L.) are included in the top 15 flowering and foliar annuals in terms of annual sales ( U.S. Department of Agriculture, 2014 ). Marigolds are one of the premiere garden annuals that perform well in dry, hot conditions and are frequently used as a
Kevin M. Heinz, Polly A. Harding, Maria Julissa Ek-Ramos, Heather Hernandez, Peter C. Krauter and Gregory A. Sword
Christopher S. Cramer, Narinder Singh, Neel Kamal and Hanu R. Pappu
, plants that exhibited fewer IYS foliar symptoms on maturing foliage were selected and kept separate from other bulbs harvested from the plot. Leaves and roots from the harvested bulbs were removed and bulbs were stored. Bulbs, selected for reduced symptom
Graham H. Barry and Smit le Roux
concentration unmasks the presence of carotenoid pigments followed by further synthesis of carotenoids, resulting in the first appearance of the characteristic orange color of mandarins and sweet oranges ( El-Zeftawi, 1978 ; Goldschmidt, 1988 ; Jackson and
P.A. Bowen and W.M. Kliewer
Two-dimensional partitioning of variation was used to determine the sources of relationships between the yield and vegetative characteristics of three `Cabernet Sauvignon' grape (Vitis vinifera L.) clones. Clonal differences were found in shoot growth rate, but not in duration or total growth. A weak positive relationship between total shoot growth and yield resulted from a positive relationship between fruit set and growth duration. Relationships between cluster number and foliar characteristics indicated that light exposure in the previous year may have influenced both vegetative and reproductive development. The mean number of clusters per bud was positively related to the mean area, dry weight, and nitrogen content of leaves.
Mark H. Brand
The effect of shading during nursery production on the growth, foliage color, and foliar chlorophyll content of container-grown Kalmia latifolia cultivars was investigated. Five cultivars were grown under 40% shade, 60% shade, or full sunlight for a 2-year production cycle. During the first year of production, there were no significant differences in measured growth characteristics for most cultivars in response to light treatment. Shade improved foliar color by decreasing lightness (L*), decreasing chroma, and changing hue angle from a yellow-green to a darker green. Foliar chlorophyll concentration increased under shade. In the second year of the production cycle, the response of foliar color and chlorophyll concentration to shade was similar to that observed in year 1. Plant size, number of branches, leaf area, leaf dry mass, and stem dry mass decreased linearly with increasing shade in year 2. Although shading improves foliar color, it probably should not be employed for container production of Kalmia latifolia in cool, northern production areas due to reduced plant growth during year 2. Shade may be useful in the first year of production to enhance foliar color without reducing shoot growth.
J.D. Norton, G.E. Boyhan and J.A. Pitts
The dwarfing characteristics of St. Julien and Pixy rootstocks as measured by shoot growth and trunk cross-sectional area (TCSA) was evident. Tree survival was significantly reduced after 3 years on Nemaguard and Pixy rootstocks. None of the elements measured by foliar nutrient analysis were below the minimum for plums; however, significant multiple regression equations for total shoot growth, TCSA, and survivability were evident with R 2 of ≈0.30 in all three cases.
R. Scott Johnson, Rich Rosecrance, Steve Weinbaum, Harry Andris and Jinzheng Wang
The suspected contributory role of soil fertilization to nitrate pollution of groundwater has encouraged exploration of novel fertilizer management strategies. Foliar-applied urea has long been used to supplement soil N applications, but there have been no apparent attempts to replace soil N applications completely in deciduous orchard culture. Two experiments were conducted to study the effect of foliar-applied low biuret urea on productivity and fruit growth of the early maturing peach [Prunus persica L. Batsch (Peach Group)] cultivar, Early Maycrest. In a 3-year experiment, a total foliar urea regime was compared to an equivalent amount of N applied to the soil. The foliar treatment supplied adequate amounts of N to the various organs of the tree including the roots, shoots, and fruit buds, but mean fruit weights were lower than in the soil-fertilized treatment. In a 2-year experiment, a 50%-50% combination treatment of soil-applied N in late summer with foliar-applied N in October, maintained yields and fruit weight equal to the soil-fertilized control. Some soil-applied N appears necessary for optimum fruit growth. Soil N application may be needed to support root proliferation and associated processes, but we did not determine a threshold amount of soil-applied N needed. The combination treatment also reduced excessive vegetative growth which is characteristic of early maturing peach cultivars. Therefore, this combination treatment offers promise as a viable commercial practice for maintaining tree productivity and controlling excessive vegetative growth in peach trees.
