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  • Author or Editor: C. S. Clark x
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Rabbiteye (Vaccinium ashei Reade) and southern highbush (mostly V. corymbosum L.) type blueberry selections were evaluated in regional trials at five locations. Entry × location interactions (E × L) were significant for all traits in the rabbiteye type and all except plant productivity, plant volume, Julian date of 50% ripe fruit, and berry weight at harvest 3 in the southern highbush type. Despite the significant interactions, selection FL80-11 and `Gulfcoast' were the earliest flowering rabbiteye and southern highbush entry, respectively, at each location. Significant E × L for plant volume and yield suggests that adaptation to the local environment is important in the selection of potential cultivars. Fruit quality traits appear less affected by environment than fruit production traits for the entries tested.

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Abstract

This study examined the leaf anatomy and water stress of Prunus insititia L. cv. Pixy grown in aseptic culture before and after transfer to the greenhouse and grown in a layerage bed in the field. The depth of palisade cells was significantly less in aseptically cultured plantlets than in greenhouse transfererred plants, and less in greenhouse transferred than in field-grown plants. Percent mesophyll air space was greater in plantlet than in plant leaves. Upper or lower leaf epidermal cell length of plantlets of field grown plants was not significantly different. Stomatal frequency for plantlet leaves was significantly less about 150 stornata per mm2) than that of plant leaves (300 stornata per mm2). Excised plantlet leaves lost greater than 50% of total leaf water content within 30 min; excised greenhouse leaves lost 50% after 90 minutes.

Open Access

Fruit zone leaf removal is a vineyard management practice used to manage bunch rots, fruit composition, and crop yield. We were interested in evaluating fruit zone leaf removal effects on bunch rot, fruit composition, and crop yield in ‘Chardonnay’ grown in the U.S. state of Georgia. The experiment consisted of seven treatments: no leaf removal (NO); prebloom removal of four or six leaves (PB-4, PB-6), post–fruit set removal of four or six leaves (PFS-4, PFS-6), and prebloom removal of two or three leaves followed by post–fruit set removal of two or three leaves (PB-2/PFS-2, PB-3/PFS-3). Although leaf removal reduced botrytis bunch rot and sour rot compared with NO, effects were inconsistent across the two seasons. Fruit zone leaf removal treatments reduced titratable acidity (TA) and increased soluble solids compared with NO. PB-6 consistently reduced berry number per cluster, cluster weight, and thus crop yield relative to PFS-4. Our results show that post–fruit set fruit zone leaf removal to zero leaf layers aids in rot management, reduces TA, increases soluble solids, and maintains crop yield compared with no leaf removal. We therefore recommend post–fruit set leaf removal to zero leaf layers over no leaf removal if crops characterized by relatively greater soluble solids-to-TA ratio and reduced bunch rot are desirable for winemaking goals.

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Sweet potato virus disease (SPVD) is the most devastating virus disease on sweetpotato [Ipomoea batatas (L.) Lam] world wide, especially in East Africa. However, weather it is present in the U.S. is unknown. SPVD is caused by co-infection of sweetpotato feathery mottle virus (SPFMV) and sweetpotato chlorotic stunt virus (SPCSV). Presence of two other potyviruses, sweetpotato virus G (SPVG) and Ipomoea vein mosaic virus (IVMV) has also been confirmed in the U.S. Sweet potato leaf curl virus (SPLCV), a whitefly (Bemisia tabaci) transmitted Begomovirus, also has the potential to spread to commercial sweetpotato fields and poses a great threat to the sweetpotato industry. The U.S. collection of sweetpotato germplasm contains about 700 genotypes or breeding lines introduced from over 20 different countries. Newly introduced sweetpotato germplasm from foreign sources are routinely screened for major viruses with serology and graft-transmission onto indicator plants (Ipomoea setosa). However, a large portion of this collection including heirloom cultivars or old breeding materials has not been systemically screened for these major sweetpotato viruses. In this study, a total of 69 so-called heirloom sweetpotato PI accessions were evaluated for their virus status. We used Real-time PCR to detect five sweetpotato viruses, including four RNA viruses (SPCSV, SPFMV, SPVG, and IVMV) and one DNA virus (SPLCV). A multiplex Real-time RT-PCR system was developed to detect three RNA viruses (SPFMV, SPVG, and IVMV). Preliminary data indicated that about 15% of these heirloom sweetpotato germplasm carried at least one of these viruses tested. Details on virus infection status will be presented.

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Strawberry (Fragaria ×ananassa Duch.) was grown for two seasons with microirrigation. Preplant fertilizer treatments of zero, one, two, three, and four times the basic N and K rate of 17 and 15 kg·ha–1, respectively, were applied each season. Additional N and K were applied twice weekly through the microirrigation system at 1.12 and 0.92 kg·ha–1·day–1, respectively. Total marketable fruit yield and marketable fruit per plant were not affected by preplant fertilizer rate. The percentage of marketable fruit increased with increased preplant fertilizer to the 51N–45K (three times basic rate) kg·ha–1 rate the first season. Average fruit weight increased the first season but decreased the second season with increased preplant fertilizer. Plants were larger the first season in treatments receiving preplant fertilizer.

