination higher at 25 °C than at 25/15 °C. Seed tap-water soaking, dry heating, and sharp heating alteration did not increase germination. The application of 1.0 mM ethephon (2-chloroethylphosphoric acid) increased seed germination to 94% at 25 °C and 86% at 25/15 °C. Untreated seeds gave 65% germination at 25 °C and 11% at 25/15 °C. The application of 2500 mg·L–1 and 3500 mg·L–1 of GA to dry seeds and 2500 mg·L–1 to seeds that have been soaked under tap water and then dried increased germination to 82%, 83%, and 83% at 25 °C and 64%, 78%, and 64% at 25/15 °C, respectively.
Fresh-cut Mango Fruit Slices
Authors: Limbanyen Arunya , Brecht Jeffrey K. , Sargent Steven A. , Bartz Jerry A.
Published: February 2019

Preparation and handling procedures for fresh-cut mango slices were developed using `Tommy Atkins', `Haden', and `Palmer' mangoes. Fruit with yellow flesh color (no green color remaining) were optimum maturity for fresh-cut in terms of maintenance of acceptable appearance, texture, and taste; riper fruit developed flesh breakdown and more browning. Postharvest life of fresh-cut mango at 5 °C was 8 to 10 d with no evidence of chilling injury and was limited by flesh browning and loss of firmness. Respiration rates ranged from 32 to 40 mg CO2/kg per hr and ethylene production was typically ≤0.1 μl·kg–1·hr–1. The SSC changed little during storage, while pH varied from 3.5 to 4.8 and TA typically declined by 30% to 40%. Peeling to a depth of at least 2 mm and trimming flesh near the stem scar was necessary to minimize browning. Imported fruit that had been heat-treated for insect quarantine showed more severe browning than Florida fruit that had not been heat-treated. Preparation in aseptic conditions and dipping fruit in a 100 ppm NaOCl solution at pH 7 before and after peeling protected against decay during storage but dipping in chlorine after slicing without removal of excess liquid resulted in flesh translucency and breakdown. Dipping in 1% CaCl2 solution had no effect on flesh firmness (Instron) or browning. Storage in an unvented plastic clamshell container, which developed an atmosphere of 2.25% CO2 plus 19% O2, did not improve shelf life, but a MA of 10% CO2 plus 10% O2 was subjectively judged to slow browning and softening and resulted in no off flavor compared to air storage.
Quality of `Solo' Papaya after Irradiation Treatment and Ripening
Authors: Miller W.R. , McDonald R.E.
Published: February 2019

Papaya (Carica papaya L.) imported into the United States must be certified free of infestation by unwanted pests. Irradiation has been suggested as a potential quarantine treatment for papaya. A study was conducted to characterize fruit quality and condition at two stages of maturity and exposure to irradiation treatment. `Solo' papaya grown in Belize was transported in refrigerated sea van containers to Florida. Fruit showing no yellow color or one-quarter yellow color were irradiated at 0.6 kGy, held at 25 °C until ripe, and evaluated for quality and condition attributes. Green peel papaya treated with irradiation developed peel injury and had uneven ripening of pulp tissue following storage. Development of peel or pulp color was not affected by irradiation. Fruit should show one-quarter yellow peel color to avoid irradiation-induced peel damage. Irradiation may be a viable quarantine treatment for papaya that can be applied to fruit at the source of offshore production or on arrival at a facility in the United States.
`Betasweet', Carrot Designed for Flavor, Nutrition, and Health
Authors: Pike Leonard M.
Published: February 2019

