bluuebunny/crossref_metadata_2025 huggingface dataset:
Cultural Practices that Impact Stone Fruit Quality
Authors: Southwick* Stephen
Published: February 2019

Quality of stone fruit is defined by fruit size, color, firmness, flavor, shape, general appearance, adhesion and size of the stone and fruit surface characteristics (e.g. fuzz, abrasions, pest damage). Cultural practices, such as pruning, nutrition, irrigation, growth regulator usage and pesticide applications can influence these quality characteristics to a greater or lesser extent. Adequate potassium nutrition can improve soluble solids and fruit size in plums. Excess nitrogen fertilization can soften peaches. Well-timed calcium sprays are thought to improve the firmness of sweet cherries, as are applications of gibberellin. Ethylene synthesis inhibitor usage can alter the timing of ripening, reduce early fruit drop and improve storage. Irrigation scheduling is a tool that can be used to regulate final fruit size and firmness, as well as time of maturation. Selective pruning is used to structure a tree's architecture for improved light penetration to improve fruit size and color. These and other production practices will be discussed in relation to how they affect fruit quality in stone fruit.
Yield and Fruiting Characteristics of 28 Selections in the Kentucky Pawpaw Cultivar Trial
Authors: Pomper* Kirk W. , Masabni Joseph G. , Layne Desmond R. , Crabtree Sheri B. , Peterson R. Neal , Wolfe Dwight
Published: February 2019

The pawpaw [Asimina triloba (L.) Dunal] has great potential as a new fruit crop. A pawpaw variety trial was established in Fall 1995 in Princeton, Ky. as a joint Kentucky State Univ.-Univ. of Kentucky research effort with the objective to identify superior varieties for Kentucky. A randomized block experimental design was used with 8 replicates of 28 grafted scion selections on seedling rootstock. Cultivars being tested included Middletown, Mitchell, NC-1, Overleese, PA-Golden, Rappahannock, Shenandoah, Sunflower, Susquehanna, Taylor, Tay-two, Wells, and Wilson. The other 15 clones were selections from the PawPaw Foundation. In 2002 and 2003, the following parameters were examined: tree survival, trunk cross-sectional area (TCSA), average fruit weight, total fruit harvested per tree, average fruit per cluster, total yield per tree, and yield efficiency. In 2003, 54% of the trees had survived, with `Susquehanna' (13%) showing the poorest survival. Based on TCSA, most selections displayed excellent vigor, with the exception of the selections: 5-5 and `Overleese'. Average fruit weight was greatest in 1-7-2 (194 g), 1-68 (167g), 4-2 (321 g), 5-5 (225 g), 7-90 (166g), 9-58 (176 g), 10-35 (167 g), NC-1 (180 g), `Sunflower' (204 g), and `Shenandoah' (168g), with the smallest fruit in `Middletown' (70 g), `Wells' (78 g), and `Wilson' (88 g). The selections `Wilson' (81), `Middletown' (75), and `Wells' (70) had the greatest average number of fruit per tree, whereas 4-2 (9), 5-5 (17) and 8-20 (15) the fewest. Yield efficiency and average fruit per cluster also varied greatly among selections. Several pawpaw selections in the trial show promise for production in Kentucky.
Prohexadione-Ca in Fruit Trees: Modes of Action of a Multifunctional Bioregulator
Authors: Rademacher* Wilhelm
Published: February 2019

APOGEE and REGALIS have recently been introduced in a number of countries for use in pome and other fruit trees. These products contain 27.5% and 10% of prohexadione-Ca (ProCa), respectively. As a result of inhibiting excessive vegetative growth, less summer and dormant pruning is required, the ratio between vegetative growth and fruit formation is improved, and crop protection is facilitated due to the reduction of tree row volume and a more open canopy. Additionally, a lowered incidence of diseases such as fire blight and scab is observed, which is not due to a direct bactericidal or fungicidal effect of the compound. Further, the compound may reduce fruit drop early in the season. Prohexadione is a structural mimic of 2-oxoglutaric and ascorbic acid. Therefore, distinct dioxygenases are blocked, which require these compounds as a co-substrate. Such enzymes catalyze late steps in gibberellin biosynthesis. After treatment with ProCa, less growth-active gibberellins are formed and treated plants remain more compact. ProCa also affects ACC oxidase, another dioxygenase. The resulting reduction of ethylene formation, in addition to the availability of more assimilates for fruit growth, is most likely the cause of reduced fruit drop. 2-Oxoglutaric acid-dependent dioxygenases are also involved in the metabolism of flavonoids and their phenolic precursors: In shoots of apples and pears, ProCa causes considerable changes by inhibiting flavanone 3-hydroxylase. Convincing evidence is now available that ProCa triggers pathogen resistance by inducing the formation of 3-deoxyflavonoids, in particular luteoforol, with phytoalexin-like properties. Morphoregulatory effects caused by ProCa are only of secondary relevance for the reduction of disease incidence.
Effects of Saline Water and Two Types of Plastic Mulch on Physiology and Yield of Bell Pepper Plants
Authors: Morales-Garcia* Dagobiet , Stewart Katrine A.
Published: February 2019

