Search Results
You are looking at 1 - 10 of 15 items for :
- Author or Editor: Donna Marshall x
- HortScience x
Surviving extremes of climate is a fundamental component of horticultural production and research. The Southern Horticultural Laboratory has weathered many storms including Hurricane Camille and now Hurricane Katrina. The name of the research station has changed twice, both times following massive hurricanes. Before Hurricane Camille in 1969, the station title was the Tung Research Unit. After the devastation of the tung industry by Camille, the research focus changed to blueberries and other small fruit crops with a corresponding name change to Small Fruit Research Unit in 1976. The research objectives expanded to include ornamental research in 2001. Post Hurricane Katrina, the unit was renamed the Thad Cochran Southern Horticultural Laboratory to reflect the station's expanded research mission. This paper chronicles how the station reacted to the devastation of Hurricane Katrina. It also evaluates economic vitality of commodities researched at the station in contrast with storm effects on pecan and the demise of tung production. Katrina produced some temporary interruptions in production but no drastic restructuring of the type experienced with tung production after Camille is anticipated. Hurricanes are inevitable for the Gulf Coast region. Wise planning and implementation of preventative measures to protect horticultural crops and research will determine future success.
A study was initiated in November, 2002 to determine the effects of exposing two Southern Highbush blueberries (Vaccinium corybosum L) to artificial chilling hours on initiation of bud break and advancement of floral and vegetative bud maturity. Plants of `Jubilee' and `Misty' were divided into 2 groups in which one was left outdoors, allowing chilling to occur and accumulate naturally, while the other group was placed in a growth chamber set at a constant artificial temperature of 4 °C. Five plants of each cultivar were then placed into a heated greenhouse after 0, 200, 400, 600, or 800 hours of chilling (total hours of exposure to <5 °C) had accumulated for forcing of flower bud development. The progression of floral bud development of the terminal three buds on five tagged stems was observed at 7-10 day intervals for 30 days. At the end of the forcing period observations were also made on total percent vegetative and floral bud break. Prior to accumulating sufficient chilling requirements, chilling delivery method did not appear to influence the rate of floral bud development since none advanced past stage 3 regardless of chilling regime used. However after chilling requirements were met, flower buds of plants that were allowed to chill naturally developed more quickly than did those chilled by artificial means.
To improve the quality of berries during handling and shipping, blueberry breeders have strived to develop a fruit that is firm in texture. However, some previous studies have suggested that blueberry cultivars with firmer fruit were more susceptible to splitting. This study was conducted to further investigate the correlation between splitting susceptibility and fruit firmness. Various cultivars and selections of rabbiteye (Vaccinium ashei) and southern highbush (interspecific hybrids primarily consisting of V. corymbosum) blueberry were used to determine whether berries displaying higher fruit firmness also have a higher incidence of splitting. Three distinctly different measurements of berry firmness were obtained using two instruments: QTS25 and FirmTech2. Berries were subsequently submitted to laboratory procedures to induce splitting. In general, firmness measured as either deformation (FirmTech2) or modulus of elasticity (QTS25) correlated with splitting tendencies. There are exceptions, however, that need to be further examined.
We evaluated relationships between floral traits of 23 genotypes of southern blueberries and indices of pollination efficiency (fruit set, fruit abortion, seed number, and berry size) for Osmia ribifloris Cockerell, a manageable solitary bee. Flower size in Vaccinium and presumably ovary size were proportional to berry size, except for the tiny blooms of one V. tenellum clone (NC7808), which produce large commercial-sized berries of ≈2 g. Longer-styled blueberry flowers visited by O. ribifloris produced the heaviest berries with the most seeds. Osmia ribifloris reliably pollinated ‘Climax’ and ‘Tifblue’ rabbiteye blueberries. However, the peculiarly misshapen blooms of ‘Premier’ rabbiteye blueberry receive less pollination from O. ribifloris and yield berries containing 25% fewer seeds. Fruit set for these misshapen ‘Premier’ flowers was equivalent to that of intact flowers indicating that this floral polymorphism would not greatly alter cultivar performance. For seven Vaccinium species, wild and cultivated alike, 80% to 100% of a plant’s fruit production depends on efficient cross-pollination by bees such as O. ribifloris.