`BetaSweet' is a new “designer” carrot that was conceived as a research project with the objective to create a new high-quality vegetable with unique characteristics. The gene responsible for purple or maroon color in carrots is a natural one and has been around for many years. Carrot breeders have discarded carrots that occasionally segregated to this color because orange has been the preferred traditional color. In 1989, three carrots grown from Brazilian seed were observed to have a blotchy maroon color mixed with the normal orange. Within two generations of breeding effort, I had obtained a few carrot roots with near-complete maroon exterior color and orange interior. The contrast of orange and maroon was very attractive in carrots cut as coins or sticks. The maroon and orange color would serve as the perfect way to identify and promote this new variety. Several additional generations were required using extensive laboratory testing for low terpenoids (strong carrot flavors), high sugars, high carotene, and crispy texture. Thousands of carrot roots were analyzed and selected for those qualities and for the dark maroon exterior and orange interior colors. The few best for those characteristics were intercrossed, and re-selected for their adaptation when grown under Texas climatic conditions.
Induction of Callus from Seedling Explants of Citrus macrophylla W. Rootstock
Authors: Guzman S. , Jimènez J. , FarÌas J. , Salazar C. , Hernández M. , Michel A.
Published: February 2019

Citrus macrophylla is an important citrus rootstock for Mexican lemon (Citrus aurantifolia S.). This study was conducted to select explant type and to optimize cultural requirements for induction callus of C. macrophylla in vitro. The explants tested were leaf, epicotyl, cotyledon, and root segments excised under sterile conditions from 4-week-old nucellar seedlings. The various medium comprising either basal of Murashige and Skoog (MS) or Murashige and Tucker (MT) salts suplemented with various concentrations of plant growth regulators, including naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-furfurylaminopurine (kinetin) were used for the establishment of the explants. All cultured explants initiated callus from the cut ends after 2 weeks, when cultured on a modified MT medium suplemented with 6 mg NAA and 0.2 mg kinetin; cotyledon segments were the best explant for callus induction and development (43 mm2). Root segments were the lowest explants for callus induction.
Evaluation of Industrial Peach Cultivars
Authors: Contreras Raúl Leonel Grijalva , de Jesus Valenzuela Ruiz Manuel , Fontes Adan Fimbres , Carbajal Arturo Lopez , Gonzalez Rogelio A. Juarez
Published: February 2019

Sixteen industrial peach cultivars from Brazil and `Flordagold' on `Nemaguard' rootstock were planted at a 5 × 5-m spacing in 1986. The best cultivars were `Cap de Bosc', `Petisco', `Diamante', and `Magno', with yields of 32.8, 28.1, 27.6, and 27.2 t/ha, respectively. `Flordagold' yielded 16.1 t/ha. That maturation period was from 21 June to 19 Aug. The average fruit weight was 80 to 176 g, and soluble solids were 13.1 to 16.1 °Brix. `Diamante' is the recommended cultivar because of its dual utility (table and industrial). `Diamante' is characterized by its yellow fruit with stick seed and an average fruit weight of 176 g. It matures in mid-June. One negative characteristic is that the fruit is prone to oxidation, manifesting in a stain. One advantage in growing this cultivar as an industrial product is a reduced need for labor. These results were validated on a 35-ha farm during 1997.
Three New Peaches and a Nectarine for the Southeastern United States
Authors: Okie W.R.
Published: February 2019

Four new varieties have been released from the USDA–ARS Stone Fruit Breeding program located in central Georgia. All are adapted to the humid Southeastern U.S. climate. `Rubyprince' is an early yellow-fleshed peach with excellent size, firmness, and color. The slow-softening fruit ripens in early June at Byron, about with `Dixired', but is slightly lower chilling (about 800 h below 45 °F). `Blazeprince' is a very firm yellow-fleshed peach with a solid red blush that ripens in late mid-season between `Harvester' and `Redglobe'. It is susceptible to bacterial spot disease similar to `O'Henry'. It requires about 850 chill hours. `Southern Pearl' is a large white-fleshed, mid-season peach with very good acid flavor and medium firmness. It ripens about with `Harvester' or `Redhaven'. Chilling requirement is only about 650 h, similar to `Springcrest'. `Juneprincess' nectarine ripens in about the same season as `Southern Pearl' and produces large, attractive, firm fruit that is less prone to rain cracking than many nectarines. Skin color is bright red, typical of California nectarines, with yellow flesh. Chilling requirement is about 850 h.
Dry Weight Partitioning among Roots, Shoot Bottoms and Tops, and Leaves of Hydrangea macrophylla Cuttings Rooted in Coal Bottom Ash or Peat: Perlite Media Containing Four Levels of Dolomitic Limestone
Authors: Pitchay Dharmalingam S. , Myers Susan , Bearce Bradford C.
Published: February 2019