In order to examine the effects of saline water (0.2, 1.5, 4.0, 6.5 and 9.0 dS·m-1) without or with plastic mulch (black or green infrared transmitting) on the physiology and yield of bell peppers (Capsicum annuum L. var. Red Night), plants were drip irrigated and grown in greenhouse conditions. Salinity did not significantly decrease the rate of photosynthesis until fruit set after which irrigation with 6.5 and 9.0 dS·m-1 reduced rates by 35%-38% and during fruit development by 50% compared with the control treatment. Plants receiving 4.0 dS·m-1 had significantly lower (30%) photosynthetic rates than the control during fruit development. Stomatal conductance decreased as the rate of salinity increased which in turn affected transpiration. No consistent differences in photosynthesis, stomatal conductance and transpiration rates were obtained with or without plastic mulch. The marketable yield was negatively affected as salinity increased having being reduced by 17%, 64%, 96%, and 100% for saline treatments compared with the control. The number of fruit of fruit per plant was significantly lower at rates of 4.0 dS·m-1 or higher. No significant differences were detected among plastic mulches and non-mulch condition in marketable yield and number of fruits. Water consumption decreased as salinity level increased with decreases of 11%, 20%, 38%, and 52% of the control value. Mulching the soil reduced water consumption by 30% compared with bare soil.
Influence of Various Fertilizers on Vegetative and Fruiting Characters of Cape Gooseberry (Physalis peruviana)
Authors: Chahal* Tanjeet Singh
Published: February 2019

A fertilizer trial was conducted to study the effect of Nitrogen (N), Phosphorus (P), and Potassium (K) on vegetative growth and fruit quality characters in cape gooseberry. The experiment consisting of three levels each of N, P, and K (at 5, 10, and 15 g/plant) along with their interactions was conducted in the experimental area, Dept. of Horticulture, Khalsa College, Amritsar, Punjab during the year 2001-2002. The increasing level of N, P, and K help to increase the plant height, where as application of N and K at 10 g/plant and P at 15 g/plant proved their worth for maximizing fruit size. The total soluble solids level of fruits increased significantly with the increment of N level, whereas in case of P and K the total soluble solids increased upto the moderate level and decreased with the further increment. On the other hand, the acidity per cent followed an increase with the each increasing level of all the fertilizers.
Respiratory Q10 of Lettuce Increases with Increasing Plant Size
Authors: van Iersel* Marc W.
Published: February 2019

Literature reports on the Q10 for respiration vary widely, both within and among species. Plant size and metabolic activity may be responsible for some of this variation. To test this, respiration of whole lettuce plants was measured at temperatures ranging from 6 to 31 °C during a 24-h period. Subsequently, plant growth rate (in moles of carbon per day) was determined by measuring the CO2 exchange rate of the same plants during a 24-h period. Environmental conditions during this 24-h period resembled those that the plants were exposed to in the greenhouse. The measured growth rate was then used to estimate the relative growth rate (RGR) of the plants. The respiratory Q10 ranged from 1.4 for small plants to 1.75 for large plants. The increase in Q10 with increasing plant size was highly significant, as was the decrease in Q10 with increasing RGR. However, growth rate had little or no effect on the respiratory Q10. One possible explanation for these findings is that the Q10 depends on the ratio of growth to maintenance respiration (which is directly related to RGR). The growth respiration coefficient generally is considered to be temperature-insensitive, while the maintenance respiration coefficient normally increases with increasing temperature. Based on this concept, the Q10 for the maintenance respiration coefficient can be estimated as the estimated Q10 at a RGR of zero (i.e. no growth and thus no growth respiration), which was 1.65 in this experiment. Although the concept of dividing respiration into growth and maintenance fractions remains controversial, it is useful for explaining changes in respiratory Q10 during plant development.
Thermal Stability of Pepper Leaf Extracts
Authors: Anderson* Jeff
Published: February 2019

Acute heat stress can denature and aggregate proteins. The objective of this study was to determine how changes in the chemical and physical environment affected high temperature-induced turbidity and precipitation in pepper (Capsicum annuum L.) leaf extracts. High temperature stability of leaf extracts decreased as the tissue concentration increased. Control extracts exhibited a time-dependent change in resistance to turbidity and precipitate development, but the presence of polyvinylpolypyrrolidone stabilized the extracts. Ethylenediamine-tetraacetic acid had a less marked effect on turbidity and precipitation. Solution thermal stability increased as buffer pH increased from pH 6.0 to 7.0 regardless of whether the pH was adjusted before or after tissue extraction. Mannitol strongly stabilized pepper leaf extracts, but a surfactant lowered the thermal stability.
Insights into the Role of Rubisco Activase in Heat Stress-limited Photosynthesis
Authors: Weston* David J. , Weston David J. , Swire-Clark Ginger A. , Baird Wm. Vance
Published: February 2019

Rubisco, the primary enzyme governing carbon assimilation, is dependent upon Rubisco activase. The heat sensitivity of activase, including its expression and thermal stability, varies among species and is considered a key component governing photosynthetic performance in response to moderate heat stress (32-35 °C). However, the Rubsico-Rubsico activase association has yet to be examined among woody plants or varieties within a species, the understanding of which will assist cultivar improvement strategies. Using molecular and physiological techniques to study the role of activase in thermal regulation of photosynthesis, we found that net photosynthesis decreased in Acer rubrum L. `Northwood' at 31°C, whereas the southern variety, A. rubrum `Florida Flame', maintained optimal assimilation rates up to 36 °C. Additionally, the maximal carboxylation rate of Rubisco (Vcmax) at 35 °C was 31.7% lower for Northwood in comparison to Florida Flame. The cloned activase sequences from both cultivars show 97% nucleotide homology and 98% amino acid identity, indicating the potential for similar protein product formation and function. Interestingly, sequence analysis indicates that both cultivars produce at least two isoforms of activase derived from alternative transcript splicing. We will discuss activase mRNA processing and protein isoform abundance in relation to Rubisco kinetic properties as a function of heat tolerance in these two thermally contrasting woody plant genotypes.
Water-holding Polymers: Revisiting Their Role in Bedding Plant Production and Shelf Life
Authors: Frantz* Jonathan M. , Pitchay Dharmalingam S. , Locke James C.
Published: February 2019

