development on young plants. Flower buds are typically removed from blueberry plants during the first year after planting ( Pritts, 2006 ; Williamson et al., 2004 ; Yarborough, 2006 ). Current recommendations in many states call for hand removal of flowers
Jeffrey G. Williamson and D. Scott NeSmith
The increase in the capitula of zinnia plants (Zinnia violacea Cav.) was investigated by analyzing the production of shoots. The effects of removing the buds for capitula and application of BA on the production of shoots were also evaluated. It took ≈40 to 50 days from the emergence of axillary buds to the opening of the capitula at the apices of the shoots from these axillary buds. The application of BA shortened the number of days for the same process. The difference in the number of days from emergence of the axillary buds to that of the first descendant axillary buds was ≈25. The total number of capitula opened was greater in plants with the bud removal treatment than in intact plants. Chemical name used: (N-phenylmethyl)-1H-purine-6-amine (BA).
Pecan is a highly heterozygous outcrossing species that is normally propagated by grafting or budding onto seedling rootstocks. The four-flap or banana graft is commonly used by growers or researchers because of its high percentage of success, especially when employed by novice grafters. We removed scion buds before grafting in an attempt to delay budbreak, thus providing more time for vascular connections to form before leaf development and its associated demand for water takes place. Removal of buds from the scion wood was successful in delaying bud and leaf development, but did not increase graft success, and in one treatment actually lowered graft success.
Patrick J. Connor
Pecan is a highly heterozygous outcrossing species which is normally propagated by grafting or budding onto seedling rootstocks. The four-flap or banana graft is commonly used by growers or researches because of its high percentage of success, especially when employed by novice grafters. We removed scion buds before grafting in an attempt to delay budbreak, thus providing more time for vascular connections to form before leaf development and its associated demand for water takes place. Removal of buds from the scion wood was successful in delaying bud and leaf development, but did not increase graft success, and in one treatment actually lowered graft success.
K.D. Patten and J. Wang
Percentage of fruiting uprights, fruit set, number of fruit per upright, and flower bud formation of `McFarlin' and `Stevens' cranberries (Vaccinium macrocarpon Ait.) were reduced by removal of old leaves, new leaves, or both on the upright. Results varied slightly, based on which leaves were removed, time of removal, cultivar, year, and bog site. Percentage of fruiting uprights, flowers and fruit per upright, and fruit set were higher on uprights with a terminal bud size >1 mm in diameter in September than for those <1 mm in diameter. Effects were cultivar and site dependent. Terminal bud size of `McFarlin' was negatively related to the subtending number of fruit and positively related to leaf fresh weight of the upright.
Jenny Heringer Vires, Robert Anderson, and Robert Geneve
Purple Coneflower [Echinacea sp. (Asteracea)] is of great value to the horticultural, pharmaceutical, and herbal industry. More research is needed to determine cultural practices that will produce a plant high in biomass and phenolic content, the chemical used for testing the quality of the harvested plant on a percent basis of roots, flowers and vegetative parts. The objective of this experiment is to determine if biomass and phenolic content of Echinacea purpurea and E. purpurea `Magnus' is influenced by fertilization after flower bud removal and vegetative pruning. The second objective of this study is to form an evaluation of the differences in biomass and phenolic content of five cultivars of E. purpurea and five species of Echinacea. Biomass and phenolic content will be evaluated to determine if exposing these plants to various treatments increases the quality of the plant over 1 and 2 years of growth. Differences in dry weights of Echinacea species and cultivars harvested after the first year of growth was determined. There was a significant difference in total dry weight between E. purpurea cultivars. Echinacea purpurea `Bright Star' and `Clio' significantly produced the most total dry weight compared to all other cultivars. There was no significant difference in root or flower biomass between cultivars. Biomass of Echinacea species was significantly different in root, vegetaive and flower parts. The total biomass of E. purpurea and E. tennesseensis was significantly higher compared to other species. Echinacea pallida and E. paradoxa were not significantly different from E. purpurea in root biomass, even though both species were small in above ground growth. Echinacea tennesseensis significantly produced 45% to 105% more flowers compared to other species. Differences in phenolic content between species and cultivars will also be presented.
Sanliang Gu, Susanne Howard, and Martin K. Walsh
The effects of shoot positioning, leaf removal, cluster shading, and curtain orientation on fruit composition and primary bud cold hardiness were investigated in mature `Norton/Cynthiana' grapevines (Vitis aestivalis) trained to Geneva double curtain (GDC) trellis system. For four years (1995–1998) juice soluble solids content, total titratable acidity, and pH were not affected shoot positioning. Cluster shading, curtain orientation, and leaf removal affected fruit composition at harvest. Fruit from the south-facing curtain of the GDC trellis system had higher juice soluble solid content, pH, and skin pigmentation than fruit from the north-facing curtain. Cluster shading decreased skin pigmentation while cluster shading at the highest level only (95%) increased pH and decreased total titratable acidity. Leaf removal, which increases light exposure of the fruit, increased juice pH in the 1997 experiment only. Juice potassium level was decreased by shoot positioning, but not cluster shading or curtain orientation. Cold hardiness of primary buds was affected by these treatments early in the winter, but the differences in primary bud cold hardiness among the treatments diminished toward the end of the dormant season.
Patrick P. Moore
Allan B. Woolf, John Clemens, and Julie A. Plummer
Six concentrations of ethephon were applied to plants of `Donation' and `Anticipation' Camellia (L.) at two times (late summer and autumn) and three times (late summer, autumn, and midwinter) of the year, respectively. Abscission of leaves and floral and vegetative buds was determined. Sensitivity to ethephon varied markedly among plant organs. Greater sensitivity of floral buds indicated that ethephon could be used to selectively remove these with minimal abscission of other plant organs. Proportion of abscised organs varied with cultivar and time of application. Chemical name used: (2-chloroethyl)phosphonic acid (ethephon).
Allan B. Woolf, John Clemens, and Julie A. Plummer
The influence of temperature and leaf maturity on ethephon-promoted abscission was examined by simultaneously applying either ethylene (10.5 μl·liter-1) or ethephon (0 to 4 ml·liter-1) to potted Camellia plants at four constant temperatures (10 to 30C). The abscission rate (time to 50% abscission) and extent of abscission of leaves, and vegetative and floral buds was measured. Increased temperature promoted the rate and extent of ethephon-promoted abscission and increased ethylene-promoted abscission rate of all organs of Camelliu. Lower temperatures reduced the abscission rate after ethephon application more than that following ethylene application. Sensitivity to ethephon was greater for leaves on newly extending shoots, although once shoot elongation and leaf expansion had ceased, leaves became less sensitive. Ethephon sensitivity increased progressively with maturation over the following 2 years. Optimal thinning of floral buds. at low temperatures required high ethephon concentrations, while at high temperatures, low ethephon concentrations were optimal. The influence on abscission of the time of year when ethephon was applied, is suggested to be due to tissue maturity, which affects tissue ethylene sensitivity, and temperature, which affects ethylene release from ethephon and tissue response to ethylene. Chemical name used: (2-chloroethyl) phosphoric acid (ethephon).