Terminal tip cuttings of hydrangea (Hydrangea macrophylla Thunb. `Blaumeise Lace Cap') were rooted in 100% coal bottom ash (CBA) sieved through 2-mm mesh or 1 peat: 1 perlite (v/v) containing 0, 3, 6, or 18 g·L–1 of dolomitic lime on 13 July 1997. Rooting performance of the terminal cuttings was monitored weekly for 5 weeks. The pH values were 7.0–7.8 (100% CBA media), 6.3–6.9 (peat:perlite, 18 g·L–1 lime), 6.0–6.5 (peat:perlite, 6 g·L–1 lime), 4.2–5.2 (peat: perlite, 3 g·L–1 lime), and 3.6–5.2 (peat:perlite, 0 g·L–1 lime). Leaf tissue Ca was higher in 100% CBA than that in peat:perlite media after the 2nd week, implying that uptake from the media may have occurred. Total fresh weight of the rooted cuttings increased significantly over 5 weeks and, at week 5, the highest cutting fresh weights were in peat:perlite media with 3, 6, or 18 g·L–1 of lime. No significant differences in shoot tip fresh and dry weights were observed among peat:perlite media, but these were reduced in 100% CBA. Root dry weight and root quality indices were greater in peat:perlite media with 3, 6, and 18 g·L–1. The poorer rooting of hydrangea cuttings in CBA was attributed to the supraoptimal pH range and the substantially lower air capacity (5.25% by volume) compared to that of peat:perlite (15.1%). The superior rooting in peat:perlite media with lime may have been due to the favorable pH range.
Enhanced Growth of Amaryllis (Hippeastrum hybridum) Seedlings in Horse Manure Medium
Authors: Palispis Norma R.
Published: February 2019

An experiment was conducted to compare the growth of amaryllis seedlings in the following media: pure horse manure, 1:1 garden soil–horse manure (v/v), and 1:1 garden soil–wood shavings (v/v). Final values for fresh weight increment, dry weight, leaf area, leaf area index, leaf length increment, bulb width increment, leaf area ratio, and crop growth rate were significantly highest and lowest in horse manure and 1:1 garden soil–wood shavings, respectively. Net assimilation rate, relative growth rate, and moisture content were similar for all treatments.
Use of Digital Analysis of Radicle Extension of Marigold Seedlings as an Early Indicator of Seed Vigor
Authors: Oakley Kay , Geneve Robert , Siriwitayawan Gunching , Kester Sharon
Published: February 2019

Several seed vigor tests were conducted on Marigold `Little Devil Flame' and correlated with digital analysis of radicle extension. Seed from a single lot was deteriorated by the accelerated aging (AA) method at 41 °C for 24 and 72 h. Seed moisture content of unaged seed was 15.23%, mildly aged seed (24-h AA) was 40.77%, and moderately aged seed (72-h AA) was 52.85%. After AA treatment, all seeds were dried to near 15% moisture. Vigor level was assessed 7 days after AA treatment by standard germination and soilless-mix plug emergence tests according to the Association of Official Seed Analysts Rules for Testing Seed. The standard germination test revealed an 84.5% germination for unaged seed, 49.5% germination for mildly aged seed, and 28.5% germination for moderately aged seed. The plug emergence test showed an 88.9% normal emergence for unaged seed, 65.28% germination for mildly aged seed, and 9.72% germination for moderately aged seed. Additionally, the radicle of seedlings established under standard germination conditions was digitally analyzed after 4 days. According to digital analysis, average radicle length for unaged seed was 2.10 cm, 1.91 cm, for mildly aged seed, and 1.27 cm for moderately aged seed. Radicle length after 4 days showed an R2 of 0.81 when regressed against standard germination and an R2 of 0.99 with seedling emergence tests. These results suggest that digital analysis of radicle extension could provide a sensitive, reproducible test for seed vigor.
Nitrogen Acquisition Efficiency of Ericoid Mycorrhizae in High-bush Blueberry (Vaccinium corymbosum L.) Plants
Authors: Yang Wei Qiang , Goulart Barbara L. , Demchak K.
Published: February 2019