There are several commercial materials available that have remarkable hydrating properties and many claim them to be ideal for use in horticulture and deliver water to the roots better than other soilless media. These are often referred to as “hydrogels.” There is general agreement in the literature that the physical characteristics of hydrogels are altered in the presence of divalent cations such as Ca and Mg. Tap water can reduce the water holding capacity by 70% or more. Unfortunately, the literature agrees on little else in terms of the performance of hydrogels. Some of the confusion is caused in part by comparing one type of hydrogel to another but treating all as equal. There has been no mathematical performance evaluation of hydrogel and what affect the environment may play in that performance to predict potential irrigation savings or shelf life extension. In a series of greenhouse and laboratory studies, we have evaluated the physical characteristics of several types of hydrogels and characterized bedding plant performance throughout a typical growth cycle. We measured leaf expansion, water content of the media, root growth, flowering, and fresh and dry masses. We have found little to no differences in the rate of leaf expansion when using hydrogels, but enhanced root growth early in production with the hydrogels. Our results indicated that plant growth was enhanced early in production, but any advantage they may have was lost by the end of production. Plants grown in hydrogels needed irrigation less frequently than those without hydrogel, but the effect was diminished over time. Since the use of the material can add about 15% to the cost of potting media, this data is designed to assist growers in hydrogel use and to determine any benefits of the added costs.
Water-use Efficiency of One-year-old Sweet Cherry (Prunus avium L.) cv. `Rainier' on Dwarfing and Standard Rootstocks, under Well-watered and Water Deficit Conditions
Authors: Zavalloni Costanza , Nikoloudi Adriana , Flore* James A.
Published: February 2019

This study was conducted to determine whether standard and dwarfing sweet cherry rootstocks under water deficit conditions respond differently relative to plant growth and gas exchange parameters, water-use efficiency, and leaf carbon isotope composition. One-year-old potted sweet cherry cv. `Rainier' grafted on the standard rootstock `Mazzard' and on the dwarfing rootstock `Gisela 5' were compared under two different water treatments: 1) well-watered, which received daily 100% of the amount of water lost by ET, and 2) a water deficit treatment, which received 50% of the water applied to the control. Relative shoot growth rate, leaf emergence rate and cumulative leaf area were recorded every three to seven days during the experiment. Leaf net carbon dioxide assimilation rate, stomatal conductance, transpiration rate, internal CO2 concentration, and WUE were measured daily for the duration of the experiment. At the end of the experiment, leaf samples were collected to determine leaf carbon isotope composition. The growth parameters measured were affected similarly in the two rootstocks indicating a similar degree of sensitivity to water deficit in the genotypes tested. Cumulative leaf area was affected earlier by water deficit than relative shoot growth, and leaf emergence rate. Gas exchange parameters were affected earlier than growth parameters. Overall, WUE was not significantly different between dwarfing and standard rootstocks, and did not appear to increase under water deficit condition, indicating that irrigation should be considered as an important practice in sweet cherry orchards, especially when dwarfing rootstocks are selected.
Water Movement in the Root Zone of Strawberry Grown with Plasticulture
Authors: Simonne* Eric , Duval John , Studstill David
Published: February 2019

Visualizing the effect of irrigation volume on water movement in and below the root zone of strawberry (Fragaria ×ananassa) plants may be used to determine when to split irrigation. By injecting blue dye (Terramark SPI High Concentrate) during controlled irrigation events with several drip tapes commonly used by area growers, the objectives of this project were to: (1) determine vertical, lateral and longitudinal movements of wetted zones applied by drip irrigation on a Seffner fine sand soil; (2) describe the shape of the wetted zone for increasing irrigation volumes; and (3) determine the irrigation after which water moves below the root zone. Dye tests consisted in preparing mulched beds with different drip tapes (7 total), injecting dye, irrigating with the selected volume of water (V), digging longitudinal and transverse sections of the raised beds, and taking measurements of vertical (depth; D), lateral (width; W) and longitudinal (L) water movement. Increasing V from 279 to 3353 L/100 m, significantly increased D, W and L. Depth and W responses to V were D = 0.19 V + 26.1 (R2 = 0.80), and W = 0.36 V + 13.5 (R2 = 0.78). Emitter-to-emitter coverage occurred after 4 hours for 30-cm spacing. Based on expected root depths of 20 cm when the strawberry plants are young and 30 cm when they are fully grown, largest V before water moved below the root zone were 325 and 870 L/100 m, which corresponds to typical irrigation times of 1 and 3 hours, respectively. Greater irrigation volumes may reduce water use efficiency and increase the risk of nutrient leaching below the root zone.
English Walnut Production on Marginal Soils
Authors: Edstrom* John P. , Krueger William , Reil Wilbur
Published: February 2019