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Sixteen field-located drainage lysimeters (each 60 cm wide, 2.44 m long, 60 cm deep) designed specifically for determination of water requirements for fruiting strawberry production (season - Oct to April) were installed in 1986. Each lysimeter was equipped with individual micro-irrigation and drainage collection systems automated for minimal management input. Initially, computer control (using a low-cost microcomputer) was used to continuously check switching-tensiometers located in each lysimeter and apply irrigation water as needed, A drainage suction (-10 MPa) was applied continuously to simulate field drainage conditions. Manually-installed lysimeter covers were used to protect the plots from interference from rainfall when needed, Initial irrigation application treatments were set at four levels of soil moisture tension controlled by tensiometers and were measured using flow meters for each lysimeter. This paper will discuss problems that were experienced with the initial setup (difficulty in measuring actual application amounts, tensiometer and computer control, elimination of rainfall interference, uniformity of irrigation application, and salinity in the rooting zone) and the modifications (pressurized reservoir tanks, construction of motorized rain-out shelter, micro-irrigation emitters used, and fertilization program) which have been made to overcome them,

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Each year a wide variety of new cultivars and species are evaluated in the National Cut Flower Trial Programs administered by North Carolina State University and the Association of Specialty Cut Flower Growers. Stems of promising and productive cultivars from the National Trial Program were pretreated with either a commercial hydrating solution or deionized (DI) water and placed in either a commercial holding solution or DI water. Over 8 years, the vase life of 121 cultivars representing 47 cut flower genera was determined. Although there was cultivar variation within each genus, patterns of postharvest responses have emerged. The largest category, with 53 cultivars, was one in which a holding preservative increased vase life of the following genera and species: acidanthera (Gladiolus murielae), basil (Ocimum basilicum), bee balm (Monarda hybrid), black-eyed susan (Rudbeckia hybrids), campanula (Campanula species), celosia (Celosia argentea), common ninebark (Physocarpus opulifolius), coneflower (Echinacea purpurea), coral bells (Heuchera hybrids), feverfew (Tanacetum parthenium), foxglove (Digitalis purpurea), ladybells (Adenophora hybrid), lisianthus (Eustoma grandiflorum), lobelia (Lobelia hybrids), obedient plant (Physostegia virginiana), ornamental pepper (Capsicum annuum), pincushion flower (Scabiosa atropurpurea), pinkflower (Indigofera amblyantha), seven-sons flower (Heptacodium miconioides), shasta daisy (Leucanthemum superbum), sunflower (Helianthus annuus), snapdragon (Antirrhinum majus), sweet william (Dianthus hybrids), trachelium (Trachelium caeruleum), and zinnia (Zinnia elegans). Hydrating preservatives increased the vase life of four basils, coral bells, and sunflower cultivars. The combined use of hydrator and holding preservatives increased the vase life of three black-eyed susan, seven-sons flower, and sunflower cultivars. Holding preservatives reduced the vase life of 14 cultivars of the following genera and species: ageratum (Ageratum houstonianum), false queen anne's lace (Ammi species), knotweed (Persicaria hybrid), lisianthus, pineapple lily (Eucomis comosa), sneezeweed (Helenium autumnale), yarrow (Achillea millifolium), and zinnia. Hydrating preservatives reduced the vase life of 18 cultivars of the following genera and species: feverfew, lisianthus, ornamental pepper, pineapple lily, seven-sons flower, shasta daisy, sneezeweed, sweet william, sunflower, trachelium, yarrow, and zinnia. The combined use of hydrating and holding preservatives reduced the vase life of 12 cultivars in the following genera and species: false queen anne's lace, feverfew, pincushion flower, sneezeweed, sunflower, trachelium, yarrow, and zinnia. Data for the remaining 50 cultivars were not significant among the treatments; these genera and species included beautyberry (Callicarpa americana), black-eyed susan, blue mist (Caryopteris clandonensis), calendula (Calendula officinalis), campanula, cleome (Cleome hasserliana), common ninebark, dahlia (Dahlia hybrids), delphinium (Delphinium hybrids), flowering peach (Prunus persica forma versicolor), heliopsis (Heliopsis helianthoides), hemp agrimony (Eupatorium cannabinum), himalayan honeysuckle (Leycesteria formosa), hydrangea (Hydrangea paniculata), larkspur (Consolida hybrids), lily of the nile (Agapanthus hybrid), lisianthus, lobelia, ornamental pepper, pineapple lily, scented geranium (Pelargonium hybrid), sunflower, sweet william, and zinnia.

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The Florida horticulture industry (vegetables, ornamentals, citrus, and deciduous fruit), valued at $4.5 billion, has widely adopted microirrigation techniques to use water and fertilizer more efficiently. A broad array of microirrigation systems is available, and benefits of microirrigation go beyond water conservation. The potential for more-efficient agricultural chemical (pesticides and fertilizer) application is especially important in today's environmentally conscious society. Microirrigation is a tool providing growers with the power to better manage costly inputs, minimize environmental impact, and still produce high-quality products at a profit.

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