In laboratory and growth room experiments, protease activity among a diverse group of ericoid mycorrhizal fungi (isolated from two native and two commercial blueberry sites) was screened via a sensitive fluorescent assay and the efficiencies of mycorrhizal symbionts to use organic (a protein) and inorganic N were determined. There were differences in extracellular protease activity among mycorrhizal isolates within the same genera. Two isolates from a native blueberry site showed the highest extracellular protease activity. Plants inoculated with these two isolates produced more dry weight as compared to the control or plants inoculated with other isolates with lower protease activity when protein was used as the sole nitrogen source. These results suggested that some of the mycorrhizal isolates from native blueberry sites might be more efficient in acquiring soil organic N than those isolated from commercial blueberry sites. This possibility was further examined by using 15N and the results from 15N labeling will be discussed. Our study indicated that it was possible to isolate and identify ericoid mycorrhizal fungal strains which might be useful to increase the host's ability to utilize soil organic N sources.
Impact of an Open Trellis on Canopy Growth, Light Interception, Yield, and Leaf Physiology of Red Raspberry (Rubus idaeus)
Authors: Klauer Stephen F. , Cameron J. Scott , Chen Chuhe
Published: February 2019

After promising results were obtained with an open-style split trellis (two top wires) in its initial year, two new trials were established in 1997 in northwest (Lynden) and southwest (Woodland) Washington. For the split trellis, actual yields were 33% (machine-picked 1/2 season) and 17% (hand-picked) greater, respectively, for the two locations compared to the conventional trellis (one top wire). In Woodland, canes from the split trellis had 33% more berries, 55% more laterals, 69% more leaves, and 25% greater leaf area compared with the conventional trellis. Greatest enhancement of these components was in the upper third of the canopy. Laterals were also shorter in this area of the split canopy, but there was no difference in average total length of lateral/cane between trellis types. Total dry weight/cane was 22% greater in the split trellis, but component partitioning/cane was consistent between the two systems with fruit + laterals (43%) having the greatest above-ground biomass, followed by the stem (30% to 33%) and the leaves (21% to 22%). Measurement of canopy width, circumference, and light interception showed that the split-trellis canopy filled in more quickly, and was larger from preanthesis through postharvest. Light interception near the top of the split canopy was 30% greater 1 month before harvest with 98% interception near the top and middle of that canopy. There was no difference between the trellis types in leaf CO2 assimilation, spectra, or fluorescence through the fruiting season, or in total nitrogen of postharvest primocane leaves.
Oxygen Consumption and Carbon Dioxide Production Rates of `Red Gold' Nectarines as Affected by Gas Composition and Storage Temperature
Authors: Botero-Omary Maria , Testin Robert F. , Rushing James W. , Rajapakse Nihal C.
Published: February 2019