Orchard hedgerow production systems have been used successfully in fruit and nut crops in California for decades to enhance yield, particularly in the early years of production. English walnuts (Juglans regia) are compatible with hedgerow techniques under prime soil conditions but are thought to require deep well drained soil to be commercially productive. Combining the production techniques of micro-irrigation, close spacing, minimal pruning and frequent fertilization in almonds has improved yield substantially on soils exhibiting a shallow, course textured topsoil underlain with a dense clay layer. Paradox hybrid rootstock (J. regia × J. hindsii) has shown greater tolerance to root lesion nematodes and heavier textured or poorly drained soils than Northern California Black (J. hindsii). Fourteen years of evaluation (1986-99) using `Chandler' and `Howard' Ctvs English walnuts in a replicated field trial on marginal soil has shown that 1) yields of 6700 kg·ha-1 (inshell) are attainable under these substandard soil conditions 2) Paradox hybrid rootstock out-yields Northern California Black by 30% on both cultivars tested, 3) kernels of high commercial quality for can be produced for both cultivars and 4) slip plow soil modifications may not improve tree growth, yield or crop quality in drip irrigated walnut hedgerow plantings.
Nickel Deficiency is Occuring in Orchard Trees
Authors: Wood* Bruce , Reilly Charles , Nyczepir Andrew
Published: February 2019

Nickel (Ni) is an essential nutrient element for higher plants; although, it has generally been ignored. This is because it appeared that Ni deficiency would not likely occur in field situations. This conclusion is because a) Ni content of nearly all soils is thought to be high enough to satisfy plant requirements, and b) plant Ni requirements were thought to be very low. Thus, plant Ni nutriton has been generally ignored. We report here: 1) the discovery of acute Ni deficiency in field plantings of pecan (Carya illinoinensis); 2) the wide variety of symptoms associated with Ni deficient; 3) soil management conditions that cause Ni deficiency; and 4) potential impact of Ni deficiency on management strategies for crops. Observations indicate that Ni deficiencies are occuring on many woody crops in orchard or nursery situations. Evidence indicates that Ni deficiency is likely a factor in many complex disorders of unknown cause affecting a variety of crops. Ni deficiency problems are likely to become increasing common and severe as a result of contemporary management practices. The information presented identifies a need for greater attention to plant Ni nutrition by practitioners of crop husbandry.
Variation in Bioactive Flavonoid Content of Commercial Brands of Orange Juices
Authors: Vanamala* Jairam , Reddivari Lavanya , Yoo Kil Sun , Pike Leonard M. , Patil Bhimanagouda S.
Published: February 2019

Orange juice is an important source of bioactive compounds like flavonoids and the main human dietary source of antioxidant compounds in developed countries. Citrus flavonoids possess chemo-preventive and anti-inflammatory properties as well as the ability to lower cholesterol and modulate the immune function. In this study, we examined flavonoid content of “concentrated” (n = 12) and “Not-From Concentrate (NFC)” (n = 14) commercial orange juices by an HPLC method to investigate the brand to brand differences and differences within the brand (various types). Correlation between flavanonoid content (mg) and price per unit volume was also evaluated. Significant (P = 0.05) differences among the brands were observed in the flavanoid content of both NFC and concentrated orange juices. Total flavonoid content was significantly higher in concentrated juices compared to the NFC juices. However, higher content of didymin was found in NFC juices. Within the brand, no significant differences in the total flavonoid content were observed in juice types containing antioxidant vitamins compared to the juice types devoid of these vitamins. Price did not correlate with the total flavonoid content for either NFC (r = 0.057) or concentrated (r = -0.49) orange juices. Hesperidin was the major flavonoid and followed by narirutin and didymin. Their content (mg/100 mL) in concentrated and NFC juices ranged between 18-55 (Hesperidin); 3-8 (narirutin); and 1-2.5 (didymin), respectively. This study provides valuable information on flavonoid composition of orange juices commonly available in the US market.
Evaluation of Hot Pepper Cultivars Grown on Guam
Authors: Takai* Glenn , Marutani Mari
Published: February 2019

Hot peppers (Capsicum sp.) were introduced to Guam and other Mariana Islands and became a “necessary” ingredient of local cuisine. Seven hot pepper accessions, including four local cultivars, were grown in calcareous soils on Guam and evaluated for total yield, marketable yield, the number of fruit, and weight of fruit. `Hot Beauty', a Taiwan cultivar, produced the highest total and marketable yields. `Group Zest', another Taiwan cultivar, was the earliest maturing cultivar and produced the largest fruits. `Guafi', a local cultivar, was the latest maturing cultivar. Consumer preference for hot pepper is being studied as fresh market and as processed hot sauce.
Recent Successes in the Use of Natural Herbal Remedies for the Treatment of Intra-uterine Fibroids Without Surgery
Authors: Olapade* Ebenezer Oluwafemi , Olapade Ebenezer Oluwafemi , Olapade Clement Akinlayo Oluwadayomi , Olapade Christiana Oluwabusayo , Olapade John Babajide
Published: February 2019