Calcium is commonly known to affect the developmental processes of many plants, and its role as a major nutrient has been interpreted in terms of its interaction with components of the cell wall and membrane. A 2-year study was conducted to assess the affects of calcium foliar feed fertilization applied at bloom and throughout floral development on the reduction of rain-related splitting in blueberries. Foliar-applied calcium at 0.2% or 0.9% concentration did not successfully decrease splitting in blueberries to a statistical and, more importantly, an economically significant level. Calcium sprays also had no adverse affects on the fruit firmness, quality, or calcium concentrations within the fruit.
The consumption of fresh fruit and vegetables has always been known to provide essential nutrition to mankind and, both anecdotally and clinically, has been linked to the prevention or alleviation of chronic diseases. The muscadine grape, a fruit native to the southeastern U.S., contains numerous phenolic compounds that act as antioxidants and also other compounds, such as resveratrol, that acts as a chemopreventative. The concentrations of these compounds present in the muscadine grape equal or exceed that known for any other small fruit. Fruit of selected muscadine grape genotypes, including breeding lines and cultivars, were evaluated over a 2-year period to assess the existing genetic base for these nutraceutical compounds. Results demonstrated that concentrations of total phenolics, ellagic acid, and resveratrol differ significantly among cultivars and breeding lines. These results suggest that it should be possible to breed for increased concentrations of the health-promoting compounds in muscadine grapes.
Split-resistant and split-susceptible rabbiteye blueberry fruit were evaluated at all stages of development to determine “water uptake thresholds” by soaking in distilled water. Weight increase after soaking was measured, and percent weight gain was calculated to take into consideration the weight increase of the fruit from development. The ratio of percent increase in volume to weight increase resulting from water uptake was calculated. Ratios of percent water uptake to weight increase between split-susceptible ‘Tifblue’ and split-resistant ‘Premier’ blueberries were found to be similar. The split-susceptible ‘Tifblue’ had a 1.6 g/50 fruit increase with a 1.7% water uptake and a ratio of 1.08. ‘Premier’ had a higher weight increase with 3.3 g/50 fruit and also a higher percentage of water uptake at 3.6% providing a ratio of 1.09. Although both absorbed water at a constant rate shown by a linear increase of weight increase over time, ‘Premier’ absorbed a significantly greater amount of water than did ‘Tifblue’ yet remained intact and did not split.
Muscadines are grapes indigenous to the Southeastern United States, and they are highly prized for their unique fruity flavors. Factors including skin color, berry size, skin thickness, flower type, productivity, etc., vary among muscadine grape cultivars, making some cultivars more desirable for fresh market while others are better suited for processing and prodction of juice, jelly, and wine. A muscadine grape research vineyard was established in McNeil, Miss., in 1992 containing 37 named cultivars and numerous breeding lines. Performance of these cultivars was evaluated in 2001–2003 and results of these trials are presented.
Fruit splitting takes place in rabbiteye and southern highbush blueberries when a preharvest rainfall occurs and when fruit are fully ripe or approaching full ripeness. This study was initiated to develop a laboratory method to identify the rain-related incidence of splitting in cultivated blueberries. Multi-year field surveys of select rabbiteye and southern highbush cultivars show that the incidence of rain-related splitting is strongly cultivar dependent. Year to year variations within cultivars reflected yearly differences in ripening times and amounts and timing of rainfall. Laboratory values of forced splitting and field splitting data of three years show a strong correlation indicating that the incidence of fruit splitting can be accurately estimated by laboratory methods. Soaking the berries in distilled water 14 hours at room temperature gives a confident determination of splitting tendencies. Blueberry breeders can use this method to evaluate new potential blueberry cultivars for splitting tendencies. This laboratory method could also be used by geneticists to test selections accurately for splitting tendencies as part of routine screening. This can lead to a long-term goal of reducing splitting susceptible blueberries in commercial plantings.