Osman Karaguzel, Ibrahim Baktir, Sadik Cakmakci and Veli Ortacesme
The effects of method of application and dose of paclobutrazol on the growth and flowering characteristics of Lupinus varius L. were studied. On 17 Dec., seeds were sown into 18-cm pots (three seeds per pot) filled with a mixture consisting of 2 peat: 1 river sand (by volume). On 25 Mar., when 5% of the plants had elongated first internodes, doses of paclobutrazol at 0 (control), 0.625, 1.250, and 2.500 mg a.i./plant were applied to plants as a foliar spray or media drench. The application of paclobutrazol led to a slight shortening of the time to flowering, especially when applied as a foliar spray. Plant height and internode length, length, and internode length of the main inflorescence significantly decreased with increased doses of paclobutrazol and this also happened with the number of branches per plant, branch length, and length and internode length of branch inflorescence. On the contrary, stem, main, and branch inflorescence diameters significantly increased with increased doses of paclobutrazol, whether applied as a foliar spray or media drench. However, drench applications of paclobutrazol were consistently more effective than foliar spray treatments on most of the growth characteristics investigated. Paclobutrazol, in particular when applied as a foliar spray, also increased the number of flowers on main and branch inflorescences relative to the control, but media drenched applications of paclobutrazol at doses of 1.250 and 2.500 mg a.i./plant resulted in consistent significant reductions in the number of flowers on branch inflorescences. Chemical name used: (±)-(R*,R*)-β[(4-chlorophenyl)methyl]-α-(1,1-dimethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).
Qinglong Zhang and Patrick H. Brown
The characteristics and mechanisms of foliar Zn uptake and translocation in pistachio (Pistachio vera L.) and walnut (Juglans regia L.) were investigated using 68Zn labelling in both intact and detached leaves. Following washing, mature walnut and pistachio leaves retained 8% and 12% of the total Zn applied, respectively. About half of retained Zn (3.5% and 6.5% of total Zn respectively) was absorbed into the leaf and translocated outside the treated area. Leaf age affected the Zn absorption capacity of pistachio but not walnut. Immature pistachio leaves absorbed more Zn than mature leaves. The absorption of Zn by walnut leaves at high concentrations (7.5 to 15 mm Zn) was not significantly affected by the pH of the solution. In pistachio Zn absorption was greatest at pH 3.5 and declined as pH increased to 8.5. The uptake process was not affected by light or addition of metabolic inhibitors. Foliar leaf absorption was only slightly affected by changes in temperature with an average Q10 of 1.2 to 1.4. This study suggests that foliar Zn uptake is dominated by an ion exchange and/or diffusion process rather than an active one. This study also demonstrates the usefulness of stable isotope labelling in studies of foliar Zn absorption.
G.E. Boyhan, J.D. Norton and J.A. Pitts
The dwarfing characteristics of St. Julien and Pixy rootstocks, measured by shoot growth, were evident with `AU-Amber' and `AU-Producer' plum (Prunus salicina Lindl.) scions. Dwarfing did not occur with `AU-Rubrum'. Trunk cross-sectional area (TCA) was reduced with `AU-Amber', `AU-Producer', and `AU-Rubrum' scions on St. Julien and Pixy rootstocks. After 3 years, tree survival was 94% for Lovell; 89%, Halford; 57%, Nemaguard; 75%, Nemared; 83%, St. Julien; and 47%, Pixy. Tree survivability was significantly lower on Nemaguard and Pixy rootstocks than on Lovell and Halford. Multiple regression of total shoot growth, TCA, and survivability against foliar nutrient content resulted in the following significant equations: 0.460Mg - 0.210Mn, 0.236B - 0.487Mn, and 0.359N + 0.398Ca - 0.267P - 0.360Fe for each, respectively. Growth, survivability, and foliar nutrient content are significantly affected by rootstock in plum production.