Many physiologically active women after reaching the age of puberty suddenly discover that their menstruation becomes irregular with longer periods of heavier flow. This situation often arise when the womb is empty without conception for a long time. The uterus is found to contain some growing masses of tissues called fibroid which may be tiny, single, many or very big. They could occupy the lumen of the uterus and referred to as intra-uterine fibroids or could develop within the walls of the uterus or on the outside wall of the uterus. They alter the shape and size of the uterus in most cases. Intra-uterine fibroids grow in size and in several cases prevent conception in young women who are eager to get pregnant, thereby leading to frustration, and anxiety. The origin and cause of fibroids is not well understood. Ethno medicinal knowledge refer to fibroids as false pregnancy because women carrying fibroids are thought to be pregnant for several years without delivering the baby. Years of ethno medicinal research at the NARL Specialist Clinic, Ibadan, Nigeria led to the compounding of natural plants which include Calotropis sp, Citrus sp and a few tropical plants that have proved successful as a remedy for intra-uterine fibroids without surgery. The existing fibroid masses within the uterus gradually diminish in size, until they disappear completely The re-growth of fibroid masses within the uterus is suppressed or inhibited This will be helpful in many cases where women who have not reached menopause can have free uterine cavity devoid of fibroids especially when they are not pregnant for several years. The problem of infertility due to fibroids can also be avoided.
EST Analysis for the Study of Cold Stress in Blueberry (Vaccinium spp.)
Authors: Dhanaraj* Anik L. , Slovin Janet P. , Rowland Lisa J.
Published: February 2019

To gain a better understanding of changes in gene expression associated with cold stress in the woody perennial blueberry (Vaccinium spp.), a genomics approach based on the analysis of expressed sequence tags (ESTs) was undertaken. Two cDNA libraries were constructed using RNA from cold acclimated (mid winter conditions when the plants are cold stressed) and non-acclimated (before they received any chilling) floral buds of the blueberry cultivar Bluecrop. About 600 5'-end ESTs were generated from each of the libraries. Putative functions were assigned to 57% of the cDNAs that yielded high quality sequences based on homology to other genes/ESTs from Genbank, and these were classified into 14 functional categories. From a contig analysis, which clustered sequences derived from the same or very similar genes, 430 and 483 unique transcripts were identified from the cold acclimated and non-acclimated libraries, respectively. Of the total unique transcripts, only 4.3% were shared between the libraries, suggesting marked differences in the genes expressed under the two conditions. The most highly abundant cDNAs that were picked many more times from one library than from the other were identified as representing potentially differentially expressed transcripts. Northern analyses were performed to examine expression of eight selected transcripts and seven of these were confirmed to be preferentially expressed under either cold acclimating or non-acclimating conditions. Only one of the seven transcripts, encoding a dehydrin, had been found previously to be up-regulated during cold stress of blueberry. This study demonstrates that analysis of ESTs is an effective strategy to identify candidate cold-responsive transcripts in blueberry.
Writing Across the Curriculum: Where does Horticultural Science Fit In?
Authors: Anderson* Neil O. , Hoover Emily , Zambreno Karina , Gillman Jeff
Published: February 2019

In Fall 1999, the Univ. of Minnesota implemented a writing intensive requirement for undergraduates. As part of the requirement, students must take one writing intensive (WI) course in their major. Formal and informal writing in critical draft review are key components of intensive writing. The Dept. of Horticultural Science offers an Environmental Horticulture Major which currently has only one writing intensive course in its curriculum. Teaching faculty (13/14), responsible for 21 courses in the curriculum, were interviewed and syllabi were reviewed to gather information on what types of writing are currently being assigned and to discuss where WI courses should be placed in the Environmental Horticulture curriculum in the future. The majority of classes utilize formal writing and the majority of faculty review, or are willing to review, a draft of an assignment. Informal writing assignments are less common, indicating a deficient area of the curriculum. With slight modifications, many classes in the curriculum can meet the requirements to become WI. Faculty agreed that WI courses should be placed in upper level, smaller classes that place less emphasize on production techniques or plant identification.
Triploid Miniwatermelon Production in the Southeastern United States, 2003
Authors: Schultheis* Jonathan R. , Hassell* Richard L. , Jester Wilfred “Bill” R. , Maynard Donald N. , Miller Gilbert A.
Published: February 2019

Demand for triploid watermelons has outpaced the demand for diploid watermelons in the United States in recent years. The size of most triploid watermelons sold in U.S. markets is from 6 to 9 kg. Recently, a new produce item, seedless watermelons weighing about 1.8 to 3.6 kg, have been introduced and created excitement in the produce industry. Several vegetable seed companies have developed proprietary miniwatermelon hybrids. Syngenta Seeds and Seminis Vegetable Seeds have received the most publicity, with the PureHeart and Bambino brands being featured in the 15 June 2003 New York Times. The 2003 season was the first year that cultigens (cultivars and advanced lines) were generally available. At least four trials were conducted in the southeastern United States to evaluate yields and quality of mini-watermelons; Bradenton, Fla., Ediston, S.C., Charleston, S.C., and Kinston, N.C. Cultural practices and the number of cultigens varied among locations (9 to 17). Fruit less than 3.6 kg that yielded best in all locations were `Petite Perfection' (Syngenta) and RWT 8149 (Syngenta). Other cultigens that yielded well in at least one location were; `Precious Petite' (Syngenta), `Vanessa' (Sunseeds), ZG 8905 (Zeraim Gedera), SR 8103 WM (Sunseeds), SW 8002 (Southwestern), and HA 5130 (Hazera). Rind thickness varied from 6 to 25 mm and soluble solids ranged from 10 to 13%, depending on location and cultigen. New cultivars will be made available in 2004. Key characteristics that seem important to overall success in the market of the triploid miniwatermelon is consistent quality. This includes high yields of uniform sized fruit from about 1.6 to 3.8 kg; high soluble sugars (11% to 13%); and fruit with bright red, crisp flesh with a thin rind that endures shipping.
Effects of Mulch Type and Planting Date on Tomato Earliness within a High Tunnel
Authors: Jett* Lewis , Read Andrew
Published: February 2019