The effects of gas composition and temperature on both the O2 consumption (RRO2) and CO2 production (RRCO2) rates of `Red Gold' nectarines were investigated. Three temperatures (0, 10, and 20 °C) and six gas combinations of initial O2 (1%, 5%, and 20%) and CO2 (0 and 15%) with the balance N2 were used. Triplicate glass jars containing two fruits each were flushed with the respective certified gas mixtures and stored in environmental chambers maintained at 0, 10, and 20 °C. Head space O2 and CO2 concentrations were monitored until O2 levels dropped to 1% or less. Both RRO2 and RRCO2 showed significant increases (P < 0.05) as temperature increased from 0 to 20 °C at the gas concentrations tested. The RRO2 increased slightly (P < 0.05) as initial O2 concentration increased while showing no changes at the range of initial CO2 concentrations used in the study. For RRCO2, no significant changes (P < 0.05) were observed as gas concentrations varied at constant temperatures. This information is useful in establishing empirical models for modified atmosphere packaging predictions.
Evaluation of Carrot Cultivars Over Multiple Locations for Suitability of Quality and Harvest Characteristics
Authors: Kelley William Terry , Reid James , Franks Randy , Reed Rick , Bateman Anthony , Phatak Sharad
Published: February 2019

Fresh-market carrots (Daucus carota L. sativus) have only been produced on any significant scale in Georgia since the early 1990s. Because most of the southeast U.S. carrot production is on muck-type soils, production practices had to be established for carrot production on mineral soils. Included in the establishment of these practices was the evaluation of varieties to find those of suitable yield. Additionally, these varieties had to possess low bolting, sufficient quality, and produce a sufficient top to be harvested mechanically. Many of the varieties produced in western states were not suitable for production in Georgia. After several years of testing under experiment station conditions, plots were established on farms at three separate locations. Plantings were established 1 Oct. and 24 Nov. 1997 in Jeff Davis County and on 4 Nov. 1997 in Wayne County. Plots consisted of three twin rows on a 1.-m bed with 35 cm between twin rows. Plots were a minimum of 6 m in length. Normal fertility and cultural practices were used. Evaluations of external color, length, overall marketability, smoothness, and top sufficiency were made on 27 Mar., 8 May, and 30 May, respectively. A total of 36 varieties were examined in replicated plots. Although there were some differences in smoothness and color, there were greater differences among varieties for marketability, and particularly length and top sufficiency. Several varieties were identified that would be suitable for production in Georgia.
Molecular Markers Linked to Heat Tolerance of Broccoli
Authors: Yang Yau-Wen
Published: February 2019

A heat-tolerant broccoli cultivar was derived from the cross between two inbred lines. One inbred line of S7 is selected from a local cultivars in southern Taiwan, and the other of S6 is from the progenies of hybrids between broccoli and white flowering kale. The heat tolerance of this cultivar is believed to be inherited from the white flowering kale, which has been grown in southern Taiwan for a long period of time and has the characteristic of heat tolerance. Several molecular markers that may be linked to the heat tolerance were indentified and may be able to be used in the future breeding program of broccoli and its related varieties.
Effect of Planting Method, Mulch, and Rowcover Combinations on Yield and Fruit Quality of `Earliqueen' Muskmelon
Authors: Handley David T. , Koller Sheri I. , Dill James F.
Published: February 2019

Three techniques to enhance the development and yield of `Earliqueen' muskmelon, including transplanting, plastic mulch, and rowcovers, were applied in all combinations to determine which practice or practices offered the most beneficial effects on early maturity, and total marketable yield. Using transplants (two true leaf stage) as opposed to direct seeding had the greatest effect on increasing early yield. Black plastic mulch also significantly increased early yield. Rowcovers did not provide an overall increase in early yield, although the highest early yield was achieved from the transplant/mulch/rowcover combination. Black plastic mulch had the greatest effect on total marketable yield. Transplanting also significantly increased total yield. A slight increase observed for rowcover treatments was not significant. The combination of transplanting/plastic mulch/rowcover produced the highest marketable yield of any treatment. Direct seeding combined with no mulch produced the lowest yields and the lowest percent of marketable fruit. Under the conditions of a prolonged, cool, cloudy spring, followed by a hot, dry summer, the use of transplants and black plastic mulch provided significant increases in marketable yield of `Earliqueen' muskmelons. Rowcovers did not provide significant yield effects, probably due to low light levels during the early growth period.