High tunnels are passive solar greenhouses that are used to extend the traditional growing season for many horticulture crops. Growing conditions within a high tunnel are significantly different from growing conditions encountered in field production. Tomatoes (Lycopersicon esculentum Mill.) are wells suited for high tunnel culture having an upright growth habit and a significant economic premium for precocious harvest. The objective of this research was to investigate three planting dates (15 Mar., 30 Mar., and 10 Apr.) and three mulch types (black plastic, bareground, and clear plastic) with or without row covers, for early tomato production within a high tunnel in the Central Great Plains. High tunnels increased the average daily temperature by ≈6 °C. Early planting (i.e., mid- to late March) resulted in significantly earlier yield (i.e., early July). Using clear plastic mulch increased total marketable yield, but was not significantly different from black plastic. Row covers and plastic mulch are necessary for early tomato production. Row covers are specifically necessary for frost protection, but can be removed when the risk of frost has decreased.
Mapping Phytophthora Root Rot Resistance in Red Raspberry using SCARs, CAPs, AFLPs, and RGAs
Authors: Pattison* Jeremy A. , Samuelian Suren K. , Weber Courtney A.
Published: February 2019

RAPD and AFLP markers were first used to construct a molecular map in a BC1 red raspberry population consisting of 70 individuals that segregated for Phytophthora root rot resistance. RAPD markers linked to root rot resistance were identified by bulk segregant analysis and through QTL anlaysis. Two common genomic regions were identified by both analyses and were estimated to explain ≈50% of the phenotypic variation. RAPD markers flanking the QTL were cloned and made into sequence specific markers for potential use in marker assisted selection. In addition to the linked markers, RAPDs spread throughout the linkage map were also sequenced and developed into either SCARs, CAPs, or codominant SSRs. Attempts were made to locate red raspberry resistance gene analogs using degenerate primers designed on conserved regions encoding known resistance genes. Results on the type and map position of identified RGA's and selection efficiency of linked markers analyzed in red raspberry cultivars of characterized root rot resistance will be discussed.
Molecular Analysis of Fruit Size Regulation in Apple
Authors: Malladi* Anish , Hirst Peter
Published: February 2019

Fruit size is a commercially valuable trait. Although several factors are known to affect fruit size in apple, insights into the molecular aspects of its regulation are lacking. Our research aims to understand fruit size regulation using a combination of approaches. Analysis of a large fruited mutant of `Gala', `Grand Gala' (GG), showed that it was 40% heavier than `Gala' at harvest. Increase in size of GG fruit was caused by an increase in the cell size apparent at full bloom. Flow cytometry revealed the presence of multiple levels of ploidy (up to 16C) in GG during early fruit development. Increase in ploidy of GG is hypothesized to be due to endoreduplication, a process normally absent in apple. Endoreduplication is a modification of the cell cycle where DNA replication is not followed by cell division, resulting in increased DNA content accompanied by increased cell size. To understand if the cell cycle is altered in GG, four key cell cycle regulators, MdCDKA1, MdCDKB1, MdCYCB2 and MdCYCD3 have been partially cloned from apple using RT-PCR and RACE. As cell number at the end of the cell division phase is correlated with fruit size at harvest, expression analysis of these genes can provide valuable insights into their role in the regulation of cell number and fruit size. Analysis of cell cycle gene expression in GG may provide key insights into the altered molecular regulation that leads to endoreduplication in the mutant. Parallel approaches being employed to study whether environmental and cultural factors regulate fruit size through an influence on the cell cycle will also be discussed.
Expanding the Seasonal Availability of `Valencia' Sweet Orange via Somaclonal Variation
Authors: Grosser* Jude W. , Chandler J.L. , Goodrich R.M.
Published: February 2019

Sweet orange (Citrus sinensis L. Osbeck) is the most horticulturally important and widely grown Citrus species in Florida and worldwide, and `Valencia' is the most important cultivar for processing. Frozen concentrate orange juice has been the primary product of the Florida and Brazilian industries, but recently there has been a strong shift to not from concentrate (NFC) product in Florida. The higher quality NFC has a greater consumer appeal, and brings a higher market price. The development of higher quality oranges with expanded maturity dates will facilitate this change and should increase the competitive ability of the Florida industry. No true sweet orange cultivars have been developed by conventional breeding due to biological impediments, and alternative methods to obtain genetic variation are being investigated, including studies of somaclonal variation. We have produced nearly 1000 somaclones of `Valencia' sweet orange using organogenesis, somatic embryogenesis, and protoplasts. Following several years of fruit evaluation, early and late maturing high quality somaclones have been identified based on juice analytical data (brix, acid, ratio, juice percentage, juice color, and lbs. solids). These clones have also performed exceptionally in taste panel evaluations comparing them with the traditional mid- and late-season cultivars. Second generation trees of the most promising clones have been propagated for further evaluation, and superior processing clones will be released to the Florida industry in the near future. An overview of this program including pilot plant juice quality data and taste panel results will be presented.
Transfer of Powdery Mildew Resistance from Brassica carinata to B. oleracea
Authors: Tonguc* Muhammet , Griffiths Phillip D.
Published: February 2019

Powdery mildew is a fungal disease of crucifers, caused by Erysiphe polygoni D.C. and it can be problematic during seed increase in green-houses. Crosses were made between Brassica carinata (Ethiopian mustard) accession (PI 360883) and B. oleracea cultivars `Titleist' and `Cecile' to transfer resistance to powdery mildew to B. oleracea germplasm. It was not possible to obtain interspecific hybrids between Ethiopian mustard and B. oleracea through natural seed set. However, interspecific hybrids and backcross one (BC1) progenies were produced via embryo rescue following sexual crosses. Four interspecific hybrid plants were produced with the aid of embryo rescue from cultured pistils with B. carinata as the maternal parent, and their interspecific origin was confirmed through plant morphology and analysis of RAPD polymorphisms. No interspecific hybrids were obtained when `Titleist' was used as a maternal parent. Interspecific hybrid plants were male sterile and they were used as maternal parents to produce BC1 plants. Twenty one BC1 plants were obtained through natural seed set and embryo rescue, although embryo rescue was not necessary to produce first backcross generation plants. When tested in greenhouse with powdery mildew, all interspecific hybrids and eight of the BC1 plants were resistant to the disease. Crosses are being made to produce BC2 plants with 2n = 18 chromosomes for introgression of the resistance in B. oleracea.
Common Smut Infection Reduces Sweet Corn Ear Processing Quality
Authors: Blatchford Sarah , Clough* George H. , Hamm Philip B.
Published: February 2019

Impact of natural infection of common corn smut (Ustilago maydis) on processing characteristics of three F1 hybrid sweet corn (Zea mays L.) cultivars was evaluated in a two-year study with early and late spring-planting dates. At harvest maturity, size and location of galls were recorded and quality characteristics measured. Galls on the lower stalk, upper stalk and tassel reduced fresh weight and diameter of husked ears while galls on the base of the plant reduced fresh weight only. Ear length was reduced by galls on the upper stalk. As gall size increased from 0 to >10.2 cm. diameter, ear fresh weight and diameter decreased. The presence of galls >10.2 cm diameter reduced ear length. Kernel depth was not affected by size or location of gall. Additional ears of the same three cultivars were sampled from commercial fields planted in mid-season near Walla Walla and Patterson, Wash. Galls located on the upper and lower stalk reduced fresh weight, length, diameter and kernel depth, while galls on the tassel or base had reduced or no effect on these parameters. As gall size increased, fresh weight, length, diameter, and kernel depth decreased.
Critical Tissues for Nutrient Diagnostics and Optimal Nutrients for Enhancing Yield of Processing Carrots
Authors: Pettipas* F. Christine , Lada Rajasekaran R. , Caldwell Claude D.
Published: February 2019

Carrot (Daucus carota L. var sativus) production in Nova Scotia is challenging as carrots are grown under cool temperatures, rainfed conditions, and in mineral soils usually of low fertility. Growers must rely on fertilizer inputs to optimize yields. Excess application can result in high costs and may lead to soil and environmental problems. There is no up-to-date solidly-based, fertilizer recommendation available for carrot production in Nova Scotia. A greenhouse trial was conducted to identify the critical tissue(s) at various growth stages and optimal tissue nutrient concentrations for yield and quality. This will provide a diagnostic tool for assessing plant nutrient health and the opportunity to correct nutrient deficiencies to prevent yield losses, as well as provide an up-to-date fertilizer recommendation. Dicer carrot seeds, variety Red Core Chatenay were grown in sand culture system that used a gravity-fed drip irrigation system. Nine fertility treatments consisting of a complete 20-20-20 plus micronutrients fertilizer was used to deliver at 0, 50, 100, 150, 200, 250, 300, 350, and 400 ppm equivalent of N, P, and K. Soil and plant tissue samples were taken at 4 and 9 weeks and at final harvest at 13 weeks. Critical tissues varied for each element studied at each of the growth stages. Results suggest 0 and 50 ppm treatments did not provide enough fertilizer to obtain maximum growth while plants receiving above 300 ppm were found to be more susceptible to disease. The treatment with 100 ppm N, P, and K was optimal, being significantly higher in yield and quality than all treatments except 150 ppm.
Effects of Cover Crops on Soil Microbial Biomass in Vegetable Cropping Systems
Authors: Selvaraj* Mohan , Ngouajio Mathieu
Published: February 2019

The inclusion of cover crops into cropping systems may influence soil microbial activity which is crucial to sustained crop production. A study was conducted to measure short term effects of summer and winter cover crops on soil microbial biomass carbon (MBC) in a cucumber-tomato rotation system. The experiment was established in Summer 2002 as a factorial of summer cover crops (planted either as fallow or after harvest of cucumbers) and winter cover crops (planted in September). The design was a split-block with four replications. The main plot factor was summer cover crop and consisted of five treatments; sorghum sudangrass fallow (SGF), cowpea fallow (CPF), sorghum sudangrass after cucumber (SGC), cowpea after cucumber (CPC) and bareground fallow (BGF). The sub-plot factor was winter cover crop and consisted of three treatments including cereal rye (CR), hairy vetch (HV) and bareground (BG). In spring of 2003, soil samples were collected in each treatment at 30 days before (30 DBI), 2 days after (2 DAI) and 30 days after (30 DAI) cover crop incorporation. MBC was measured using the chloroform fumigation-incubation method. Both summer and winter cover crops affected soil microbial activity. MBC in the summer cover crop treatments at 30 DBI was 47.7, 51.4, 49.2, 43.7 and 42.5 μg·g-1 soil for SGF, CPF, SGC, CPC and BGF, respectively. At 30 DAI, 113.1, 88.9, 138.5, 105.6, and 109.3 μg·g-1 soil was obtained in SGF, CPF, SGC, CPC, and BGF plots, respectively. Soil MBC was similar at 2 DAI in the summer cover crop treatments. Among winter treatments MBC was similar at 30 DBI and 30 DAI, but significant at 2 DAI with values of 62.8, 53.3, 59.3 μg·g-1 soil for CR, BG, and HV, respectively.
The Effects of Plant Populations on Pickling Cucumber Canopy Dynamics and Yield
Authors: Ngouajio* Mathieu , Hausbeck Mary K. , Sullen Daniel M. , Selvaraj Mohan , Charles Kevin
Published: February 2019

Michigan is the national leader for pickling cucumber production. However, over the last few years growers have witnessed a considerable decline in marketable yield, mainly attributed to fruit rot caused by Phytophthora capsici. Phytophtora develops rapidly under high relative humidity, a situation commonly found with narrow rows. Growers are interested in using wider rows but would like to know if there are any associated yield reductions. This study was conducted in 2003 to measure the effects of cucumber plant populations on canopy dynamics and fruit yield. Cucumbers were grown with between-row spacing of 30.5, 45.7, 61.0, and 76.2 cm, and in-row spacing of 10.2, 12.7, and 15.2 cm. A split-plot design with four replications was used. Row spacing was the main plot factor, and in-row spacing the subplot factor. Soil covered by plant canopy was monitored throughout the growing season using digital image analysis techniques. At harvest, the number of fruits per plant and marketable yield for the different grades were measured. Cucumber canopy remained open during the major part of the growing season when wide rows (61.0 and 76.2 cm) were used. The number of fruits per plant increased from an average of 1.5 fruits at 30.5 cm to 2.0 fruits per plant at 61.0 cm. Further widening of row spacing to 76.2 cm slightly reduced the number of fruits per plant. Therefore, the optimum row spacing would be 61.0 cm if the number of fruits per plant was the only parameter being measured. Cucumber marketable yield was similar with 30.5, 45.7, and 61.0 cm spacing between the rows. With 76.2-cm rows, yield reduced slightly. These results suggest that cucumber plant density can be reduced substantial with limited yield penalty.
Insect Trap Catch Improvement with Light-Emitting Diode Modification
Authors: Chu* Chang-chi , Umeda Kai , Chen Tian-Ye , Simmons Alvin M. , Henneberry Thomas H.
Published: February 2019

Insect traps are vital component of many entomological programs for detection and monitoring of insect populations. We equipped yellow (YC), blue (BC) sticky card (BC) with 530 nm lime green (LED-YC) and 470 nm blue (LED-BC) light-emitting diodes, respectively that increased trap catches of several insect pests. The LED-YC traps caught 1.3, 1.4, 1.8, and 4.8 times more adult greenhouse whitefly Trialeurodes vaporariorum (Westwood), sweetpotato whitefly Bemisia tabaci (Gennadius) biotype B, cotton aphids Gossypium hirsutum (L.), and fungus gnats Bradysia coprophila (Lintner), respectively, compared with standard YC traps. The LED-YC traps did not catch more Eretmocerus spp. than the standard YC traps. Eretmocerus spp. are important B. tabaci parasitoids used in greenhouse biological control programs. For whitefly control in greenhouse the 530 nm lime green LED equipped plastic cup trap designed by Chu et al. (2003) is the better choice than LED-YC trap because it catches few Eretmocerus spp. and Encarsia spp. whitefly parasitoids released for B. tabaci nymph control. The LED-BC traps caught 2.0-2.5 times more adult western flower thrips Franklinella occidentalis (Pergande) compared with the standard BC traps.
Use of Mixture Experiments to Determine the Effect of Counterions of Bicarbonate on Bean (Phaseolus vulgaris L.) `Poncho' in Hydroponics
Authors: Valdez-Aguilar* Luis A. , Reed David Wm.
Published: February 2019

Mixture experiments were used to study the effect of Rb, K, and Na in combination with a number of bicarbonate concentrations on bean plants grown in hydroponics in a controlled environmental chamber. The objective was to separate the cation effect from the bicarbonate effect. The first experiment was a 3-component mixture-amount experiment using various ratios of Rb, K, and Na at 0 and 7.5 mm of bicarbonate. In the 0 mm bicarbonate control, the pure blends were ranked: Rb > Na > K for their effect on reducing shoot dry mass. The high toxicity to the Rb ion was probably due to direct Rb toxicity in addition to any general salinity effect. At 7.5 mm bicarbonate, shoot dry mass was decreased with all the counter-ions compared to the 0 mm bicarbonate control, and their toxicity was ranked: Rb > Na ≈ K. The next series of experiments were 2-component mixture-amount experiments at various ratios of K and Na at 2.5, 5 and 7.5 mm bicarbonate. In the 0 mm bicarbonate control, shoot dry mass decreased with increasing proportions of Na, indicating a specific Na toxicity. The same trend was observed at 2.5 mm bicarbonate. In the 7.5 mm bicarbonate treatment, both Na and K were equally toxic. At low concentration of bicarbonate, the Na is more toxic than the bicarbonate. At higher concentrations of bicarbonate, both Na and bicarbonate exhibit similar levels of toxicity.